Fukushima: day 113 to 119

Dear Colleagues:

119t day!

I. Recapping on the "Stress Test" for all NPPs in Japan
Althogh the word "Stress Test" seems to be well accepted among
politicians, theyall criticized the bad taming and complained that no
details have been reeased from the government. In view of these reactions,
Prime Minister Kan alogized for bringing up this highly technical issue
all in a sudden, acknowldging his delay in ordering to look into this issue
and insficiency in the explanation. One of the focal points of the
current rgument is whether this test is going to become a prerequisite for
re-staring the current fleet of nuclear power plants, 35 of them are in
maintenace shutdown and some of them are waiting for re-starting for the
peak summe load. Mr. Edano, the Chief Secretary of State, was reported to
isue an unified Government view on this issue this afternoon. Inside th
Cabinet, he, Mr. Kaieda, METI Minister, Mr. Hosono, the newly assignd
Minister in Charge of Nuclear Reactor Accident, and Mr. Edan, the Chief
Secretary of State, coordinated their opinions and said to be inagreement.
However, they are investigating how best to disseminate the Gornment
conclusion. Mr. Kaieda is adjusting a schedule to talk about it to
muicipal governments.

II. Recapping on installing nitrogen gas charging into te 1F3 containment
vessel.
In view of unsuccessful attempt to take agamma camera view on the dose
rates and status of the working location to confirm a feasibility of
installing a nitrogen gas charge line to the 1F3 contanment vessel, TEPCO
looked for an alternative route for connection of the nitrogen charge line,
only to find that th dose rate is much higher, being 160-170 mSv/h.
As an alternative, TEPCO announced that their crews is es to confirm the dose rates
near the personnel hatch. Today, from 13:3anned location, located 5 meters above the floor
level, and confirmedntends to start the work as early as on July 9. Although details of
the dose ratesare not released yet, it is likely some temporally shielding
will be applied to reduce the dose rates as low as practical starting
tomorrow.

III. Detailed Fukushima Daiichi tsunami map
TEPCO released today a detailed map that hit the Fukushima Daiichi with
the maximum height of 13.1 meters high. The tsunami resulted from a
consecutivedestruction of five faults, super-imposing 5 waves to became
that height. Oncontrast to this, at Fukushima Daini, these 5 waves were
slightly out of tun, resulting in 9.1 meter high. Let me attach the map,
although in Japanes, the graphs and maps should be self-explanatory, I
hope. In this kind ofmechanism, it is very difficult to predict the
ximum height of tsunami before hand.

IV. Results of the 2nd Airborne Monitoing by the MEXT and DOE
A set on new results are released from MEXT as attached. I am attaching
this, since this has not been posted in the DOE/NNEA web site
http://energy.gov/news/1194.htm

Well, let me stop here tonight,

Genn Saji
________________________________________________________________________
(Previous e-mail ent at 10:21 PM on July 7 as Earthquake (118))
Dear Colleagues:

118th da!

I. Recapping on the "Stress Test" for all NPPs in Japan
Mr. Kaiea, Minister of METI (Ministry of Economy, Trade and Industry)
explainedyesterday his intension to perform "Stress Test" for all 54 NPPs
in Japa. However, the Mayors of local towns and prefectures were all
surprised, b saying that why at this timing, after Mr Kaia visited the
Genkai site and assured that safety improvements were sufficienly
incorporated after the tsunami. Why such a test has not been initiated much
earlier? What is the rationale of doing such a test? They all intensified
dubious view against the Government. As a matter of fact, the municipal
chief of Genkai has called back his earlier decision of accepting the
re-start of the Genkai NPPs.
However, this confusion ems to be induced by the Prime Minister Kan,
who explained that previous aministrative procedure may not be acceptable
for citizens after the Fukushia Daiichi accident. He said he has ordered
to develop a new safety critera, incorporating the "stress tests," even
amendments of relevant laws becam necessary. He has been under a strong
political pressure asking his resigntion. Mr. Kaieda also mentioned that
he will take his responsibility for iducing this confusion in due time,
implying that he may also resign.

II. Recaping on cleaning of debris from the 1F3 reactor building
Yesterday, TEPCO arted to investigate dose distribution inside of the
1F3 Reactor Building, b employing "Worrier" of iRobot Co., putting on top
of a remote working platorm with a gamma camera to investigate the status
near the ceiling level o the first floor.
However, this attempt was not successful, since te remote working
platform interfered with a safety net placed in the reator building. As
high as 38 mSv/h of dose rate was reported at the lcation near the working
place for installation of the nitrogen gas purge injection line. A new dose
map is available as attached:
http:/www.tepco.co.jp/nu/fukushima-np/images/handouts_110707_02-j.pdf
These measureents were made by 9 TEPCO crews, who received the accumulated
dose rates as uch as 2.41 to 6.91 mSv in less than 2 hours of preparatory
work and entry ino the Reactor Building.
TEPCO is investigating how to cope with thiifficulty. It is more
likely that TEPCO may have to find another route for he nitrogen gas
purging.

IV. Recapping on photos and a dose map of 1F4 SFP(5th floor)
After successfully entering to the 5th floor of 1F4 SFP (5t floor),
TEPCO's crew were cleaning he debris. They were successfully reache to two
stop valves of Spent Fuel Pool Cleaning and Cooling Sytem. This will
enable them to leak test of piping before installing an aircooking system.
The operation is projected to be completed by the end of thi month.

Well, let me stop here tonight!

Genn Saji
_____________________________________________________________________
(Previous e-mail sent at 0929 PM on July 6 as Earthquake (117))
Dear Colleagues:

117th day!

I. "Stres Test" for all NPPs in Japan
Mr. Kaieda, Minister of METI (Ministry f Economy, Trade and Industry)
explained today his intension to perform "Stres Test" for all 54 NPPs in
Japan. According to the news interview, he beleves that necessary fety
provisions have been incorporated as requested from METI, however, hehas to
judge necessary to provide peace of mind to citizens living near the Ps,
especially for citizens living near Genkai Plant. The municipal chiefof
Genkai informed the Kyushu Electric Power Company that he can accept therequest for re-starting from the maintenance outage, which went off the gri
since January 29 for Genkai Unit 2 (559 MWe) and December 12 for Genkai it
3 (1180 MWe). Governor of Kyusyu has been requesting Prime Minister to
xplain his rationale for requesting not to start Hmaoka Unit 3 and 4,
locted in the high seismic risk zone. The Government is looking into how
bestto assure a sense of safety among the local people.
METI explained tha the "stress test" is to identify effect of larger
magnitudes of the earthquake and tsunami, simulated by graduall increasing
the magnitudes. They were saying that they will develop a ethodology in
consultation with the Nuclear Safety Commission.
There is aconcern whether this test may affect the operational plants
under maintenane outage. Mr. Kaieda assured that there will be no impacts
in providing effcient electric power.

II. Recapping on the water purification syem
In view of recent relatively stable operation, TEPCO is reported
planing to re-schedule a periodic maintenance operation for replacing four
ceum sober tanks every two days, instead of the projected replacement of
2-4 anks every day. For the maintenance operation, it is necessary to
flush th system for several hours with a low level contaminated water to
reduce the worker doses. This has been inducing a not so high availability
of the system, currently reovered to close to 76% during the last one week
operation. For each maintnance operation, the accumulated doses were as
high as 1.13 mSv. The maxmum surface dose rates of the sober tanks were 6
mSv/h. The replacement is ing performed by a crane with worker
assistance.
In my "back of an envelope" calculation, the contact dose rates can be
as high as 22 mSv/h, although it should be down to approximately 15 mSv/h
due to the furter decay of I-131, when the activity concentration of the
highly contaminted water of the most critical 1F2 values are used.
http://www.tepco.co.jp/n/fukushima-np/images/handouts_110522_04-j.pdf
Concentrations of major radionuclide are;
Species Bq?ml
I-131 2000000
Cs-134 2600000
s-137 2800000
Since the activity concentration of other units are more than one order
of magnitude lower, the current dose rates can be close to the maximum. It
is important to dilute this stream of waste with other streams in the waste
management strategies. Even if such can be done, the current doe rates
seem to be still too high to be able to continue operation. TEPCO should
consider experimenting to swap or bypass the Kurion's system, ad use
AREVA's system for the second stage. The AREVA's system appears to be able
to remotely operate with a minimum worker maintenance design consideraton.
In order to improve the availability, TEPCO plans to have more compact
water treatment facility for each of 1F1-3 by the spring to summer of 2012.
Currently one centralized water treatment facility provides all of these
units through a pipe work of 4 km in total. However, each facility needs to
be installed by constructing new waste tratment buildings, which may take
much longer time. I took this as a part of TEPCO's overall decommissioning
planning as indicated in the roadmap.

III. Recapping on cleaning of debris from the 1F3 reactor building
Today, TEPCO started to investigate dose distribution inside of the 1F3
Reactor Building, by employing "Worrier" of iRobot Co., putting on top of a
remote working platform with a gamma camera to investigate the status near
the ceiling level of the first floor. This operation will be supervised by
PackBot.

Well, let me stop hee!

Genn Saji
______________________________________________________________________
(Previous e-mail sent at 08:43 PM on July 5 as Earthquake(116))
Dear Colleagues:

116th day!

I. Temporary compensation payments fordamages induced by the evacuation
TEPCO has paid 1,000,000/750,000 yen per family/single-family who were
forced to evacuate. However, those pople with big family members
complained uneven, kinder to the single famly. Because of this, TEPCO
decided to pay additional temporary compensatin to evacuees per capita
basis, 0,000 - 100,000 yen, depending on how long they ware forced to
leave home. Details can be found in
http://www.tepco.co.jp/en/press/corp-com/release/1107502-e.html

II. Recapping on "hot spot issues"
I have covered this sbject in Earthqak2 (97) as 'Designated evacuation
promoting' spots. Due to a growing concern towards the "hot spots" detected
outside of the "scheduled (and "organized") evacuation zone, several
municipal governments have initiated their own radiation monitoring
operation.
In view of this stuation, the national government decided to intensify
radiation moitoring operation in wider areas, not only limiting to
Fukushima Prefure, but also including Tokyo Metropolitan Districts, and
Miyagirefecture. So far the Government's concern was limited to 100 km
zonearound the Fukushima Daiichi. To accomplish this, the Government is
gong to resume their helicopter-borne remote radiation monitoring, perhaps
incollaboration with the US DOE/NNEA, although no such statement is givenin the announcement. In addition to this, the Government plans to use
motorycle loaded dosimeters in Fukushima to obtain more detailed dose
information
Although this news is welcome, I am still concerned a bit, why they do
not @refer the direct dose rate monitoring on top of the soil. At this
moment, the largest contribution should come from gamma-ray from the
deposited species on soil surface. This method was widely used at the time
of the Chernobyl accident, but in Japan the soil contamination measurement
is performed by collecting soil samples. By knowing the surface
contamination densities, it is easy to convert it to the dose rates by
assuming an infinite plan source, for example.
In parallel with this, Date-shi, located approximaely 60 km NW of
Fukushima Daiichi, decided to decontaminate the entire city strict by
removing fallen leaves, by washing housings by using high presure water
nozzles, removing surface soils and pavements. The details will be
determined later, bt the city will start with 116 houses and public
facilities located withinthe "Designated evacuation promoting" spots.

IV. Recapping on cleaning of debris from the 1F3 reactor building
I made some misunderstanding as to dose rates. The worker in the
shielded cabin received 0.2 mSv by 2.5 hours of activity, The origin of the
high dose rate is still uncertain. TEPCO is currently preparing to measure
dose rates by employing a gamma camera as yearly as tomorrow. Currently, no
new dose rates asured after placing the steel panels.

V. Isolation of Fukushima Daiichi fro the sea water
TEPCO is constructing concrete barriers in front of the sea water intake
screens of 1F1-4 as posted in
http://www.tepco.co.jp/en/news110311/index-e.html
Download
Construction Status of Mitigation of Contaminaion in the Ocean from Unit 1
to 4(Water intake sliding concrete plate in thescreen)

From the sea water intake pit of 1F2, the highly contaminated watr leaked
out to the sea in June.

Well, let me stop here tonight,


Genn Saji
___________________________________________________________________________
(Previous e-mail sent at 09:17 PM on July 4 as Earthquake (115))
Dear Colleagues:

115th day!

I. Recapping on cleaning of debris from the 1F3 reactor buiding
TEPCO announced completion of covering the floor by putting steel plate
for shielding to reduce the dose rates, after the unsucessful removal of
debris and dusts by employing a robot. By using a forkift with a shielded
cabin, they placed 51 steel sheets in double, where each steel sheet is of
the size of 3 m x 1.5 m with a thickness of 2 cm, yesterday. Today, they
inserted steel strips between the joints. After this operation, the dose
rate was decreased to 0.2 mSv/2.5h. TEPCO showed a photo as attached. To
further reduce the dose rates, "lead wool" mats will be laced on top of the
steel plates.

II. A low injection flow alarm in 1F1.
The flow rate in 1F1 started to decrease, spontaneously, from thecurrent flow setting at 3.7 m3/h since 9:00 PM on yesterday until soundig a
low flow alarm of 3:00 m3/h, at 8:13 AM today. At 8:40 AM the flow rate was
increased to 7:5 m3/h for ten minutes and returned back to 3.8 m3/h. No
root cause of this mysterious phenomenon has been identified yet.
Athough TEPCO explained that this phenomenon may be due to some
impurities in the injected water, it is difficult to account for the
observed gradual increase in the flow resistance. There can be due to a mass
transfer or deposition of corrosion product through some change in a water
chemistry configuration after the re-cycled water injection. There is a
similar occurrences in more than a dozen of PWs, during a normal operation,
called "axial offset anomaly (AOA)". In this case, corrosion products moves
from an anodic location to a cathodic location, induced by radiation
chemical process. ( G. Saji, 2006, A Root Cause Study on AOA-PWR and
CDA-VVER: A Point of View of ŒLong-Cell Action¹ Corrosion Mechanism,
ICONE14-89658)
In some cases, the fuel channels were clogged with the corrosion products,
resulting in fuel failures in VVERs.
If this mechanism is in place, the following scenario can be idntified.
(1) The oxygen concentration of the recycled water became much lower than
the "filtered" river water, since the water treatment is performed in a
closed tanks under high radiation, reducing the dissolved oxyn back to
water.
(2) The resultant water chemistry (redox potential) became much lower in the
reactor vessel. This resulted in removal of passive oxide film from
stainless steels, resulting in rapid dissolution of metals into the reactor
water.
(3) With high radiation in the core region, the redox potential becomes more
cathodic, inducing deposition of corrosion products in the cooling channels.
To prevent this situation, it is better to saturate the recycled water
with air, since the "filtered" river water did not induce this kind of a
strange behavior, in my understanding. Anyway, with longer water cooling,
the water chemistry control is also becoming important for preventing
"channel blockage" accident as occurred in the VVER reactors, Loviisa and
Paks.

III. Recapping on pipe rupture in the 1F5 temporary installed se water hose
The reactor cooling was suspended for 3.5 hours yesterday, due to a
"hose rupture" accident occurred in the 1F5 temporary installed sea water
hose. TEPCO concluded that the rupture is due to sharp bending. TEPCO
intend to identify all such locations and replace the relevant hoses.

Well, let me stop here tonight!


Genn Saji
_________________________________________________________________________
(Previous e-mail sent at 10:40 PM on July 3 as Earthquake (114))
Dear Colleagues:

114th day!

I. Recapping on cleaning of debris from the 1F3 reactor building.
TEPCO introduced a new robot to clean up debris from 1F3 ractor building
on July 1. Through 5 hours of operation, three drams full of debris were
collected, howeverthe follow on dose measurement showed reduction of only
10-20 mSV/h.
Tay TEPCO released a dose map measured on July 2 as attached (in
Japanese).
http://www.tepco.co.jp/nu/fukushima-np/images/handouts_110703_01-j.pdf
In the map, the green shaded zone is where the cleaning operation has
been perormed. The dose values in parenthesis indicate the value measured
on June 24and the new values taken on July 2 are shn outside.
TEPCO is trying to reduce the dose rates by putting steelplate for
shielding. This information indicates that a significant rdioactivity
contaminations exist on the floor surface. In this kind of situation, a
standard procedure is decontaminatin by using reagent. However, such
operation seems to be judged impossible n view of very high dose rates.
Moreover the high dose rates in this reion is very likely due to a
leakage from the ECCS piping running upward inide the rectangular shielded
compartment connecting the suppression pl to the RHRS heat exchangers.
Since the water leakage is observed, the brak is on the upper floors. The
re-circulation pumps are also located in n upper floor of this zone. A pipe
break in a branch of ECCS pipes occurrd at Hamaoka Unit 1 during normal
operation due to "internal hydrogen explosin."

II. Pipe rupture in the 1F5 temporary installed sea wer hoses
A temporary installed hose was found broken, gashing sa water. I am in
serious doubt that these flexible hoses for ordinary costruction work can
be applied for RHRS type safety grade systems. At let, such a flexible
hose should be applied with sufficient structural margi from their catalog
maximum pressure rating.

III. Recapping on release fractons
In Earthquake (107), I introduced an assessment on "Significant
Radiactive Species" that are likely released to the highly contaminated
water. Let me update this, since I discovered an error in the estimate for
1F3 asattached. I have been trying to expand this methodology to estimate
the mostlikely fraction of radionuclide that were released to the RPV/RCV
as well aseffluents to the atmosphere as attached.
Since robust data for thiskind of study are very limited, the predicted
atmospheric release fraction o 1.5% for Cs-134+Cs-137 is close to the other
estimation obtained through a land contamination map provided by the US
DOE/NNEA dose map data, yielding2.4%. I claim the difference supports an
existence of the "internal hydroge explosion" releasing a small amount of
radioactive species directly into te atmosphere, without going through the
suppression pool water, thus evading DF of more than 100.

Well, let me stop here tonight, Sunday night!

Genn Saji
________________________________________________________________________
(Previous e-mail sent at 10:42 PM on July 2 as Earthquake (113))
113th day!

Dear Colleagues:

I. Recapping on societal risk of evacuation
The Yomiuri newspaper made a survey of mortality rates of aged evacuees
being cared in senior nursing homes for elderly people, within 30 km zone.
There were 15 such homes. The government first ordered to evacuate within 3
km zone on March 11, which was expanded to 10 km first and enlarged to 20 km
on March 1. On March 18, the government requested to evacuate these
facilities located with 20 to 30 km zone.
Within 3 months, 77 senior residents passed away. Seven of them were over
100 years old, 46 above 90 years old, 19 above 80 years old, 4 over 70 and
one over 60 years old. Last year, 25 residents passed away. This indicates
that the mortality rate was 3 time higher. The serius question is whether
the reduction of radiation risks by evacuation really warrants the
inevitabe societal risk induced by the evacuation.

II. Recapping on the water purification system
TEPCO announced today that they could successfully switch to the
re-cycled water from the filtered river water they have been using after terminating the sea water injection. Although they have started the water re-circulation on June 17, it was limited only partially. TEPCO now has a
stock of 3500 tons of desalinated water, sufficient for the war injection
for more than a week. They also has a stock of around 11000 tons of
decontaminated sea water, waiting for desalination. The current
availability of the water purification system was down to 60%, they hope to
improve it to 80% soon.

III. Capping on cleaning of debris from the 1F3 reactor building.
TEPCO relesed a new photo of the robot working inside of 1F3. Please
visit: http://ww.tepco.co.jp/en/news/110311/ndex-e.html and download
Cleanup work by using a robot in Unit 3 Reactor Building at Fukushima
Daiichi Power Station
Through 5 hours of operation, three drams full of debris were collected,
however the follow on dose meurement showed only 10-20 mSV/h. It is
explained that only an entrance region was cleaned, resulting in not
substantial improvement. One of the main objectives of cleaning operation
is to facilitate nitrogen gas injection nto the containment vessel to
prevent another hydrogen explosion.

IV. Recapping on air cooler installed in 1F3.
The pool water temperature went down to 39.9? today at 5:00 AM, from the
62? when started at 8:30 AM of June 30. Also the debris removal and vacuum
cleaning operation has completed for the 100 m2 first floor of 1F3 Reactor
Building.