|Nyt om atomkraftulykken i Japan
den 30. september 99.
E-mail afsendt fra Japan 15. oktober
Fri Oct 15 12:46:51 1999
Date: Fri, 15 Oct 1999 18:19:51 (lokal tid) +0900
From: email@example.com (Hosokawk)
Subject: MagpieNews #991015 (Tokai accident-19th report)
Magpie Country Nukes Headliner
nuclear issues news brief from Japan
Criticality accident at Tokai uranium processing plant
PROMPT CRITICALITY OCCURRED, NSC ANALYSTS CONFIRM; IAEA
INVESTIGATION UNDER WAY; RADIOACTIVE IODINE KEPT RELEASED OVER 10
DAYS; STA NEGLECTED SITE INSPECTION FOR YEARS; MONITORING OF
RESIDENTS HEALTH REQUESTED
15 October 1999
It has now become clear, according to the analysis by the accident investigation unit of the
Nuclear Safety Commission, that the Tokai criticality accident started with what the nuclear
physicists call "prompt criticality", rather than the reactor-type delayed criticality. This means
the accident could have been much worse and totally out of control.
JCO admitted that a limited amount (20Bq/m^e, i.e. twice the allowed limit!) of radioactive
iodine-133 had been kept going out into atmosphere after the accident via exhaust system of
the building in which the criticality occurred. The exhaust system switch was on until
October 11. More than 10 days after the accident, JCO hastily sealed up the windows of the
building in question in order to avoid further release. (More workers exposed during the
Apparently, Prefecture and STA knew about the iodine release thruough the exhaust system,
but they took no measure considering that the escaping quantity was negligible.
Concentration of 0.04Bq/m3 of I-131 was detected 50m southwest of the building (the
monitoring point is still within the JCO premises).
Almost all the mass media stopped reporting about the conditions of the hospitalized workers
suffering acute radiation injuries. US marrow transplant expert, Dr Robert Gale, who also
treated Chernobyl liquidators, arrived at Tokyo to attend the victims. We have very little
information about the kind of treatment that is being tried on.
Executives of the JCO Sumitomo now confessed that their employers had been taught almost
nothing about nuclear criticality, why and how they should avoid it.
IAEA experts team arrived at Japan in order to investigate into the accident. The three
members of the team are interviewing administrators of STA, Ibaraki Prefecture and Tokai
Village (Tokai-mura). They will also visit the site of the accident.
On the 3rd of October, after the accident, STA sent a site inspection team to the JCO plant.
This is the very first time in 10 years that a site inspection, which is legally prescribed, on this
plant is carried out. Unlike powerplants with nuclear reactors, periodic inspection is not
obligatory in fuel processing facilities in Japan.
It was also revealed that STA had conducted no site inspection either at Tokai Reprocessing
Plant (operated by JNC) or at Rokkasho-mura Enrichment Plant (operated by JNFL) over six
years. STA claims they were too busy.
... Too busy with safety PR activities?
Toshiba, Hitach and US General Electric are jointly preparing for a new nuclear fuel plant in
Japan, and JCO had been expected to supply 50% of UO2 material for this new facility. Now
that JCO is definitly out of business, Toshiba/Hitach/GE has decided to import all the
material uranium from overseas. [Nikkei, 14 Oct 99]
UK journal Nature No.401 carried an editorial opinion harshly criticising the sloppy,
rubber-stamping practices of the Japanese nuclear safety regulation, and casting a serious
doubt whether the situation improve significantly after the accident.
Greenpeace Japan requested in writing that STA should conduct follow-up surveys on the
health of the near-by residents. Evacuation of 350m radius of the ground zero was no doubt
insufficient. And the evacuation started only after 4 or 5 hours after the criticality sparked.
This means that all the people who were in the area, perhaps as far as 500 to 600m radius
zone, were subject to a quite dangerous level of neutron shower. Latent radiation injury is
likely to occur.
OOA, Blegdamsvej 4 B - st, 2200 Kbh. N.
Tlf: 35 35 55 07, Fax: 35 35 65 45
Sidst opdateret 19. oktober 1999