Fukushima: day 121 to 130

Dear Collagues:

130th day!

I. Ending the Step 1 of Roadmap and started Step 2
TEPCO issued a revised roadmap, which contains some interesting points:
(1) The goal of step 2 is to decrease the release of radioactivity to less
than 1 mSv. At the time of the accient, on March 15, the release rate was
as high as 2 PBq/h. This has wen down to 1 GBq/h, which can be converted
to 1.7 mSv of an accumulated dosenear the site boundary, at the end of
June.
(2) The interpretation of "cld shutdown" is (i) the temperature at the
lower portion of reactor vessel sould be below 100?, and (ii) the
additional release of radioactivity is redued substantially, less than 1
mSv/h. This will be achieved by improving th cooling capability of the
reactors through the re-cycled water injection an air cooling system.
(3) Mid-term decommissioning planning. Please note" [Action towards the
mid-term issues] The government will develop a mid-tem safety issue and
TEPCO will develop a plan based on this policy.
Engish version is now posted at:
http://www.tepco.co.jp/en/press/corp-com/releae/11071905-e.html
Press Release (Jul 19,2011)
Progress status of "Roadap towards Restoration from the Accident at
Fukushima Daiichi Nuclear Powr Station" on July 19

II. Update of internal exposure in live stocks In view of unexpectedly widespread of radioactive cesium contaminaed
beef to almost entire Japan, the government announced the followingtwo
things:
(1) Restriction of marketing beef cattle from Fukushima Prefeture on the
basis of Law of Countermeasures against Nlear Disasters. This restriction
will be continued until Fukushima Prefectre provides a new individual
cattle chking procedure which will not result in diffusing the
contaminated bee to the consumer.
(2) Nation-wide tracing of the contaminated rice strw feed, especially
those supplied from Fukushima
Fukushima was a lare supplier of rice straw feed, as an substitute of
hey, because this are is relatively dry during the winter seasons, compared
with the wesern snowy regions. After clopping the rice, the straw is
usually coected during the winter season and stored in wrap silage in that
district and old to ranches throughout the eastern Japan. It appears that
rice straw feedhas been contaminated during that process in the field.

Well, let me stophere tonight,

Genn Saji
___________________________________________________________________________
(Previous e-mail sent at 0:55 AM on Jul 19 as Earthquake (129))
Dear Colleagues:

129th day!

I. Update ofinternal exposure in live stocks
The most recent statistics revealed tht a total of 578 meat cattle were
fed with radiation contaminated traw and most of them have been already
consumed widely. The Government i reported considering to restrict
marketing meat cattle from Fukushim Prefecture, Currently the following
issues are being discussed.
(1) Is tere more reliable methodology to screen the level of contamination
in mea by some kind of biological examination (e.g. Urine analysis).
(2) How to develop a practcal method of screening, which is more likely
screened through meat sampls of all meat stock in Fukushima.

II. Update of the water purification sstem
On July 17, another event of gradual decrease in the flow rates f water
injection line occurred in 1F1. This is the third times, thelow flow rate
alarm indicated lower than 3 m3/h. Suspecting a failure of ne of the
redundant pumps, TEPO switched to another pump also by increasing the flow
rate to 3.8 m3/h.
I have been suspecting it is due to de-passivation, dissolution at
anodic meta surface then transported with flow to and re-precipitate at
more cathodic egions or at filters, clogging the coolant flow passages.
The issue has many common mechanisms as occurred in AOA, (axial offset
anomalies), whch occurs in very anodic water chemistry combined with a
mechanm of "macro cell" corrosio9n mechanism. A water sampling and
chemical aalysis will clarify this when an iron particulate concentration
is high, typially several micrograms/kg-water. See, for example R.J.
Rosenberg et al., Irn Deposition on the Fuel Assemblies of the Loviisa 2
VVER-440 Reactor, p. 475, 1998 JAIF Int. Conf. water Chemisty in NPP, Oct.
13-16, 1998, Kashiwazaki, Niigata, Japan. G. Saji, 2006. A Root Cause Stud
on AOA-PWR and CDA-VVER - A Point Of View of ³Long-Cell Action² Crrosion
Mechanism -, ICONE14-89658, Miami, Florida, USA.

III. Updat on preparing for a potential approach of Typhoon #6.
More detailed expanation was made that the temporally roof will be
constructed on a portion f the turbine building which was destroyed in the
wake of hydrogen explosio. An elliptical hole of 11 x 14 meters were blown
away. Although some meia made an explanation that it is due to falling
debris ejected from the hydrogen explosion of 1F3 building, some scientists
are suspecting it is due to another hydrogen explosion through leakage of
hydrogen gas in the turbo-generator.
The temporary roof consists of three steel panels, each of a size of 5 x
16 meters. By using a remote crane, TEPCO anounced that the construction
was started at 8:30 AM and completed by 14:40 PMthis afternoon. A photo is
posted in http://www.tepco.co.jp/en/news/11031/index-e.html . Please
download " Fukushima Daiichi Nuclear Power StationUnit 3 Turbine Building
Installation Work of Roof (pictured on July 18, 2011 "
During the construction work, four workers had to assist on top of he
roof. Since it took more time than anticipated, two of them exceeded anaccumulated dose of 10 mSv, the maximum was 12 mSv, six times more than thelanned 2 mSv.
Smaller holes are also being planned to be covered on tomrrow, July 19.

Well, let me stop here tonight,

Genn Saji
____________________________________________________________________________
(Previou e-mail sent at 0:41 AM on July 18 as Earthquake (128))
Dear Colleagues:

128h day!

I. Update of internal exposure in live stocks
I introduced this isue two days ago in Earthquake (126). This issue
began to spread much wider rea, since Fukushima Prefecture is checking the
radiation contamination o straw among the entire ranch owners.
The most recent statisti revealed that a total of 143 meat cattle were
fed with radiation contaminate straw and most of them hae been already
consumed in widely. I am puzzled with the spread of locaon of the
contaminated beef stocks. The first inspection made on Jue 15 was
understandable since the ranches were located at the edge of highy
contaminated areas (Minami-Soma-shi, 17 stock and its north, So-ma-shi,
stock). However, the new districts reported (Kooriyama-shi Kitakata-shi)
hav not been recognized as contaminated areas, being 1.0-1.9 microSv/h,
accordng to the aerial observations made by DOE/NNEA. These areas are
located were the rice feed samplinghowed very high dose rates, as high as
100,000 Bq/kg. There is a possibilty that the rice straw stored in racks
in the paddy fields may filter ad concentrate the atmospheric
contamination, resulting in much higher doe level than soil contamination.
This effect needs further study.

II Approaching at the end of Step 1 in the Roadmap
At the end of three monhs after the inauguration of the road map,
politicians are addressing ther view that the "stable cooling" and "no
hydrogen explosion risk" haveeen achieved. It seems to imply that the
damaged plants are all cloe to a "cold shutdown", although there is no such
definition for sevee accidents.
This is more like a political explanation, and I still thin recovery of
the closed cycle cooling is still indispensable for the "stabe cooling".
Although the water injection utilizes mostly the recycled wate, the
residual heat is still removed by evaporating a part of the injected ater.
The resultant steam generation should be accompanied with a substntial
amount of radioactivity, whh is still being released to the environment.
However, when the air-cooler are installed in these tee units, this
evaporation pathway will become a several orders of magnitude lower in the
environmental release of radioactivity even without recoveing the secondary
confinement systems, called "covers." Therefore, I am relutant to say that
the "cold shutdown" state has been achieved within the Step 1 of the Rad
Map.
The government intends to slack the Emergency Preparedness Zone when
the "cold shutdown" state is established as well as survey of local ose
rates became low enough to coinue staying in that zone. This seems to
imply that an accumulated doses should be below 20 mSv.

III. Preparing for a poential approach of Typhoon #6.
Currently a big typhoon is approachng to the Japanese islands. Verious
countermeasures are being performed. mong them, TEPCO is preparing a
temporally roof fo 1F3. A photo of a stockyard is posted, showing parts
are now ready. http://www.tepco.co.jp/en/news/110311/index-e.html "
Please visit " Appearance of the Roof for Countermeasure against Rainwater,
Unit 3, Fukushima Daiichi (pictured on July 17, 2011)
It appears that these parts will be soon put together o top of 1F3 within a
few days.

Well, let me stop here tonight.

Genn Saji
_____________________________________________________________________
(Previous e-mail sent at 11:36 PM on July 16 as Earthquake (127))
ear Colleagues:

127th day!

I. Video of 1F2 Reactor Building
TEPCO relased a new video taken by Qunce (recently commissioned
Japanese robot, assmbled by Chiba Institute of Technology) in their
website:
http:/www.tepco.co.jp/en/news/110311/index-e.html
(since the WMV file is 1 MB, I cannot attach to this e-mail)
Please download "Investigationof the status in the Reactor Building, Unit
2, Fukushima Daiichi Nuclear ower Station by Quince(ZIP 18.1MB)
(videoed on July 8, 2011)"
The robo has a capabilities to climb up the stair cases, to take very
clear wide-angle video as well as to take water samples. I was a bit
surprised to find tha upper portion of the reactor building is very clean,
without debris in 1F2. Also, there are some shots showing dark brawn large
spots, perhaps indicating leakage of the reactor water containing hematite
(Fe2O3) with its water dried out, if thoe dirty spots were not there before
the accident. This may help us to furter investigate a potential damage
location of the reactor pressure vssel, reactor containment vessel or
piping. I hope TEPCO will pay attntion to these foot prints for
identification of the location of leakages. Tis task is included in the
roadmap but no progress has been made since May.
I. Update of the water purification system
TEPCO also released (in Japaese) a schematic illustration of the part
of the system that is not workingat the full capacity.
http://www.tepco.co.jp/nu/fukushima-np/images/handouts110716_01-j.pdf

At 5:00 AM on July 16, the system was stopped operation forrecover the
decreased flow rate potentially due to air pockets. The systm re-started
again at 2:00 PM but no improvement was made in the apacity.
From the illustration, I noticed that the problem occurred outsie of
the AREVA's co-deposition system, rather in the treated water transfe
system to the storage tanks. Although TEPCO seems to attribute the rouble
to potentially forming air pockets, I believe this is more likely due o
crystallization of dissolved iron in the treated water. The dissolved ionis a kind of corrosion process when the electric potential is very anodic
As a matter of fact there are sacrificial electrodes shown in the
illustraton likely for cathodic corrosion protection. TEPCO removed the
electroes to reduce the pressure loss, however, it is not good for
prevention of orrosion.
I think this is a generic issue for the water purification ystem for
the highly contaminated water. With high radiation, the disolved oxygen
from the air is reduced back to water, lowering the redox potetial. The
sacrificial electrodes should have been to ameliorate this elctrochemistry
configuration. When the redox potential is very low, the watr removed the
passive protection film from the metal surface inducig the metal to start
dissolving into the water. The dissolved iron, forexample, will crystallize
at a cathod region, resulting in plugging. As a matter of facts more than
a doen events has occurred in VVER as well as PWR plants, including in
Luviis in Finland as well as in Paks in Hugary. In both plants, the fuel
cnnels were plugged with dendrite crystals of iron and oxide. To prevent
this, it is necessary to recover the dissolved oxygen concentration.As a
matter of fact, so-called "oxygen pre-filming" is a standard startup
rocedure for BWRs, in my understanding. This process was invented y my
fried from Hitachi. I think the reason for decrease in the flow rat is
likely induced by plugging the "filter" placed in a feeding line fro
AREVA's second co-deposition tanks. It appears to be necessary to add aair
bubbler between the Kurion's and AREVA's system to improve the overall wter
chemistry of the purification process as a whole. With an unprecedentedong operation, water chemistry of the total system is becoming a very
imortant task.

Well, let me stop here tonight. "Riho-chan", my almost 30 onths old grand
daughter, is staying with us for coming two days. Her moter'a company is
running both on Saturday and Sunday during the summer seaon, due to
shortage of electric power supply. She is expecting her grnd par (it's
me!) to be her play mate while she is awake. We play house

Genn Saji
______________________________________________________________________
(Previous e-mail sent at 11:58 PM on July 15 as Earthquake (126)
Dear Colleagues:

126th day!

I. Update of the "Stress Test" for all NPs in Japan
NISA submitted their planning of the "stress tests" to NSC. I is
posted by NSC (in Japanese) in the website:
http://www.nsc.go.jp/anzn/shidai/genan2011/genan053/siryo1.pdf

It is a rather complicated guieline but some of the notable points are:
(1) Scope
All NPPs, including hose under construction, to be followed with
another guideline for nuclear fuel cycle faciliies.
(2) Postulated initiating events
Natural phenomena: earthquake and sunami (Superposition of these two in
the step 2.
Loss of afety functions: "station blackout" and "loss of ultimate heat
sink"
(3) Assessment steps
Step 1: Assessment of safety margins againstBDB events. Confirmation of
additional safety margins in view of "defene in depth" for BDB
provisions
Step 2: Resilience of the plants aginst severe events, in preventing
gross failure of fuels.
(4) Procedues
?Event sequences: Results in an event tree format.
?nsideration of time sequence as well as necessary time duration for
accident management.
?Superosition of "station blackout" and "loss of ultimate heat
sink" fr step 2.
?Should consider the effects of additional safety features
?Deterministic, best estimate assessment
(5) Planning
Step 1: Those plats ready for re-starting
Step 2: By the end on this year, while adating findings made in the
European stress test. NISA may revise th current planning.

II. Update of the water purification system
It as reported that the high dose rate work for fixing the plastic hose
join was performed by 10 workers, limiting each one of them exposed within
two inutes of work. The system went back to operation at 6:30 PM on Jly
14, however, TEPCO was puzzled with an expected low flow rate capped withonly 80%. At 5:00 AM, the system was stopped operation for a potentia air
pocket. The system re-started again at 2:00 PM but no improvemet was made
in the capacity. Durig these outage times, TEPCO was using the treated
water stock, which was runing low. TEPCO added 570 tons of the filtered
natural water today, he first time in the last two weeks.
Currently, TEPCO is constructin a backup water purification system. The
first shematic illustration was posted in the TEPCO website, although only
in Japnese,
http://www.tepco.co.jp/nu/fukushima-np/images/handouts_110714_06-j.pdf
The system is an improved version of Kurion's system, by optimizing the
sobers to provide mre event sorption.

III. Nitrogen gas purging into 1F3 RCV
TEPCO began t be puzzled in essentially no pressure increase after
sending 200 m3 of itrogen gas into the 1F3 containment vessel, very likely
due to a large lak hole.

IV. Update of internal exposure in live stocks
This issu began to spread much wider area, since Fukushima Prefecture
is checking te radiation contamination of straw among the entire ranch
owners. It ws not limited to the house grown straw but also those purchased
from mch wider region. I believe it is due to storing straw in
the fiel at the time of plume passage during the first week of the
accident, in paricular due to the "black rain".

Well, let me stop here tonight!


Genn Saji
_____________________________________________________________________
(Prevous e-mail sent at 11:16 PM on July 14 as Earthquake (125))
Dear Colleagues:
125th day!

I. Nitrogen gas purging into 1F3 RCV
TEPCO announced todayat 8 PM that the nitrogen gas purging has started
in 1F3 Reactor Conainment Vessel and currently its operation is being
closely wathed With this operation, now all three units, 1F1 - 1F3, are
now going to be provided with the nitrogen gas atmosphere. This should
reduce a risk of potential hydrogen explosion.

II. Update of the water purification system
Yesterday, at one PM, another water leak occurred in the AREVA's
co-deposition facility. A plastic hose jointnozzle was found broken. By
replacing it with a stainless nozzle, he system went back to operation at
6:30 PM today. The system was out f service for more than a day. Due to
this break, the dose rates was repored to be as high as 100-150 mSv/h. The
worker dose is my concern with workng in such a hostile radiation
environment.

III. Worker doses since March-pril at Fukushima
TEPCO announced a statistics of worker doses accumulate for those
started to work since March-April. Among the 6792 workers, the acumulated
doses more than 100 mSV were 111, including six of tm who exceeded 250
mSv. There remain 132 workers who have not responded o the radiation
health follow-ups being performed by TEPCO, as well as additonal 1542
workers whose internal exposure has not been examined yt.

TV. Update of the "Stress Test" for all NPPs in Japan (Part 2)
Attachd please find the second part of the accident scenario revisited.
I intend o write the third part in the near future.

Well, let me stop here tonight!

enn Saji
__________________________________________________________________
(Previous e-mail sent at 11:35 PM on July 13 as Earthquake (124))
ear Colleagues:

124th day!

I. Update of the water purification system Another leakage occurred in AREVA's co-deposition process, leakng 5
liters. TEPCO id trying to replace the PVC hoses into a stainss hose
jopint. Because of frequent stop, the availability went down to 73% not
improving for the last two weeks.
Since many temporary PVC hoss are used for accident management, it is
becoming increasinglyimportant to replace them with more robust materials.
Today, at 1F5, the reactor cooling was suspended for 4.5 hours to replace a
hose. During that eriod, the reactor water temperature increased by 7?,
although it was till in the cold shutdown state at around 50?.

II. Internal exposure in ive stocks
The further investigation by the Fukushima Prefecture reveled that the
internal exposure is through the the house grown dried rice sraw, which
were stored in paddy fields. With th finding, Fukushima Prefecture has
started to investigate the radiation conamination of straw among the entire
ranch owners. It was reported that the frmer had to feed with straw, since
the distribution company refused to visit his ranch for one month soon after
the earthquake. The local government is tying to butcher all the live
stocks within the Emergency Preparedness Zoe and screen the meat before
distribution.

III. Update of the "Stress Tst" for all NPPs in Japan
Currently, NISA is developing a guideline forthe first stage of "Stress
Test". It is reported to includes safety asessment of beyond design basis
earthquake, tsunami, superposition ofthe earthquake and tsunami, etc. It
is reported that NISA will report tothe Nuclear Safety Commission by the
end of this week. It has been taking aslong as a few years for the full
set of regulatory reviews, consisting of ISA review followed with NSC
review, further followed with agreement with lcal governments. Since the
scope of safety assessment is limited, the new reew procedure should be
performed in due time, I hope.

Well, let me stop her tonight,

Genn Saji
____________________________________________________________________
(Previous e-mail sent at 11:30 PM on July 12 as Earthqake (123))
Dear Colleagues:

123rd day!

I. Update of the "Stress Test" fo all NPPs in Japan
As anticipated, reactions against the "unified Gvernment's policy",
without technical details nor supporting planning, invted a wide-spread
criticism from local government chiefs and mayors as well a media reports.
Since the Democratic Party of Japan was elected b a majority on August
30, 2009, the new Government is trying to control the breaucrats and they
have kept a style to have their own decision independent from the
bureaucrats. Therefore it appears that this kind of rle making, first by
politicians even without technical basis, is not strang for the ruling
politicians.
Going back to the "Stress Test," I believe it is essential to understand
the Fukushima Daiichi accident sequences from a scientific point of view.
Therefore, let me try to update the accident sequence on the occasion of
four months after the initition of the accident sequence. I proposed the
"stress test" in a "listof lessons learned from the Fukushima Daiichi
accident" introduced fir in Earthquake (26) on April 4, based on a sketchy
information available at that time. Since many new information became
available as to the root causes of this accident, it might be an appropriate
timing to revisit this issue.
Attached please find a rather lengthy memo. I intend to write the
second part in the near future.

II. Update of he water purification system
Another leakage occurred at the same locaton of the AREVA's
co-deposition tank at around 8:40 AM today. The leakage wa due to
corrosion of the metallic part. At 5:00 PM, the system went back to
peration, after replacing the pipe joint with a stainless steel parts.

III. Nitrogen gas purging line completed.
Today the installation of the nitrogened by
just a 15 minutes of work inside the 1F3 Reactor Buildingstable.

IV. Update on internal exposure likely in live stocks

Wight!


Genn Saji
_______________________________________________________________________
(Previous e-mail sent at 9:48 PM on July 11 as Earthquake (122))
Dear Colleagues:

122nd day!

I. Update of the "Stress Test" for all NPP, Chief Secretary of State, made a press interview, to
explain policy on the re-starting of the Genkai
NPPs, waiting for re-starting by finishing the schedulencement was explained without handout. He explained an outline of the
Government policy as below.
(1) A new sfety evaluation should be performed under a new procedure and a
rle, by referring to the "stress test" initiated in EU.
(2) Items andplanning of safety evaluation should be developed with a
confirmation of theNuclear Safety Commission (NSC). The power companies
should perform relvant safety evaluations, which should be reviewed first
by NISA and shuld be doubly confirmed by the NSC.
(3) Safety evaluation should be performed in two stages. The first stage is
for judgment of adequacy of re-starting from the maintenance outage. This
should clarify safety margins beyond licensing bases. The second stagluation for currently operating fleet for judging
either continon.
It appears that technical details will be developed from nongly uncertain whether the NPPs will ever be able to restart
in due time for the smmer peak load.

II. Internal exposure through inhalation likely in live scks
As introduced yesterday that beef cattle recently allowed to start
mrketing from the a ranch located in the 20-30 km "Emergency Preparedness"
zoe was rejected at butcheries by detecting as high as 23,000 Bq/kg of
radioacive cesium in the meat sample. A further sampling examination of the
fee and underground water revealed that the house grown dried rice straw
wastored outside and showed high radioactive cesium contamination, as high
as seeral tens of thousands Bq/kg. Thtemporary guideline is 500 Bq/kg.
Depending on mixing ration of this fed stream, the internal explosion can
also be from the feed chain. In view f the internal exposure concern, the
Government is requesting to start total screening policy.

Well, let me stop here tonight,

Genn Saji
__________________________________________________________________________
(Previous e-mail sent at 7:28 AM on July 11 as Earthquake (121))
I found I frgot to send this e-mail last night. I regret for your possible
inconveniece, if any.

Dear Colleagues:

121st day!

I. Internal exposure through inhaation likely in live stocks
Beef cattle recently allowed to start marketng from the a ranch located
in the 20-30 km "Emergency Preparedness" zonewas rejected at butcheries by
detecting as high as 23,000 Bq/kg of radioacive cesium in the meat sample.
The ranch was raisincattle in a barn, feeding them by imported assorted
feed, imported as ell as their house grown dried rice raw and supplied
with the underground water for drinking. The local inspectrecently
allowed marketing live stock in the market, after going through he
screening test, which measures only the surface contamination level of
livstock. If the cattle was not out to the field at the time of plume
passag it is likely the radiation exposure is through inhalation pathway.
t was too bad that detailed distribution of radiactive species were not
measured, since the cattle could have provided an excellent sample for
radiological health study.

II. Update of the water purificationsystem
At around 5:00 AM, minor leakage of approximately 50 liters, occured at
the AREVA's Co-deposition process, resulting in shutdown of the water
purification system, however, the water injection continues by using treated
water stored in buffer tanks. The leakageoccurred in the chemical feed
hose to the co-precipitation tank as shown in the attached photo posted in
http://www.tepco.co.jp/nu/fukushima-np/images/handouts_110710_02-j.pdf By replacing into a flexible metal pipe, the plant went back to the
operation at 5:40 PM. Since the radiation was at the same level of the
water being processed, the leaage of the process water was also likely.

Well, let me stop here tonight,

Genn Saji