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Fwd: Criticality Accident, Updated Full Summary, 991013 23:20 MDT
Below is the latest summary of the criticality incident that was send out
to the criticality safety email list last night.
Mike ... mcbaker@lanl.gov
>From: "Valerie L Putman" <VPUTMAN@inel.gov>
>To: vlp@mr-ed.inel.gov, "Felix Killar" <fmk@nei.org>
>Date: Wed, 13 Oct 1999 23:48:49 -0600
>Subject: Criticality Accident, Updated Full Summary, 991013 23:20 MDT
>
>
>
>THERE WILL BE A SPECIAL SESSION ABOUT THIS ACCIDENT AT THE
>ANS WINTER MEETING IN LONG BEACH, CALIFORNIA. Sponsored by
>the Nuclear Criticality Safety Division, the session is tentatively
>SCHEDULED FOR 4 to 6 p.m., MONDAY, NOVEMBER 15, in CONVENTION
>ROOM 104B OF THE LONG BEACH CONVENTION CENTER
>
>
>=================================
>30 SEPTEMBER 1999 CRITICALITY ACCIDENT
>SUMMARY TO DATE (991013 23:20 MDT)
> Prepared by Valerie L. Putman,
> INEEL/BBWI, Criticality Safety
> vputman@inel.gov
> please send additions, corrections, comments
>=================================
>
>DISCLAIMER: This summary is an in-progress work. It includes
>additions and corrections to previous summaries. Information
>is based on a copies of somewhat technical Japanese presentations
>made in Europe, news articles, internet postings, other's
>experience with fuel fabrication in the U.S., and email messages
>from technical personnel who are not directly involved with the
>incident, incident response, or incident investigation. Some
>information copies are poor quality, with much information blurred
>due to size and/or the copy generation. Available news articles
>are mostly non-technical, often sensationalized, and sometimes
>contradictory, as expected. In addition, there are some questions
>arising from different nomenclatures and possible translation
>problems.
>
>
>BACKGROUND EMAIL INFORMATION
>
>For convenience,
>- low enriched uranium (LEU) = less than 10% enriched
>- intermediate enriched uranium (IEU) = 10-60% enriched
>- times are Tokaimura local and specified in a 00:00 to 24:00 format
>- uncertain and speculative information, and comments, are marked,
>often with brackets ([]) or question marks (?).
>
>To avoid limits of some email software, this message has
>no attachments, is in US ASCII, has a very long bcc list,
>and will be divided into parts (source citations, URLs, and
>graphic files were, or will eventually be, sent in separate
>messages)
>
>Radiation dose values:
>- 1Sv = 100 rem [I do not know any exposure values in Gy or rad,
>neutron spectra for the various exposures, or contributions from
>neutrons and gamma rays for most exposures]
>- 20mSv is worker annual dose limit, according to JCO presentation
>- 7Sv is considered lethal, according to interviewed Japanese
>medical personnel [some radiological specialists say 7Gy, not 7Sv]
>- 0.25Sv is usually the point at which some radiation sickness
>symptoms are expected, according to interviewed Japanese medical
>personnel [some radiological specialists say .25Gy, not .25Sv]
>- 1Gy = 100rad
>
>The regulator, Science and Technology Agency (STA), is web-posting
>information in Japanese at URL
> http://www.sta.go.jp/genan/jco/jco.html
>STA also posted some of this information in English at URL
> http://www.sta.go.jp/genan/jco/jco-e.html
>Thanks to Enrico Sartori, I separately sent pdf files of much of
>the Japanese material, translated into English. These files were
>scanned-in, black-and-white versions of an STA/JCO presentation at
>a joint IAEA and OECD meeting. Presentation materials include an
>apparent confusion between UO2 and U3O8. According to presenters,
>units listed as Sv are actually Gy [another
>translation/transcription problem?]
>
>Many thanks are due to many people who forwarded information,
>corrections, and translations. They will be listed in the source
>citations to be sent later.
>
>=======================================
>
>
>INTRODUCTION
>
>A criticality accident occurred at 1035 on September 30, 1999. It
>occurred in a Conversion Test Building of a nuclear fuel fabrication
>facility in Tokaimura (Tokai Village), about 140km (75miles)
>northeast of Tokyo, in the Ibaraki Prefecture. STA provisionally
>rated this accident a 4 on the International Nuclear Event Scale
>(INES). Their basis was radiation exposures to two operators and to
>two off-facility people. However, on October 7th, authorities were
>considering rating the accident a 5 based on accident causes as well
>as on radiation exposures.
>
>
>THE FACILITY AND OPERATIONS
>
>The facility is part of JCO Co.'s Tokai Works site, which in turn
>is one of 15 nuclear sites in Tokaimura, a city of about 34000
>people. The entire facility is unshielded because process material
>is unirradiated or "cleaned" of fission products. The plant had no
>criticality accident response plans or criticality accident alarm
>systems because it was assumed "critical fission chain reactions
>could not occur." [More probably, "Emergency planning was not
>required because management and authorities assumed a criticality
>accident was not credible if an appropriate criticality safety
>program was implemented."]
>
>Granted when JCO Co. was known as the Japan Nuclear Fuel Conversion Co.,
>the plant license apparently predates Japan's Science and Technology
>Agency's (STA's) guidance that licensee's should assume a criticality
>accident is possible when enrichments exceed 5%. Apparently there were
>no STA inspections, periodic reviews, or means to enforce new guidance.
>Nor were there any regulations or other requirements for such. [Power
>reactors received more attention, not unlike the focus of IAEA and
>many nuclear regulators since the Chernobyl accident.]
>
>Small radiation doses to workers were considered credible because the
>subject area has gamma-ray monitors. Apparently JCO has no portable
>neutron monitors, unlike other nearby nuclear facilities.
>
>The nearest site boundary is rather close to the subject building. A
>public road is within 80m. A building identified as a private
>residence is no more than 110m from the test building.
>
>This plant usually converts UF6 to UO2 for LEU (5% max.) commercial
>power plant (PWR and BWR) fuel. However, it occassionally converts
>U3O8 to uranyl nitrate for about 20% IEU MOX and breeder reactor fuel.
>This accident involved 18.8% IEU, processed to produce uranyl nitrate
>for JOYO, a fast breeder research reactor.
>
>A manual provides written instructions for all operations. Although
>both process apparently use some of the same equipment, operational
>limits differ for LEU and IEU enrichments. A 2.4kg uranium batch(?)
>limit applies to 16 to 20% enriched uranium.
>
>This limit seems to indicate operations are based on the criticality
>safety double contingency principle. The principle is stated in a
>Nuclear Safety Committee Regulatory Guide, issued by the regulator,
>Science and Technology Agency (STA). Apparently it is a requirement
>for nuclear plants where an unshielded criticality accident is
>considered credible. [However, remember this accident was not
>considered credible before September 30th.] The guide is in Japanese
>and, apparently, there is no English translation of it [yet]. [A clue
>to the principle's wording might be gleaned from the fact that a
>single-failure, rather than double contingency, principle apparently
>applies to uranium reprocessing facilties. I assume the single-failure
>statement is something like, "No single failure shall result in an
>inadvertant critical excursion."]
>
>The regulator-approved IEU process is shown schematically in STA/JCO
>gif files at URLs
> http://www.sta.go.jp/genan/jco/jco91008_3_2b.gif
> http://www.sta.go.jp/genan/jco/jco91008_2z1.gif
>This process starts out with U3O8 powder and/or nitric acid that might
>not be sufficiently pure. U308 powder is first put into a tower
>[headend tank]. Apparently tower feed-rate and a batch counter
>effectively limit uranium mass to help implement a 2.4kg uranium limit.
>The powder and nitric acid (HNO3) are fed into a dissolver vessel, from
>which uranyl nitrate solution or slurry (UO2(NO3)2) is pumped into
>18cm(?) diameter "Dissolver Product Extraction/Reverse Extraction Tanks"
>(also called buffer tanks in presentations) and then into similar
>diameter Storage Tanks. Apparently any mixing to this point is performed
>with air sparges, by sending air bubbles through these vessels. Uranyl
>nitrate from these storage tanks [columns] is then pumped to the
>subject sedimentation (precipitation) tank where ammonia (NH3) is added
>to precipitate ammonium diurinate (ADU, (NH4)2U2O3) [contaminates
>remain in solution]. Apparently mixing in this tank can be accomplished
>with an air sparge and/or mechanical stirrer. ADU is then processed
>[dried?,baked?] through "Combustion Chambers" to obtain U308, which is
>again dissolved in nitric acid in a [same,different?] dissolution tank
>and product uranyl nitrate solution is accumulated in [same,different?]
>storage tanks . Apparently this process can be repeated until an
>appropriate purity is acheived.
>
>Some years ago JCO approved a manual change, without STA authorization.
>This change accelerates the overall process. It allows workers to mix
>U3O8 powder and nitric acid in 10L steel [mop?] buckets. However, U3O8
>must be weighed to ensure compliance with the 2.4kg uranium limit.
>Three buckets of the resultant slurry or solution were then injected
>into a buffer tank [tower, column] and further mixing was completed with
>air sparging. Regulators say they would not have approved the change
>because uranium oxide and nitric acid in open containers, and their
>reaction, involve vapors [e.g. NOx] and readily airborne particles we
>should not breathe.
>
>Process acceleration was considered necessary to improve sagging profits.
>This sense of urgency was apparently felt by most workers
>
>A simlified mechanical drawing of the sedimentation tank is included in
>a pdf file emailed separately. Based on that and other drawings, the
>tank is primarily comprised of two vertical, axially centered cylinders,
>the smaller one on top, with no surface between the two (or alternatively,
>a cylinder which, at one point, has a flat shoulder where its diameter
>changes). Exposed portions of each cylinder top is flat, with nozzels(?)
>
>penetrating the flat top of the lower cylinder. The upper cylinder has
>a 22cm inner diameter, 30cm height, and, possibly, relatively easy-to-
>remove top. The lower cylinder has a dished bottom, 0.3cm stainless
>steel wall and bottom, 45cm inner diameter, 61cm inner height (flat top
>to lowest point in bottom), drain line in the bottom center, and
>horizontal lines [feed,outlet?] on the side about 20cm above the bottom.
>A 50cm outer diameter (or inner diameter of outer wall) water jacket
>surrounds the bottom and lower part of the tank (up to 35cm). Tank
>internal equipment includes a sparger and mechanical stirrer, which might not
>be present for all operations. In addition, one of the aforementioned
>nozzels apparently encloses an auger by which slurry or finely divided solids
>can be moved.
>
>A sketch of the accident building floor plan is at URL
> http://www.sta.go.jp/genan/jco/jco91008_3_8c.gif
>In table
>1. UF6 heating equipment (quantity: 2)
>2. UF6 water addition and separation equipment (quantity: 1)
>3. Dissolved product extraction equipment (quantity: 1)
>4. Dissolution equipment (quantity: 1)
>5. Sedimentation equipment (quantity: 2)
>6. Combustion (evaporation?) equipment (quantity: 1)
>7. Restoration (or return?) equipment (quantity: 1)
>8. Mixing equipment (quantity: 1)
>
>Words by equipment on the floor plan:
> 1 and 2 are "water addition and separation room"
> 3 and 4 are "conversion experiment room"
> 5, 6, and 7 are "sedimentation, combustion, and
> restoration (return?) room
> To the right of 1 is a UF6 storage room
>
>
>THE ACCIDENT
>
>The last campaign with IEU was about three years ago. The process
>was new or relatively new to all five workers assigned to it.
>Apparently this was either the first campaign, or first campaign with
>IEU, for two workers involved in this accident. In addition, this
>team's leader, had only a few months experience with the subject
>operation, with handling IEU, or both.
>
>Before the accident the team leader, possibly with lower management
>concurrence, directed workers to accelerate processing further by
>overbatching and by completing material mixing in the sedimentation
>tank, rather than in the buckets or buffer tower. He later stated
>they had done this before with no adverse consequences. [Reports do
>not indicate the extent or enrichment of previous overbatching.] He
>and/or management might have specified other shortcuts. The apparent
>end result was that U3O8 powder and nitric acid, or a concentrated
>uranyl nitrate solution, were added by funnel to the sedimentation
>tank directly through an opening made by removing a nozzel, cover, cap,
>or lid. Material was then mixed [continuously?, periodically?,
>sporadically] in the tank. These shortcuts apparently reduced a
>three hour task to 30 minutes.
>
>Interviewed workers and supervisors said they knew nothing about the
>dangers of overbatching. Some management personnel agreed, indicating
>worker training included almost nothing on criticality accident
>consequences and did not emphasize criticality accident prevention.
>
>On Wednesday, September 29th, work was delayed for at least five hours.
>Workers considered this delay serious, especially since intermediary
>U3O8 samples were due to quality control by that, or the previous, day.
>To make up for lost time, workers poured about 9.2kg uranium from four
>buckets into the sedimentation tank, before the work day ended. Still
>behind on Thursday, workers added about 6.9kg uranium from three buckets.
>Workers were most likely aware of the total accumulated mass. They
>were certainly aware of the mass accumulated Thursday.
>
>Workers added the last bucket contents about 10:35 Sept. 30th. The
>resultant solution, or reflected slurry, went flash [prompt?] critical.
>One email indicates the solution was approximately 370g/L uranium with,
>possibly, 1mole/L nitric acid. Another indicates a 360g/L.
>
>Contrary to earlier reports from other sources, a Japanese
>presentation indicates this system oscillated (or pulsed) between
>super- and sub-critical states for more than 17 hours. [If LANL's
>experience with the SHEBA solution critical assembly is indicative,
>there was little thermal energy in the system. It most probably was
>not boiling (perhaps a 10 degrees C delta) and pressure most probably
>increased by less than 10psi. However, there was probably significant
>bubble formation from radiolytic generation. As these bubbles form,
>the system goes subcritical and then critical again as the bubbles
>collapse. Much less likely, each pulse could have gone subcritical as
>boiling expanded the solution and converted some to vapor, then a new
>pulse would be initiated as the solution cooled and vapor condensed.
>Least likely, each pulse could have gone subcritical as solution was
>forced into lines connecting with the vessel top, and a new pulse was
>initiated as solution drained back into the vessel. Sparging or
>stirring and/or further U3O8 dissolution might have also contributed
>to the phenomena.]
>
>Available reports do not indicate the number of pulses, their magnitude,
>or their frequencies. Fission yields are not yet reported for any pulse
>or for the reaction duration. [Has anybody calculated these yields yet?]
>
>Tokyo Electric Power Company rushed some 880 lbs of borated material
>[boric acid?] to the JCO plant, apparently from their Tokai facility.
>However, responders could not use it right away because they had no
>readily apparent means of remotely adding neutron absorber to the tank.
>
>It took about 3 hours on October 1st to drain cooling water from a
>water jacket around the tank. At 02:35 two workers with radiation
>protection coveralls took pictures of a cooling-water-drain-valve
>outside the conversion test building. The area with the valve was
>highly contaminated [more probably, highly radioactive]. Although
>they stayed in the area only three minutes, one worker received
>11.92mSv gamma and 91.2mSv neutron. At 03:00 another two workers
>confirmed cooling-water-circulation-pump(s) functionality. At 03:22
>another two workers opened the valve. However, responders could not
>confirm water jacket draining. Finally, other workers cut a drain
>pipe outside, at the valve's up-stream side, and injected argon gas.
>At 06:00 responders confirmed the water jacket was drained. The tank
>was finally subcritical. Sixteen or 18 workers were involved
>in-field, draining this water jacket.
>
>Responders added borated solution [aqueous boric acid?] to the tank
>about 08:00 to further ensure system stability. These responders
>apparently found a funnel still in the opening through which workers
>earlier added materials to the tank. Borated solution might also
>have been sprayed into the room earlier.
>
>Nuclear Safety Commission (NSC) officials declared, "the criticality
>had ended for the time being," at 09:20 October 1st. Government
>[independent?,oversight?] officials confirmed system stability and
>an end to take cover measures at 15:00. However, responders continued
>radiation monitoring, and installed temporary shielding around some
>parts of the plant.
>
>The building was not physically damaged. Contrary to some
>non-Japanese reports, the building roof is intact. It is shown in an
>after-accident photograph at URL
> http://www.sta.go.jp/genan/jco/jco-e91007_3.html
>[There is a separate, nuclear fuel reprocessing plant in Tokaimura.
>It was fully or partially shut down after a 1997 fire/explosion
>accident. I think BBC's video of a building with a hole in its roof
>is actually file footage of this other plant.]
>
>[Most likely the tank was not damaged, especially since that funnel was
>still in place.]
>
>The entire plant/facility is shut down, with the possible exception of
>work to move licensed material [stored outside this area?] to other
>plants. As of October 7th, radiation levels were still too high to
>allow anyone into the immediate area [at least not for more than a few
>minutes].
>
>
>RADIOLOGICAL INFORMATION - exposures
>
>The three workers in the room saw a blue flash [Cherenkov radiation
>in eye fluid]. Reportedly they felt sick immediately. They left as
>quickly as they could. Apparently the team leader, who received a
>significantly lower dose than the other two, helped his team out of
>the room and then requested help. The distance to which these workers
>evacuated before waiting for medical treatment is unclear.
>
>The area's radiation (gamma) alarms activated, and everybody in the
>area left as quickly as they could. Most plant personnel were first
>evacuated to a far corner of site boundaries.
>
>News reports indicate some 7000 people were checked for radiological
>exposure. Significant exposures were apparently limited to the three
>workers in the room, 36 other plant workers, three firemen, and up to
>seven residents who were near site boundaries at the time. The three
>workers in the room respectively received estimated 17, 10, and 3Sv
>[Gy?] doses. [The first two workers were probably next to the tank, and
>the supervisor was probably a few feet away.] The next highest doses
>were to response and clean-up workers, each of whom reportedly received
>less than a 0.1Sv [Gy?] dose. [Apparently 5 firemen responded to site in
>an ambulance car, giving rise to a firemen/ambulance crew confusion.]
>
>News articles reported the three most severely exposed workers were not
>wearing dosimeter badges; their badges were apparently found some 150 or
>160 yards from the tank. [Were these badges actually removed during
>initial medical treatment at the plant, or did they fall off during the
>workers' evacuation, or were they truly not worn?]
>
>Firemen were exposed when they carried [wheeled? escorted?] the three
>severely exposed workers out of the plant and, apparently, accompanied
>these workers to the hospital. Firemen entered the area without
>appropriate personal protective equipment (PPE). Apparently they were
>not advised of conditions or accident type before entry. [Respirators
>and anti-contamination suits would help protect wearers from some
>fission products, splashed solution, etc. Also, news reports might
>include protective measures such as limiting time and using routes which
>are possibly better shielded than other routes. Nobody I talked with
>knows of PPE to protect from direct neutron radiation exposure (lead
>body suits?)]
>
>
>RADIOLOGICAL INFORMATION - monitor readings [possibly some or all Sv
>units should be read as Gy]
>
>About 10:37 on Sept. 30th, JAERI-NAKA personnel reportedly measured
>0.26 microSv/hr [gamma?,neutron?] about 2km southwest of the JCO plant.
>Some reports indicate JAERI personnel initially discounted neutron
>readings because their instruments occassionally give false information.
>
>On Sept. 30th between 11:36 and 11:50, 0.84mSv/hr gamma was measured
>across the street from the nearest site boundary. This gamma dose rate
>decreased slightly over time until about 00:00 on October 1st, when it
>began to drop more rapidly. By 06:30 levels were near normal.
>
>Neutron or nuetron-and-gamma sensitive instruments were eventually
>placed around the plant boundary. Dose rates of 4.5mSv/hr neutron and
>0.50mSv/hr gamma were measured at the nearest location between 19:09
>and 19:22 on Sept. 30th. (This is the earliest reported neutron dose
>rate measurement.) Measurements at approximate hourly intervals dropped
>steadily to 3.3mSv/hr neutron and 0.41mSv/hr gamma at about 23:30.
>Neutron readings then increased to 3.5mSv/hr about midnight, after
>which readings dropped. [I think this increase reflects a critical
>pulse, but it might be instrument noise.] By 06:30 neutron levels were
>below detection limits.
>
>You may view gif files about dose rates (in Japanese) at the following
>URLs. All times are Tokaimura local:
>- table of monitor readings; non-parentheticals are gamma and
> parentheticals are neutron in mSv/hr
> http://www.sta.go.jp/genan/jco/jco1-t.gif
>- chart of monitor readings; dashed lines are gamma and solid lines are
> neutron ("A" is location "4" from table of above graphic, "B" is
> location "6" from same table) [last critical pulse might have occurred
> soon after midnight, 0000 hrs Oct. 1st]
> http://www.sta.go.jp/genan/jco/jco2-t.gif
>- JCO site map showing monitor locations; apparently accident building is
> box with diagonal lines closest to monitor location 4, line of dashes
> separated by 2 dots is apparently site boundary, line of dashes
> separated by 1 dot is apparently monitoring boundary where different
> from site boundary and roads
> http://www.sta.go.jp/genan/jco/jco3-t.gif
> http://www.sta.go.jp/genan/jco/jco91007_5h.gif
> http://www.sta.go.jp/genan/jco/jco91007_5i.gif
>- table of monitor readings from Oct. 3rd, same locations as table above
> http://www.sta.go.jp/genan/jco/jco5-t.gif
>- table of monitor readings from Oct. 3rd-6th, same locations as tables
> above
> http://www.sta.go.jp/genan/jco/jco6-t.gif
>- possibly a table of survey readings in micro-Gy/hr from Oct. 3rd but
> monitor locations are not the same as in tables above
> http://www.sta.go.jp/genan/jco/jco4-t.gif
>- Aerial photo of survey point locations (Sewage plant, MP-1, and MP-2)
> at approximate distances of 0.7, 1.7 and 2 Km.
> http://www.sta.go.jp/genan/jco/jco91008a.gif
>- Plot of neutron dose rate data (very poor resolution)
> http://www.sta.go.jp/genan/jco/jco91008b.gif
>- Tables of environmental radiation monitoring data:
> Right two columns are neutron, middle two are gamma, at post 1 and 2.
> http://www.sta.go.jp/genan/jco/jco91008c.gif
> http://www.sta.go.jp/genan/jco/jco91008d.gif
>- Table of measurements at monitoring locations MP-1 and MP-2 and the
> sewage plant from above aerial photo. Column 1 is date/time, column
> 2 is wind direction, middle three are gamma (MP-1 & 2 and sewage
> treatment plant), and left three are neutron.
> http://www.sta.go.jp/genan/jco/jco91008e.gif
> http://www.sta.go.jp/genan/jco/jco91008f.gif
>- two more environmental monitoring report data tables, note on the
> leftmost column says the neutron dose measurements were made from
> inside an ambulance parked at these locations, units are
> microSievert for these specific tables.
> http://www.sta.go.jp/genan/jco/jco91008_E.html
> http://www.sta.go.jp/genan/jco/jco91008_F.html
>[Will somebody please translate what others have not already translated
>for me? Essentially that's anything not indicated in the descriptor
>before each URL]
>
>
>RADIOLOGICAL INFORMATION - fission products
>
>Fission products (noble gases [specifically xenon, krypton, and
>possibly iodine]) were released to the atmosphere, and their daughter
>products were measured outside the plant. [NOTE: A total release was
>most likely assumed for response actions. However, nomenclature and
>translation differences might also include neutrons and activated
>atmospheric nuclides, such as nitrogen, in whatever news reports were
>reporting as releases or contamination. Other releases, such as
>hypothetical droplets from the tank, most likely did not make it out
>of the building unless workers and responders carried it out on
>their PPE.]
>
>News reports indicate I-131, I-132, and I-133 were released into the
>environment until Oct. 12th, when an exhaust fan was finally shutdown
>and building windows and outlets were sealed. Although releases are
>too low to be a health hazard, the I-131 release was 0.000021 bq/cm3
>compared to a normal or legal level of 0.00001 maximum. The other
>two isotope levels were well within standards. Apparently no iodine
>monitors were brought in until Oct. 7th, but reasons for monitoring
>and response delays were not reported. (FYI: Monitoring between
>Oct. 7th and 9th detected 0.00000044 bq I-131 about 70km southwest
>of the plant.)
>
>Dr. Per F. Peterson and Dr. Joonhong Ahn from the University of
>California at Berkeley completed PRELIMINARY power, fission product
>generation, and fission product release calculations on October 2nd.
>These calculations were neccessarily based on information from early
>news reports. Their results overpredict generation and releases
>because they assumed 22 hours of operation at about 5 to 30kW after
>initial boiling ceased. Their preliminary results include 30 to
>180Cu total Xe-133 released and 10 to 60 Cu (1 to 7 Tbq) total
>I-131 released. Further, their preliminary estimates of gaseous
>fission product yields are:
> nuclide half-life yield (atoms/atom U-235 fissioned)
> Kr-25 10.76 yr 0.013
> I-131 8.05 dy 0.0293
> Xe-133 5.27 dy 0.0661
> I-135 6.7 hr 0.0609
>
>
>RADIOLOGICAL INFORMATION - contamination
>
>Fresh fuel materials at the site were neither contaminated nor
>irradiated.
>
>[I do not know if solution or droplets splashed out of the tank.
>I also do not know if any radiological contamination was tracked
>about as workers evacuated and responders moved in the general area.
>Non-technical information and less-than-precise translations often
>lump radiation and contamination together. Reports of contaminated
>items might actually refer to irradiated items and/or activated
>nuclides.]
>
>
>EMERGENCY RESPONSE OUTSIDE PLANT - Notifications
>
>It now seems responders were notified and activated separately from
>authority notifications. Notifications to offsite responders might
>have warned offsite authorities.
>
>Plant personnel completed initial notifications to JCO officials
>within ten minutes. Some notification information was not clear
>because at least one company official did not understand they
>were dealing with a criticality accident. Apparently none of these
>officials instructed plant personnel to notify and/or establish
>communications with city or regulatory authorities.
>
>Apparently the first notification to [unidentified] outside officials
>was made at 11:15, but city authorities indicated they were not notified
>until around 11:30. Apparently the IAEA was not notified officially.
>
>Residents were notified up to 2.5 hours after the first pulse, although
>there are indications that the first announcement was made before noon.
>
>
>EMERGENCY RESPONSE OUTSIDE PLANT - Responders
>
>Initial radiological responders were apparently from plant personnel
>but, as response continued, they were supplemented by personnel from
>nearby nuclear plants. Other in-field responders were from the civil
>
>firefighters (rescue), ambulance crews, civil police (civil evacuation,
>patrol evacuated areas, traffic control), and army.
>
>Defense Agency (army) dispatched many people and other resources:
>-- 64 self-defense officials, 3 medical officers, another 18 officials,
>3 chemical protection vehicles, 8 chemical decontamination vehicles, 15
>ambulances, 11 large buses, and 13 microbuses from 3 or 4 different units
>to Katsuta Garrison.
>-- 26 officials and 7 decontamination vehicles to various medical and
>civil centers in Mito and Omiya.
>[Some chemical PPE is like radiological PPE.]
>
>JAERI and JNC supplied monitoring, sampling, analysis, and sent data to
>all involved authorities.
>
>JAERI supplied personnel, neutron-shielding materials, radiological
>protection equipment, monitoring car, radiation measuring instruments,
>3 evacuation buses, etc.
>
>JNC supplied personnel, 3 monitoring cars, 2 evacuation buses, a fire
>engine, radiation measuring instruments, etc.
>
>Environmental Agency supplied advisors, off-site environmental monitoring,
>etc.
>
>ETC, ETC. [contact me if you desire more data]
>
>
>EMERGENCY RESPONSE OUTSIDE PLANT - Centers
>
>City officials activated some center or communications network. News
>reports indicated these officials were left to determine response
>actions for residents on their own.
>
>STA established the Local Countermeasure Headquarters headed by the
>State Secretary for Science and Technology in Tokai JAERI, dispatching
>personnel to the headquarters. STA collected information and assisted
>JCO response with the cooperation of, and materials and equipment from,
>JAERI, the Japan Nuclear Cycle Development Institute (JNC) and electric
>utility companies. The Nuclear Safety Commission (NSC) convened the
>Emergency Technical Advisory Body and dispatched a group of experts
>including NSC members. Ministry and agency staff members assembled at
>the On-the-spot Headquarters. Responders acted under the guidance of
>experts from the Local Headquarters and with support provided by
>related organizations.
>
>Government Accident Countermeasure Headquarters consisting of the
>Minister for Science and Technology as chief and representatives from
>the ministries and agencies involved, met to discuss and decide such
>actions as sheltering. The Government Task force for the Accident
>headed by the Prime Minister was established to discuss and decide on
>measures to be taken by the Government. [How does this fit with city
>official statements of advice they received (above)?]
>
>News reports indicate communications between responders in different
>locations was almost exclusively by telephone and, later, fax, with
>exception of firefighter, police, and army personnel who had radios
>and similar equipment.
>
>
>EMERGENCY RESPONSE OUTSIDE PLANT - Protective Measures
>
>About 160 people within a 350m (380yard) radius were evacuated from
>15:00 September 30th until 18:30 October 2nd [about 4.5 hours after
>the first pulse of a cycling accident? Some residents say they were
>advised to evacuate about 12:30 but no such indication is included
>in official records. NOTE: Those who calculate evacuation boundaries
>tell me the 12rad dose boundary is about 300yd if one assumes a point
>source, 2E19 fissions, and no shielding, and if one accounts for
>activated atmospheric nitrogen.] Evacuees gathered at a shop about
>700m from the plant, and were then bused to a village center about
>1300m away. However, after a night in temporary shelters, some
>evacuated residents reportedly returned home early to care for pets
>and/or retrieve fresh clothing.
>
>All roads within 1km of the plant were closed except to emergency
>vehicles, apparently until the evacuation order was lifted.
>
>Authorities advised people within 10km (6miles) to shelter (stay inside
>with doors and windows closed) from about 22:00 September 30th to
>15:00 October 1st. This was a precautionary measure, because the
>accident system was not considered stable, although dose rates were
>well within guidelines. The radius includes all of Tokai Village
>(Tokaimura) districts; parts of Mito, Hitachi, Hitachi-Ohta, and
>Hitach-Naka cities; and parts of Naka, Urigura, Ohmiya, and Kanasogoh
>towns. The affected resident population is about 310,000. During that
>time all 135 schools and 50 post offices within the radius were closed,
>Hitachi and many businesses in the region were closed, Japan railways
>suspended train service between Mito and Hitachi, Ibaraki Traffics
>(the dominant bus company in the region) suspended all services, and
>Japan Highway Services closed the Mito/Hitachiminami-Ohta section of
>the Joban Highway (connects Tokyo and Tokai regions).
>
>Authorities also warned people they should not eat produce or drink
>milk from the area until testing was complete. That ban was lifted by
>October 4th, and, to bolster confidence, Prime Minister Obuchi turned
>a meal in Tokaimura (of local produce) into a news story. Harvest
>shipments were suspended for three days per government order, while
>fishery cooperatives and food processers voluntarily suspended
>operations at the same time. Wholesale prices for vegetables grown in
>Ibaraki Prefecture, fell by more than half pre-accident prices. All
>such operations are out product and money due to shipping delays and,
>possibly, food spoilage.
>
>
>MEDICAL TREATMENT
>
>Only the three most severely exposed workers exhibited radiation
>sickness symptoms, contrary to non-Japanese news articles seemed to
>indicate others were also sick.
>
>News reports said all three workers were still alive as of Oct. 11th.
>There were no further reports to date [18:30 MDT, October 13th]
>
>At first they exhibited all(?) classic early symptoms, including Na-24
>in their vomit. They were first transported to a hospital in Mito,
>and then taken by helicopter to be treated by radiation experts at
>the National Institute for Radiological Science in Chiba Prefecture.
>(One or more of these experts assisted Russian doctors in treating
>victims of the Chernobyl accident.)
>
>These patients were placed in sterile rooms, their individual symptoms
>are treated as needed, and all precautions are taken to avoid
>infections. Immediate treatment included "uranium antidote" injections,
>prescription steroids, and measures to prevent or minimize dehydration.
>Doctors say it is most encouraging that all three patients have
>survived so long after their exposure.
>
>Fifty-four year old Yutaka Yokokawa received an estimated 3Sv (300rem).
>Unlike the other two workers, he did not lose consciousness and walked
>into the hospital. Apparently he could answer a few questions
>immediately after the first accident pulse, but he was not fully
>coherent. He recovered sufficiently to answer police questions October
>2nd. His blood pressure and body temperature were normal by late Oct.
>6th. However, full radiation sickness effects could still set in. He
>is still expected to recover fully without a bone marrow or blood cell
>transplant, if he can avoid any serious infections.
>
>Medical personnel indicate the other two workers received lethal
>radiation doses. However, medical advances and a lot of luck might save
>them. Doctors started blood-cell-transplant preparations soon after
>these men were admitted to the Research Hospital of the Institute of
>Medical Sciences at the University of Tokyo. Apparently their prognosis
>is hopeful if they survive these transplants by one month.
>
>Thirty-five-year-old Hisashi Ouchi received an estimated 17Sv (1700rem).
>One of Ouchi's siblings is a near-perfect match. This sibling agreed to
>be a donor and doctors gave the sibling medicines to stimulate cell
>production. Doctors performed the first peripheral blood stem cell
>transplant on October 6th, although news articles reported Ouchi showed
>signs of pneumonia just hours before the procedure. He received a
>second transplant before Oct. 11th. (Stem cells are immature blood
>cells that can develop into either red or white blood cells, or
>platelets. This technique is about 10 years old, but this is its first
>use on radiation victims. It's advantages include no need to obtain
>bone marrow, requires less cell volume, and can be repeated at
>three-day intervals for a while.)
>
>Thirty-nine year old Masato Shinohara received an estimated 10Sv
>(1000rem). By late October 2nd, he was conscious and lucid, with a
>112/70mmHg blood pressure, 20500/mm3 leucocyte level, 1% lympha node
>(the absolute value : 205/mm3), and 36.9C body temperature. Since none
>on Shinohara's relatives is a close enough match, doctors decided an
>umbilical cord blood cell transplant is the most appropriate
>procedure. He received the [first?] transplant Saturday, October 9th.
>
>
>INVESTIGATION
>
>Accident investigation for response purposes began immediately.
>Whether or not responders had applicable procedures, their
>information-gathering methods apparently are similar to methods
>typically specified by procedures in the USA.
>
>Further investigation apparently began in earnest the afternoon of
>October 1st.
>-- JCO conducted an in-house investigation.
>-- Police began conducting an extensive criminal investigation
>(suspicion of JCO negligence and violating nuclear safety laws).
>Their investigation included several raids on JCO offices.
>-- On-the-spot inspection based on the Law on the Regulation of Nuclear
>Source Material, Nuclear Fuel Material and Reactors began October 3.
>-- On October 4, Government Task force for the Accident in the
>Tokaimura Uranium Processing Facility decided the measures to be taken
>by the Government.
>-- NSC and STA will combine technologial abilities of experts to
>investigate the accident and "to take every possible measure to prevent
>similar accidents from occurring."
>-- On October 7, NSC established the Accident Investigation Committee.
>-- At invitation of Japanese authorities, On Oct. 12th the IAEA
>dispatched a three person team to conduct, or participate in, an
>investigation. Japanese officials hope this move will help restore
>public confidence in the Japanese nuclear industry. Japanese nuclear
>authorities also plan to report on the accident during IAEA and
>OECD meetings in Europe.
>
>
>MISCELLANEOUS CONSEQUENCES, RESPONSE, and REACTIONS
>
>Tokaimura resident attitudes range from calm to angry over nuclear
>safety issues. However, most do not seem to be worried about
>long-term health effects from this accident. [Non-Japanese people
>seem more worried about Japanese resident exposures, and this
>accident in general, than these residents.]
>
>JCO established counseling services for area residents and farmers.
>
>JCO and its parent company, Sumitomo Metal Mining Co., promised to
>pay compensation. JCO will also probably be fined.
>
>The regulator apparently revoked JCO's operating license for this
>plant, effective Nov. 1st. This effective date allows JCO to remove
>licensed materials. Speculation is that the plant will not reopen
>unless another company buys it, revamps its safety basis, and
>re-licenses it. Reports that the regulator revoked or suspended other
>JCO licenses are unconfirmed, and possibly premature if not false.
>
>Stock in Sumitomo Metal Mining Co. dropped. Banks were reconsidering
>its and/or JCO's credit rating. Sumitomo later announced neither they
>nor their subsidaries would continue in nuclear operations.
>
>Two Greenpeace activists measured radiation and/or contamination
>levels around the JCO facility and Tokaimura. Greenpeace charges
>that hundreds, rather than about 50, were overexposed in the accident.
>[consider the source?]
>
>Oversight (Science and Technology Agency and Nuclear Safety
>Committee) inspection effectiveness is questioned.
>
>The regulator ordered inspections for all 51 [power?] reactors.
>Regulator and/or operator inspections are also being conducted at
>some 163 non-reactor sites which use licensed materials. Further,
>the regulator planned to search offices of 20 nuclear-related
>facilities.
>
>The regulator plans to perform a critical experiment mockup in
>JAERI's TRACY critical facility
>
>Apparently applications to fully reopen the uranium reprocessing
>plant in Tokaimura are delayed due to the subject criticality
>accident. The reprocessing plant is at least partially shut down
>right now due to a fire and explosion in 1997.
>
>Prime Minister Keizo Obuchi delayed reorganizing the Japanese cabinet.
>
>The Japanese government probably will not revise its nuclear policy,
>despite an apparant drop in public confidence. However, legislators
>plan to write a nuclear emergency law and to revise an existing
>nuclear safety law. Polls indiacte that, at least for now, public
>confidence in the policy and nuclear energy has dropped. However,
>this drop is attributable to several recent adverse nuclear incidents.
>
>An ex-JCO chairman/president, who left JCO in June 1999, resigned
>from a prestigious government position.
>
>JOYO and the Fugen advanced thermal reactor might run out of fuel
>before more can be manufactured in Japan. Speculation indicates
>other companies might be further discouraged from commercializing
>MOX fuel for LWRs. Japan Nuclear Fuel Co. (JNF), a Japanese-U.S.
>nuclear fuel manufacturing joint venture, will import all its UO2
>(up to now JNF purchased about half of its UO2 from JCO and the
>rest from a JNF-General Electric joint venture). However, there is
>apparently no need to import [finished?] LWR fuel.
>
>Other Japanese nuclear-related organizations and electrical power
>organizations are providing maximum assistance to Tokaimura
>residents and officials, Ibaraki Prefecture government, and JCO.
>
>If USA experience is indicitive, the JCO plant's entire safety basis
>will be scrutinized and reanalyzed. [Revision depends on if anybody
>plans to relicense the plant.]
>
>Personnel in USA, UK, and several other countries are reviewing
>criticality safety programs and safety bases at all non-reactor and,
>possibly, reactor nuclear facilities in light of the accident. Many
>reviews began before regulatory authorities ordered them. Reports to
>news and regulatory staff in most countries with nuclear operations
>indicate, "it can't happen here for a variety of reasons."
>
>Some, not necessarily all anti-nukes, are questioning nuclear
>inspection programs and nuclear safety culture throughout the world,
>in all its aspects. The IAEA admits it has concentrated on power
>plants since the Chernobyl accident.
>
>The French IPSN apparently reported this was the first criticality
>accident with less than 20% enriched fuel. [If IPSN did say that,
>this spokesperson is unaware of, or is ignoring, the Electrostal
>Fuel Fabrication Plant (USSR) on 13 November 1965 with 6.5% enriched
>uranium, and, since there is little difference between 18.8 and 22.6%
>enriched material, the Siberian Chemical Compound (USSR) accident on
>14 August 1961. (Russians reported these accidents at the ICNC'95
>meeting in Albequerque, New Mexico.) At least some IPSN personnel
>are aware of the paper since Russian accidents were included in the
>totals IPSN officials gave French journalists soon after the
>Japanese accident. (By the way, Los Alamos people announced an
>update to an overall criticality accident review report, which will
>include Russian accidents, at the ICNC'99 meeting in Versailles
>just a few weeks ago.)]
>
>US DOE will send a three-man team to Japan to learn more from Japanese
>authorities. The team includes leader Mr. Frank McCoy, deputy manager
>of the DOE's Savannah River Operations Office, process and analytical
>chemist Dr. Leroy C. Lewis, and well-known LANL criticality safety
>group leader Dr. Thomas P. McLaughlin.
>
>US President Clinton threatened to (or did) veto a bill regarding
>Yucca Mountain and nuclear waste.
>
>
>Coverage in German at http://homepages.go.com/~ripeill/tokaimu1.htm
>
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