Fukushima: day 131 to 145

Dear Colleaues:

145nd-148th day!

I. Update of the highest contamination detected
This survey was motivated from the unexpectedly low dose rate of air
samping taken from the 1F1 Reactor Containment Building as introduced in
Earthquke (139), which showed that it was not much different from what was
monitore in the Reactor Building. Let me recap the relevant radioactive
concentraton information as attached. As to the concentration of
radioactive species iside of the 1F1 Reactor Building, measured on May 5,
the results indicated aproximately 0.08 Bq/cm3 for Cs-134+Cs-137. The
measurement of the air sapling from the Reactor Containment Vessel was
introduced in Earthquake (13) as summarized below.
Species Bq/cm3
Cs-134 17
Cs-137 20
I-131 UD
These values are only 500 times arger than those at the Reactor Building.
It the reactor core has actally molten through, the dose rates should have
been larger by several ordrs of magnitudes.
Since it was identified that the hot spots are relaed with the route of
venting through the Reactor Building Reactor RoomHeating and Ventilation
System, through Emergency Gas Processing System, the urvey appears to be
performed along this route. Although there were heavyly oaded redundant
filtering units, consisting of dehumidifire units, heatin coils,
pre-filters, HEPAs and Charcoal filters, some of them may not ave worked
as intended under the station blackout situation. Nevertheless, these
filtering unis should have removed a significant portion of the released
radioactive spcies resulting in highly radioactive. This unit should have
worked fr mitigation of some portion of the released radioactivity through
ventin. As a matter of fact, the dose rate records of the temporary
monitoring stations indicate that the dose rate due to venting is much
smaller than that following the hydrogen explosion as well as the subsequent
large release due to, potentially, a "spontaneous hydrogen explosion." The
ventingwas not the largest release from 1F1 as shown in the attached graph
shoing a correlation of Monitoring-Events. Thee is also a possibility of
back flow through a ventilation duct to the room discharge ports to the Fuel
Handling Room, resulting in retention of the effluent through venting.
On August 4, TEPCO released a photo of aother 3.6 Sv/h hot spot,
located at the bottom of the Comon Exhaust Stack shared between 1F1 and
1F2. It is from a rain water drain line from the stack as attached
donloaded from:
http://www.tepco.co.jp/nu/fukushima-np/images/handouts_110805_02-j.pdf. It
appeas to indicate that there is a pool of condensed highly contaminated
water released by venting at the bottom.

I. Remote hot spot measurement of entire eastern region of Japan
he Government decided to initiate an Overall Integrated Radiation
Monitoring Project, coveing Tokyo and 21 Prefecturesf eastern Japan.
This project is to respond to the public's anxiety against local hot spots.
The detection will use airplane, whose effectivenesshas been demonstrated
by the US DOE/NNEA dose maps and soil contamination maps.
This project s prudent, I believe, since the highly contaminated sewage
sludge have been reported fromNW areas around Tokyo where no contamination
maps are available.

III. Relaxing the 20-30 km "Emergency Preparedness" Zone
The Government is currently investigating towardly relaxing of
restrictions imposed on the 20-30 km "Emergency Preparedness" Zone, such as
by producing detailed dose maps. On August 4, Nuclear Safety Commission
(NSC) released their view fo this direction. The new guideline will be;
(1) A possibility should be beninly small for future emergency evacuation
from this zone.
NISA/TEPCO asured that the current most critical issue is continued
water injection ino the Reactor Pressure Vessel. Even in severe
malfunctions, they should be ble to recover the current essential safety
functions within three hours, suh as by having fire-engines in standby.
(2) Dose rates from the time of r-habitation to this zone in the coming one
year should be less than 20 mS and will be expected to be reduced below 1
mSv/y in long te, through environmental monitoring and decontamination.
For the requiremnt of the Point (2), the below 20 mSv/y may be easily
achievable, however, te below 1 mSv/y in the long range future is expected
to be extremely difficult. Even if the "Scheduled (and organized)
evacuation" zone is not included, there ae several hot spot areas in
Kuzuo-mura,amura-shi, Kawauchi-mura as well as Iwakishi, due deposition
of Cs-134 (T1/2=2.01a) and Cs-137 (T1/2=30.0a), whic may not decay for a
long time. A very high dose rate corridor is stretchin as far as 60 km
towards t NW direction from the Fukushima Daiichi. The hot spots areas
appear to amount to nearly a half of the residual zone. Thi
characteristics are clearly shown in the US DOE/NNEA dose maps
http://eergy.gov/articles/us-department-energy-releases-radiation-
monitoring-data-fuushima-area

It appears like many scientists are making a mistake since the urrent high
air dose rates are not from effluent released from the dmaged plants rather
it is due to ground shine from the soil contamination.

IV. Update of the water purification system
The unstable and resultant low availability operation continue in the
water purification system. On August 5, a worker found approximately 700
liters of the flushing water leaking from a line used for decontamination of
the sorption tanks. The activtion level is of the same order of magnitude
as the highly contaminatedwater, although there was no external release
from the Centralized Waste Pocessing Building. Earlier to this, the
system stopped for 2 Hours reprtedly due to a freeze of a portable computer
used for process control.
TEPCO is trying to replace two horses, one from the Kurion's process to
the AREVA's c-deposition process and the other from that to the treated
water storage tak (SPT). They appear to believe firmly in that the flow
decrease is due todeposition of sludge, although no chemical sampling data
has been released rom them.
Although it was planned to start the overall commissioning testof the
new zeolite sorption facility, TEPCO decided to process the lmost fully
accumulated highly contaminated water being stored a the basements of
Centralized Waste Processing Facility. The water hasaccumulated as high as
30 centimeters from the storage limit. The new facilty is being
constructed by Toshiba in collaboration with Shaw Group.

V. pdate of internal exposure in live stocks
Since I covered this subjct in July 30 as Earthquake (134), this issue
has been the major topicsin many Japanese media. The Government decided to
dispose a 3500 live stocks which have been traced to be fed with the
contaminated straw feed. They have been thinking of putting them in storage
for veral months waiting for detailed screening by dosimeory, however
they judged that the consumer may refrain from buying the screened beef meat
even after found below 500 Bq/kg of cesium. All of them will be incinerated
for disposal.

Let me stop here tonight!


Genn Saji
_______________________________________________________________________
(Previous e-mail sent at 10:29 P on Aug 2 as Earthquake (139,July 30-Aug
2))
Dear Colleagues:

142nd-145h day!

II. Update of 1F4 SFP (5th floor)
Last time I covered this subect was in Earthquake (111) sent on June
30. After that TEPCO completed repairing the damaged pool load bearng
structural wall by inserting the additional steel columns and filled withement grout. As soon as it was completed, a new air cooler was installed
tothe Spent Fuel Pool to recover the circulation cooling capabilities. On
Jly 31, TEPCO announced that the system started to work. The current pool
water temperature of 85 $B!n (B is expected to drop quickly. At 6:00 AM on August
1, the temperature was 64.2 $B!n (B With this, all of the SFPs of Fukushima
Daiichi have now recovered the crculation water cooling capabilities. This
will enable to unload TEPCO's urden for accident management greatly.

III. Update of the water purificationsystem
The unstable and resultant low availability operation continue in he
water purification system. At around 10:50 AM on July 31, a worker found
leakage from a horse from the Reverse Osmosis Process to the condensed ater
storage tank. After replacing the hose, the system went back to opeation
at around 3:00 PM of the same day. Although the leakage is not lare, being
approximately 50 liters, this leakage is more of the concern than th
leakage of RO treated water, since the leaked water may be condensed with
nn-cesium radioactive impurities, such as strontium.
A potential relief s that a new sorption process, named Sarry, has been
installed and currenty under water flow test. This is to backup or
substitute the US Kurion's rocess. It consists of 14 sorption tanks each
with 1.4 meters in diameer and 3.5 meters tall.
In addition, AREVA's as well as Toshiba's evapoator systems for
processing the condensed sea water discharge from the Revrse Osmosis water
purification ocess is also being installed. The recycled water from this
process will also be used as a part of the circulation cooling water.
Without the evaporation system, only 40% of water can be used from the RO.
A photo is released from TEPCO as attached:
http://www.tepo.co.jp/nu/fukushima-np/images/handouts_110801_04-j.pdf
With these aditional processes, the illustration of the total water
purification syste has also been updated as attached.
http://www.tepco.co.jp/nu/fukushima-np/iges/handouts_110801_05-j.pdf
In the figure, the process, encircled with red broken line on the top,
is a newly added evaporation system. The new esium sorption process is
stacked on top of the Kurion's system atthe middle of extreme right.
Although these new workhorses are certainl welcome, I am not so
optimistic to expect a drastic improvement in the otal availability of the
water purification system, since the most troublesome part of the rocess
seems to be more in the water chemistry management of these conceptn
general, in particular in the corrosion issues after the first stage
soption systems. The water chemistry of the water treatment system is an
unknwn area of science and engineering for the highly contaminated water
whre the high radiation seems to be upsetting the passive characteristics
of meals.

IV. The highest contamination detected
TEPCO announced that he highest level of contamination, with the dose
rate of above 10 Sv/h, beyon the off-scale limit, was detected at the
bottom of the exhaust duct for 1F1/1F2. on August 1. The vnting operation
performed in 1F2sed this route for discharging steam from the containment
vessel on March 12. TEPCO is currently investigatin further details of
this hot spot.
However, the beyond 10 Sv/his not just limited there. TEPCO detected
two additional hot spots oe at the bottom of the exhaust stack and the
other at junction of the Emergency Gas Treatment System on August 2. A
gamma camera photo is release as attached.
http://www.tepco.co.jp/en/news/10311/index-e.html Please download Download
Bottom of Main Exhaust Stuck ofUnit 1/2 Connection of emergency gas
treatment piping arrangement (pictured on August 1,2011) as well as
Main Exhaust Stuck of Unit 1/2 (pictured on July 31,2011)
TEPCO was monitoring these locations after removal of contaminated debris on
the ground.
Inside of the reactor buildings, TEPCO announced that above 5 Sv/h hot
spot was detected inside of 1F1. The human entry to this room was
prohibited.

Well,let me stop here tonight!

Genn Saji

__________________________________________________________________________
(Previous e-mail sent at 9:50 PMon July 30 as Earthquake (138,July 28-30))
Dear Colleagues:

140th-142nd day

I. Sampling of the atmosphre inside of the Reactor Containment Vessel
On July 28, TEPCO announce tat they will perform a sampling of
atmosphere inside of the Reactor vessel, starting with 1F1 on July 29,
followed with 1F2 in erly August. This is to characterize the radioactive
species release into he containment vessel, to facilitate mitigation of
environmental effluent rlease. The data is expected to clarify how much of
corium has been released from the reactor vessel through the TEPCO' early
"mlt-though" scenario. The sampling will be performed by installing a
temporry branching line to the oxygen concentration monitoring line as
shown in theattached illustration (in Japanese).
http://www.tepco.co.jp/nu/fukushimanp/images/handouts_110728_03-j.pdf
On uly 30, the results of sampling were released as attached (in
Japanese): http://www.tepco.co.jp/nu/fukushima-np/images/handouts_110730_01-j.pdf
The cncentrations of cesium are not much dierent as observed in the air
sampling in the Reactor Building;
Species Bq/cm3
Cs-134 17
Cs-137 20
I-131 UD
I believe the TEPCO/NISA's meltdown scenario is provenincreasingly
unlikely.

II. Update of the TEPCO's "melt-through" scenaio for 1F3.
On July 28, TEPCO also release an update of their assessment f the
plant behavior during the most critical 24 hours between noon of Marh 12 to
March 13. This is a 4 page document in Japanese but let me attach it s is,
since it contains some self-explanatory graphs as attached.
The pdate is concerning the assumption of pipe failure of HPCI (High
Pressure Cre Injection) line, which was assumed to start leaking steam.
This assumptio was necessary to reproduce the actual pressure transient
cue, in the report submitted to NISA on May 23.
As shown in an illustrative figure, the HPCI is a part of ECCS, which is
driven by a steam turbine, extracting steam from the Reactor Pressure
Vessel, by taking water source from the suppression pool or from a
condnsate storage tank. There is also a "minimum flow line" injecting the
water back to the suppression pool. Since it is a turbine-driven, it should
continue operation as long as the battery powr is reserved for controlling
this system.
In the previous analysis by TPCO released in May 23, the reactor water
level was predicted to decrease ve rapidly with the termination of HPCI,
perhaps due to the assumed pipe brek, reaching to the BAF (bottom of active
region of the fuel) at 42 hours ater the reactor trip. In the new
analysis, it is 43 hours after the ractor trip as shown in the MAAP
calculation. Although TEPCO explain that the overall conclusion is
unchanged, I doubt it because the freshwater injection was started before
that timing. Also, the new calculatin is showing rapid recovery of water
level by the water injection up to 2 mers from the TAF. In addition, the
actual level gage indication is showingthat the water level has never went
below BAF. If the reactor core is artially submerged under war, up to
the half way, it is difficult to understand the TEPCO' melt-through
scenario. The experimental results have beenshowing that the water droplet
through boiling hit the upper portion o the fuel resulting in no melting.
Of cause there is an uncertainty that the evel gauge may not be predicting
the true value, if the "internal hydroge explosion" has experienced as in
the eight cases of similar accident experenced inside TEPCO.
TEPCO reports that the water source of HPCI opeion was the cold water
from the Condensate Storage Tank and, therefore, he pressure of the Reactor
Vessel can decrease with the operation of theHPCI. It is strange again how
to explain the cyclic pressure fluctuationwhich appears to be induced by
the mechanical action of the Automatic Release and Safety Valves (RSV),
whose safety valve function should have released steam without relying on
battery power. The ressure control does not seem to be established by the
cyclic operation of HPCI but through action of RSV in Figure 1. The
decreased pressure and automatic pressure release though RSV are not
consistent.
TEPCO concludes that the sudden pressure decrease as soon as the Reactor
Isolation Cooling System (RSIC) stopped at around noon of March 12 isdue to
the injection of the cold Condensate Storage Tank water. However, the
timing of the start of the actual pressure decrease and the starting time of
the cold water injetion through HPCI is off by nearly three hours in Figure
2. Although the pressure recovery history seems to agree reasonably well,
however, this time deviation does not eem to support TEPCO's claim.
The gradual pressure increase in the Dry Well pressure in the late
evening of March 11 seems to indicate that there is a leak pass from the
Reactor Pessure Vessel to the Reactor Containment Vessel, which changed
into a decease at around noon of March 12 in the actual pressure
indication. This seems to indicate an existence of another leak route from
the Reactor Containment Vesselto the Reactor Building. This must have
released a significant amount of hydrogen accumulated in the Reactor
Containment Vessel.
TEPCO's revision of the assessment was motivatedby the follow on
investigation of the status of HPCI at that time. They found that a worker
has entered into the room to restart RSIC through the room where HPCI is
installed. If thre is a pipe break in the HPCI, such a human entry should
have been impossible. They report that the HPCI should be operated to keep
the reactor water level between L2 (low level) andL4 (high level), however,
I do not believe such operation was intended to substitute the action of
RSV, although the specification itself is reasonable.
For me, the whole new story s more confusing, induced from TEPCO'
stubborn policy (?) of ignoring the effect of "feed and bleed" operation,
which seems to have successfully prevented the core melting, I believe.

III. Update of 1F3 dose maps and water injection
On July 28, TEPCO released a video of the Quice Robot observation of the
Unit 3 in: http://www.tepco.co.jp/en/news/110311/index-e.html Please
download:
Video by Quince Robot within Fukushima Daiichi Nuclear Power Station Unit 3
reactor building(ZIP 12.6MB) (video on July 26, 2011)
It is impressive to observe that, although the top part of the 1F3
reactor building has been blown off by the hydrogen explosion, the lower
floors look much less damaged although some debris preventing further access
by the robot.
TEPCO also updated the dose map, showing a spot with 280 mSv/h at the
shielding box of a high pressure water injection valve as attached. This
high radiation spot is likely due to a leakage of the primary water into the
box.

IV Update of internal exposure in live stocks
Since I covered this subject in July 22 as Earthquake (132), this issue
has been the major topics in many Japanese media. Through tracing the
distribution route of the contaminated rice straw feed, the following
statistics are shown:
Total number of potentially contaminated beef stocks: 2965
Stocks currently under tracing approx. 2500
The identified contamination of the meat out of 393 stocks: 31
It is reported that the contaminated stocks will be purchased by
agricultural associations, who will delegate to get compensation from TEPCO.
The Government has issued an order for restriction of marketing all meat
cattle from Fukushima and Miyagi under the Law of Nuclear Disaster Law, to
be followed with a few additional prefectures. The restriction will be
released as soon as the local government established screening process of
individual beef stocks for the potentially contaminated stocks identified to
have consumed the contaminated rice straw feed.
For the screening process, the government is considering to allow dose
rate measurement by using survey meters with a temporary acceptance criteria
of 250 Bq/kg in 15 minutes of counting, followed by detailed lead shielded
chamber measurement for samples exceeding this criteria. The equipment for
the detailed measurement is very expensive and limited to only a few units
available for most of the prefectures. I believe this is practical, however
if that can be allowed, the contact radioactivity measurement of the live
beef stocks should also be acceptable, since cesium is known to distribute
almost uniformly in the body.

V. Recapping on accumulation of $B!H (Bradioactive $B!I (B sludge and ashes
I introduced this issue more recently in Earthquake (95), (97) and
(108), the last one in June 27. The most recent statistics collected by the
Yomiuri News paper working with Ministry of Health, Labor and Environment
are:
Drinking water purification facilities: 91,920 tons
Sewage water treatment facilities: 30,450 tons
Although the local governments are asking for disposal by the Government as
radioactive wastes, Fukushima Prefecture is reported to start to sound
acceptability of the wastes in their (ordinary) ultimate waste disposal
facilities for the 'low level contamination' wastes with a level of 8,000 -
100,000 Bq/kg.
In many facilities, the temporary monitored storage is approaching to
their capacities within a few months. The local governments are urging
action to be taken by the national government.

Well, let me stop here tonight!

Genn Saji
____________________________________________________________________________
(Previous e-mail sent at 6:26 AM on July 28 as Earthquake (137,July 27-28))
Dear Colleagues:

I observed that the Fukushima Daiichi situation is still far from being
settked down and there are many important press releases and announcements
made every day from various organizations. Let me send this updates without
waiting two more days until Saturday.

139th-140th day!

I. Update of the "Stress Test" for all NPPs in Japan
I introduced this subject in Earthquake (126) and (132). Mr. Izumida,
Mayor of Niigata Prefecture and is the Chairman of Mayors' Special Committee
on Counter Measures against Disasters, briefed at a press interview that the
stress test is better than nothing but local governors will not accept the
results of the stress tests for re-starting the nuclear plants. It is
because the test is being performed on the bases of pre-disaster knowledge.
He pointed out that the verification of the accident has not been completed
yet. The committee has submitted an "Urgent Proposal for Reorganizing
Nuclear Administration" to the National Government on July 12. They are
proposing the following 6 items:
(1) Early settlement of the Fukushima Nuclear Disasters
$B!& (Bby integrating the available best national and international
expertise
$B!& (Bearly confinement of radioactivity
$B!& (BA new set of safety criteria for protection of welfare of next
generation children
(2) Safety assurance of nuclear power plants as well as Emergency
Preparedness Provisions
$B!& (Brevision of safety criteria as well as safety provisions by going
through through examination and verification of the disaster
$B!& (Brevision of emergency provisions, including EPZ (Emergency
Preparedness Zone) as well as promotion of countermeasures by the
local government
(3) Disclosure of information and adequate explanation
$B!& (BDissemination of information relevant to the disaster as well as
systematic analyses and explain intelligibly to the Japanese people
$B!& (BViews different from the National Government and TEPCO should be
explained clearly
$B!& (BDissemination of information of capability of power supply so that the
local government will be able to discuss with the power companies
(4) Enlargement of different energy options
$B!& (BAccelerate the current administration and development activities
towards different energy options that should enlarge new job
opportunities
$B!& (BEarly establishment of Law of Renewable Energy and initiation of
administrative procedures for fixed price purchase of the energy by
power companies
(5) Presentation of national vision of overall energy policy and nuclear
energy policy
$B!& (BPresentation of available future options as well as supporting bases
$B!& (BPresentation of Government's vision and agreement with public after
going through national discussions

II. Update of the water purification system
Although establishment of closed recycling of the injected water is one
of the most urgent issues, an availability of the water purification system
continues to be much less than the rated capacity. An weekly availability
between July 20-26 was reported to be only 58% and is not much improved from
the previous weekly performance of 53%. This resulted in an further
increase of 3000 tons of the total to 120,650 tons of the highly
contaminated water.
The current issue seems to be in gradual increase in flow resistance in
its 4 km total pipeline due to depositions. The root causes of deposition
are still unknown and the reported in confusion. Some engineers insist this
is due to deposition of sludge. If the sludge means to be from the
accumulated water at the basement of turbine halls, it should be highly
radioactive with mostly "intermediate" and "refractory" species from the
reactor fuel, which should have been removed at least by the RO process.
Other engineers insists that it came from glue used for pluming of plastic
piping. This is also unlikely, since in these days, the plastic piping has
been widely used in Japan for tap water piping, replacing from the old lead
piping. Therefore I have been insisting that it should be due to deposition
of corrosion products, hydrated state of iron oxide induced from
de-passivation at the inner surface of piping and tanks. It is very strange
why TEPCO people do not try to ask for a chemical analysis of the deposits,
since they should have in-house capability to perform such an analysis for
water chemistry control during normal operation. They should have a
capability to perform chemical analyses of the water up to a ppb level.

III. Update of 1F3 dose maps and water injection
The recent most relevant explanation of the 1F3 situation was covered in
Earthquake (120) on July 9 and (123)-attachment on July 12. The 1F3 is
generating twice as large amount of highly contaminated water as compared
with 1F1 and 1F2, due to a potential leakage of the injected water.
The current water injection rates are:
Unit Injection rates T at feed water nozzle T at lower RPV
1F1 3.8 m3/h 108.3 $B!n (B 96.3
1F2 3.5 m3/h 112.3 123.7
1F3 8 m3/h 123.7 108.1

Since the water purification system is not working with a high reliability,
TEPCO decided to switch the water injection line to the ECCS piping. For
that operation, TEPCO made an inspection by Quicy on July 24 (as shown in
the attached illustration
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110727_01-e.pdf,
followed with an entry of 11 TEPCO staffs into the Reactor Building on July
26. They observed that the piping and valves are undamaged, but the dose
rate was as high as 75 mSv/h.

IV. Statistics of high radiation workers
NISA and TEOPCO disclosed a statistics of emergency workers who received
high accumulated doses in March is as follows:
> 100 mSv 480
100 - 50 mSv 1680
As of July 13, the total number of workers currently being monitored with
more than 50 mSv exposure was 111.

Well let me stop here tonight!

Genn Saji
____________________________________________________________________________
(Previous e-mail sent at 10:19 PM on July 26 as Earthquake (136,July 25-27))
Dear Colleagues:

136th-138th day!

I. "Action Plan" for detailed radiation monitoring map
MEXT (Ministry of Education, Culture, Sports, Science and Technology),
together with the Life support Team for Affected Residents of the Nuclear
Emergency Response Headquarters, release an action plan for constructing a
detailed radiation monitoring map for rehabilitation to the "Emergency
Preparedness" (20-30 km) Zone.
It consists of the following three objectives.
(1) Radiation monitoring at the sites of education facilities, including
grade schools, high schools, kinder gartens and day nurseries for pre-school
children, as well as hospitals, libraries, children' centers, welfare
facilities for handicapped children and after-school child care centers. An
air dose monitoring by NaI scintillation counters at 50 and 100 cm above
ground will be performed.
(2) Detailed monitoring of living spheres around the schools and care
centers for young children, with mobile survey equipment as well as remote
operation helicopters, covering school-commuting roads and parks. Dose maps
measurements by employing cars, motorcycles and on foot. For "satoyama" (a
semi-natural area that coexists with a nearby populated areas, it used to be
an important source of bio fuel, food, compost, etc.), through remote
operation helicopters widely used for agriculture, such as for splaying
agricultural chemicals and surveying. It's size is approximately 3.6 meters
long and 3.1 metes wide. This operation is for initial trials.
(3) Other locations upon requests from the local governments. An appropriate
monitoring methods will be selected.
The resultant dose maps will be released as early as in mid August.

II. Update of the water purification system
An low flow alarm was generated from the desalination process of the
Water Treatment Facility, issued around noon and suspended its operation for
7.5 hours on July 24. According to the TEPCO's explanation, the RO (reverse
osmosis) stage of the process seems to be clogged and switched to an backup
unit as indicated in red in the attached illustration. Although it appears
to indicates a time for replacement of the RO cartridge, TEPCO concluded
that the root cause of the problem was through sucking of air bubbles into a
feed water pump, due to an inadequate control level setting in the feed
water tank, perhaps meaning insufficient NPSH (net positive suction head).
The RO process essentially filters out the salt contents from the water and
it is not surprising that the cartridges clogged after a prolonged
operation. The system went back with a half capacity by using a backup
cartridge at around 7:30 PM of July 24 and then went back to full capacity
at 1:00 PM PM July 25 by re-adjusting the level setting. However, in order
to replenish the water necessary for injection, the filtered natural water
was supplied to the feed water tank for the water injection system.
The insufficient NPSH seems to indicate that the flow rate from the
AREVA' co-deposition process has decreased, indicating a possibility of
gradual clogging due to sedimentation of corrosion products (hydrated
oxides) somewhere inside of the process.
Since the clogging problems began to occur almost all processes involved
in the water treatment of highly contaminated water, obviously in-depth
studies are needed to bring the damaged reactors into the "cold shutdown"
state, without resulting in a significant increase in the total volume of
the highly contaminated water. For that, prevention of corrosion-induced
material transport and deposion is one of the most difficult issues at this
moment. For prevention of corrosion, often hydrazine is added as a corrosion
inhibiter. However, it will reduce the redox potential, which should
accelerate de-passivation and deposition process in this case. It is
because the redox potential of the treated water should be very low due to
radiation, which reduce the dissolved hydrogen and further increase the
concentration of dissolved hydrogen. Therefore, I am proposing to raise the
redox potential by increasing the concentration of dissolved oxygen to
prevent de-passivation.
Although the de-passivation should be occurring everywhere including and
after the Kurion's sorption process, the resultant hydrated corrosion
products products should be removed by the RO desalination stage considering
the MWCO (molecular weight cut-of) of the RO membrane. However, the
corrosion products generated after the RO process should not be carried over
to the reactor core. In consideration of this, what is missing in the total
water treatment system should be a stage of ion exchange resin filters
(demineralizer) for removal of cation (positive ion) impurities from the
water as done in the primary water systems. employed during the normal
operation.

III. Restriction of usage of leaf mold, compost and cow monure
With wide spread radioactive cesium contamination among cattle,the MAFF
(Ministry of Agriculture, Forestry and Fishery) called for refraining from
using fertilizers made from leaf mold, compost and cow monure made in Tohoku
and Kanto Districts until when a new guideline should be developed. Such a
wide spread contamination, although the levels are very small, being
condensed in the natural environment.

Well, let me stop here tonight!


Genn Saji
_____________________________________________________________________
(Previous e-mail sent at $B!! (B0:00 AM on July 25 as Earthquake (135))
Dear Colleagues:

135th day!

I am planning to reduce a frequency of this updates to twice a week starting
tomorrow. I intend to send on Tuesday and Saturday, since TEPCO's press
release document have often posted late in the evening.

I. Update of the water purification system
For last 6 days, the 1F1 temperature at the lower portion of the Reactor
Pressure Vessel was kept below 100 $B!n (B, by increasing the re-cycled water
injection rate a little bit. Currently it is between 96 to 97 $B!n (B. However
the flow rate tends to decrease gradually and so TEPCO is investigating how
to stabilize the feed water line using the re-cycled water.
Again I suspect that the hydrated state of the corrosion products of
iron is brought over from the water purification line and depositing at the
reactor core as well as piping of 1F1. What is urgently needed is an
in-depth radiation- and electrochemical studies (water chemistry study) of
the overall water purification and water injection system.

II. Update on the city-wide radiation health assessment in Fukushima
I started to monitor this issue in my Earhquke (77), (99) and (105).
The Fukushima Prefecture Government has started radiation health assessment
for their entire population of 2.02 million people, for monitoring their
radiation health as long as for coming 30 years. On June 27 their
$B!H (Bpreceding survey $B!I (B has been started to measure internal exposure, mainly
thyroid doses, by selecting 120 residents out of 28,000 villagers living in
the highly contaminated region (within $B!H (Bscheduled (and organized)
evacuation $B!I (B zone) from Iidate-mura, Namie-machi and a part of Kawamata-cho.
On July 23, the National Institute of Radialogical Science (NIRS,
http://www.nirs.go.jp/ENG/index.html ) reported the results of their
dosimetry of those people who received the whole body dose monitoring, as
well as urine analysis. The results indicated that none of them received
the internal exposure higher than 1 mSv during the course of the accident.
Assuming that they are using a tissue weighing factor of 0.05, it means that
the thyroid doses were less than 20 mGy and certainly there is no thyroid
cancer concern even among the children.
In spite of this, Fukushima Prefecture decided to monitor thyroid by
ultrasonic technology to their entire 360,000 children of under 18 years
old, for every two years for those in ages below 18 years old, and every 5
years for those over 18 years old for their entire life span. It is
motivated from the lessons learned from the Chernobyl accident, where the
thyroid cancer began to appear after 4-5 years. I think the dose rates of
the Chernobyl children are higher by a few orders of magnitude than
Fukushima children according to UNSCEAR 2000 Annex J, and looks more for
assuring a sense of security in stead of a scientific purpose. The major
pathway was through an ingestion; pasture -> cow -> cow milk -> human;
induced because a timely restriction of ingestion of milk was performed too
late in Russia at that time.
I have once looked into the radiological consequence issues of the
Chernobyl accident as reported in PSA05 (2005, San Francisco) on theoretical
reconstruction of the radiological consequences and lessons learned from the
Chernobyl accident (3 papers).

Well, let me stop her tonight!

Genn Saji
__________________________________________________________________________
(Previous e-mail sent at $B!! (B10:46 PM on July 23 as Earthquake (134))
Dear Colleagues:

134th day!

Typo in earthquake (130)
The dose rate value of 1mSv/h should have been 1mSv/y, in the following
description.
(2) The interpretation of "cold shutdown" is (i) the temperature at the
lower portion of reactor vessel should be below 100 $B!n (B, and (ii) the
additional release of radioactivity is reduced substantially, less than 1
mSv/y (not 1 mSv/h). This will be achieved by improving the cooling
capability of the reactors through the re-cycled water injection and air
cooling system.

I. Update of the large scale station blackout of the external power supply
It was reported that the cause of the blackout occurred on July 22 was
due to an error in a setting of an over-current protection sensor (appears
to mean "thermal") of the 6.6 kV circuit breaker. The setting was
inadvertently made 1/3 of the rated capacity of the Standby transformer,
setting at 210 ampere, instead of 672 A. The line was feeding electric
power to 1F3 and 4, as well as the common waste processing building, in
which the water purification system was installed. The power to 1F1 and 1F2
is being supplied from another transmission line from the Tohoku Electric,
and thus the water injection operation in these units were not affected.

II. Update of the water purification system
I covered this subject in Earthquake (129) on July 19. TEPCO decided to
replace approximately 100 meters of steel pipe with an backup vinyl hose to
coupe with the gradual flow decrease to 37 tons per hour, from the rated
flow rate of 50 tons per hour. In the TEPCO's explanation, the decrease in
the flow rate is due to a heavy deposit of "pasty" substance inside of the
steel pipe. This is an interesting observation, since it seems to indicate
that the "pasty" substance is a form of hydrated state of ion oxide,
Fe(OH)2. Although the color of this substance was not reported, it should
look light green. If it is red-brown, it should be FeO(OH). A recent
detailed textbook is

G. K. Schwitzer and L.L. Pesterfield, 2010. The Chemistry of the Elements.
Oxford University Press.

If the "pasty" substance is a form of hydrated state of iron oxides, it
supports my notion that it is essential to ameliorate the water chemistry of
the purified water. By replacing the steel pipe into vinyl horse, it simply
put the corrosion deposition problem to the damaged reactors, which will be
much more troublesome. As a matter of fact, such a gradual decrease in the
water injection line was observed in 1F2, if I remember correctly. I am
increasingly confident that it is essential to raise the redox potential of
the purified water by recovering the concentration of dissolved oxygen.

Well, let me stop here tonight!

Genn Saji
_________________________________________________________________________
(Previous e-mail sent at 7:12 AM on July 23 as Earthquake (133))
Dear Colleagues:

133rd day!

I had to send this Daily Updates this morning, waiting for some of the
essential information released from TEPCO.

I. A large scale station blackout of the external power supply.
TEPCO announced yesterday that a blackout was triggered from a circuit
breaker from the "Backup Transformer" due to overloading at 7:10 AM of July
22. It took nearly five hours to recover at 11:50 AM. During this time some
of the essential accident management facilities, including the water
treatment facility went out of power. It has not been explained to what
extent the blackout affected the accident management. Although it is
reported that some of the essential accident management systems, such as
nitrogen gas pouring and water injection have been continued by receiving
another power source from other transmission line. If so, it should have
been through the temporary cabling from the Tohoku Electric Power Company,
although it has not been mention.
This blackout sequence is hard to understand just from the TEPCO'
sketchy and incomplete explanation, however, it seems to have occurred as
follows. Please refer to an illustrative one line wiring diagram as
attached.

(1) At the time of the event, TEPCO has been trying to recover "Morinomiya
1L Transmission Line" (left on the top) since July 17. During this repair
work of the earthquake stricken transmission route, all of the in house
power supply was switch to other transmission lines, probably to the "TEPCO
Nuclear Line (middle on top) through the "Backup Transformer", which seems
to be not prepared to supply the current the site power demands.

(2) This "Backup Transformer" was overloaded and tripped. It should have
affected practically all the essential power supplies currently relying on
the TEPCO's external power supply.

(3) It appears that TEPCO isolated the transformer and switched to the
"Ookuma 2L Transmission Line" (right on the top), through the 6.6 kV bus
line from the "Backup Transformer."

I noticed that other metal-clad switchgears are "mobile" temporary ones and
have to be replaced into more robust stationary units, therefore, the
recovery work of the "Morinomiya 1L Transmission Line" was being performed.

I felt that there is not sufficient communication among the current
operational procedures of the electrical recovery work among staffs of other
expertise, not with sufficient knowledge of the current electrical power
management, since announcements from TEPCO was confusing. Which system is
receiving from which temporary power sources are not well understood.

II. Relatively low level of contamination in debris at the "Emergency
Preparedness" Zone.
A scoping study made by the Ministry of Environment release that the
sampling data taken from the 20-30 km "Emergency Preparedness" Zone, by
indicating the dose rates of at most 0.79 microSv/h even at 7 km Naraha-cho.
It has also been observed at the time of the Chernobyl accident, that
the near field radiation, such as at Prypyat was not so high as predicted by
the ground level revel release by a few orders of magnitudes. It was
because of blasting of the initial plume high up into the sky. Similarly at
Fukushima, the most severe release occurred by a series of explosions,
blasting the contaminated effluents high up into the sky. The ratianale of
"evacuation" should be re-visited, whether the uniform near field evacuation
up to 20-30 is really warranted for actual reduction of radiation risks.

Well, let me stop here today, for this belated daily update.

Genn Saji
__________________________________________________________________________
(Previous e-mail sent at 0:40 AM on July 22 as Earthquake (132))
Dear Colleagues:

132nd day!

Yesterday, the Nuclear Emergency Response Headquarters and TEPCO
announced that their joint press briefings will be held on every Monday and
Thursday from next week, in view of gradual stabilization of the reactors.
On other days, NISA and TEPCO will have individual press interviews.
I also began to notice that they are having difficulties in finding
reportable topics especially over the weekends. Because of this situation,
I also intend to reduce the frequency of this series of daily updates, in
tune of their schedule. However, let me see how their new schedule will
work for a while, and I may send the daily update more than twice next week.

I. Update of the "Stress Test" for all NPPs in Japan
I introduced this subject in Earthquake (126) on July 15. By going
through a week long discussion, NISA and NSC reached in an agreement and the
final guideline will be released in a few days. A set of distributions are
posted in the NSC website (in Japanese):
http://www.nsc.go.jp/anzen/shidai/genan2011/genan055/index.html

I got an impression that there are not much change in the guideline, except:
(1) The superposition of earthquake and tsunami will be studied also in Step
1, not just limited to Step 2.
(2) Although it is still not clear the difference between Step 1 and 2, the
differences can be summarized as below:
Step 1: clarification of safety margins with respect to the design basis
strengths
Step 2: clarification of safety margin with respect to the actual strengths
demonstrated by experiments

II. Establishing the Task Group of Specialists for Investigation of Mid- and
Long Term Measures
Nuclear Energy Commission, an advisory Government organization to the
Prime Minister, decided to establish the Task Group of Specialists for
Investigation of Mid- and Long Term Measures to develop a new road map for
decommissioning. The announcement (in Japanese) is posted in the NEC
website http://www.aec.go.jp/jicst/NC/about/kettei/kettei110721.pdf
In view of the decommissioning experience of TMI, it is anticipate to
take many years. The missions of the new group of 21 specialists are to
propose:
(1) Approaches for Mid- and Long Term Measures necessary for Fukushima
Daiichi
(2) Agenda for technical development
(3) Approaches for international collaboration

III. Update on preparing for a potential approach of Typhoon #6.
The typhoon, although deviated towards the East, induced a very heavy
rain at Fukushima. At the nearby Namie-machi, the total rain fall was 115
mm. This resulted in an increase of 44cm in the water level at the basement
of 1F1 reactor Building, including the volume of water injection during the
passage of typhoon.

IV. Update of internal exposure in live stocks
This issue was updated on July 19 in Earthqua (130). The most recent
statistics of the beef cattle reached nearly 1500, which were traced down
with a possibility of being fed with the rice straw feed contaminated with
radioactive cesium. Most of them have been already consumed, in almost
entire Japan. The Government is going to incinerate the meat recovered.
By following news reports, I got an impression that the straw left on
the paddy field since last fall worked as sand in the salt farm. The cesium
is concentrated in the straw through sunshine just as the surface sand
concentrate salt. Further quantitative study is needed by measuring
"transfer factor".

Well, let me stop here tonight!

Genn Saji
___________________________________________________________________________
(Previous e-mail sent at 0:18 AM on July 21 as Earthquake (131))
Dear Colleagues:

131st day!

Preamble
One of my colleagues ask me to send the Japanese Government's report to
the IAEA Ministerial Level meeting held during June 20-24. I thought the
report should have been easily available, since many international media
have introduced it. Anyway, let me attached the address of the web archive.
The reference citation is as follows.
Nuclear Emergency Response Headquarters, Government of Japan, Report of
Japanese Government to the IAEA Ministerial Conference on Nuclear Safety -
The Accident at TEPCO $B!G (Bs Fukushima Nuclear Power Stations -. Preprint at
http://www.kantei.go.jp/foreign/kan/topics/201106/iaea_houkokusho_e.html

I. Update on ending the Step 1 and started Step 2 of Roadmap
As anticipated, the overall style of description of the current status
and update of the Road map was received with dubious views by most media as
well as local governments, although they appreciated successful
commissioning of the water purification and injection system.

(1) decontamination, remediation and rehabilitation
I also got an impression that TEPCO's interest is limited to accident
management of their properties, damaged plants, and is not working for
restoration and rehabilitation of the affected areas. Perhaps they are at
lost what to do or politically waiting for the Government to spearhead these
issues. On the other hands, the Government seems to be waiting for TEPCO to
lead issues like decontamination, remediation and rehabilitation. Even
after nearly four months since the accident, everything necessary outside of
the site boundary appears to be left untouched. In particular what to do
with the ultimate disposal of the radioactive wastes generated through the
accident. I am waiting for a strong leadership in these areas.

(2) Reliable water purification system
The success of the roadmap depends much on the commissioning water
purification and injection system, for immediate future. Unfortunately its
availability last week was only 53%, much lower than the projected
availability of 90%, which was reduced to 70% recently. Although the
initial break-in time is over by two months of operation, the root causes of
the low availability, as well as causes of mysterious flow drops, is not
known. I believe it cannot be improved, without recovering "passive state"
by stopping the de-passivated state of the components of the treated water
storage and pumping stage, as well as for those in the AREVA's
co-precipitation process. Unfortunately, there is no water chemistry
specialist with experience of re-cycled water processing facility. TEPCO
should improve this situation as soon as possible.
TEPCO is constructing another system, this time by working with the US
Engineering company SHAW group, as a backup to the existing system. The
system is expected to work as early as August.

(3) "Cold shutdown" state, definition
I am also critical in TEPCO' definition of "cold shutdown state". For
me, an upper portion of the reactor pressure vessel temperature, typically
near the feed water nozzle, should be kept below, say 60 $B!n (B. Instead, TEPCO
is saying that the lower reactor vessel temperature is below the boiling
point. This has already been achieved in 1F1 (currently 98.6 $B!n (B, although
upper portion is 110.2 $B!n (B). It is because of the observation in 1F4 spent
fuel pool, where steam bubbles starts to be released from the pool water
surface even when the bulk pool temperature is below the boiling point,
typically 75 to 90 $B!n (B. The local boiling and resultant release of steam
bubbles accompany radioactive species retained in the bulk water. In order
to substantially reduce the release of radioactive effluent, without the
secondary confinement ("cover"), it is essential to prevent boiling release
of radioactivity, I believe.

(4) Repair of Reactor Containment Vessel
The task of identifying the leak location and repairing the damages of
containment vessel in 1F2 was originally included in the Roadmap as Task 16.
However, this task was deleted, since the focus should be on implementation
of the water purification system.
It is very likely that there exists a whole in each of 1F1-3, since the
nitrogen gas charging to all of them could not recover the normal pressure
of the Reactor Containment Vessel. Currently the pressure is
Unit 1 2 3
N2 gas pressure (kPaabs) 137.3 131 101.6

The damage of the RCV is a very important issue, since around 70-80% of the
injected water is leaking, before finding its way to the reactor vessel.
Without this leakage, most of the injected water can be used to cool down
the damaged core, resulting in early "cold shutdown" state. I have been
saying that the most likely root cause of the containment failure is through
"internal hydrogen explosion" as occurred at Hamaoka Unit 1 in 2002 as well
as 8 cases occurred inside TEPCO.

(5) Installation of air cooler to Reactor Pressure Vessel of 1F1 to 1F3
Although effectiveness of the air cooler has been demonstrated by
successfully installing at spent fuel pools of 1F1 - 1F3, it has not been
installed yet to the reactor Pressure Vessels. TEPCO has not explained in
which pipe this system is going to be connected, whether such a work is
feasible in consideration of worker doses. If such a planning is already
been developed, TEPCO should release it as soon as possible. If there are
some difficulties, further explanation is waited for.

Well, let me stop here tonight!


Genn Saji