|Nyt om atomkraftulykken i Japan
den 30. september 99.
E-mail afsendt fra Japan 5. november
Thu Nov 4 18:20:49 1999
Date: Fri, 5 Nov 1999 01:26:31 (lokal tid) +0900
From: email@example.com (Hosokawk)
Subject: MagpieNews #991104 (Tokai accident-23rd report)
Magpie Country Nukes Headliner
nuclear issues news brief from Japan
Criticality accident at Tokai uranium processing plant
STA ADMITS GENERAL PUBLIC EXPOSURE TO NEUTRON RADIATION;
DOSE ESTIMATION PUBLICIZED;
REGISTRATION OF THE EXPOSED RESIDENTS FOR LONG-TERM HEALTH
4 November 1999
The Tokai Criticality Accident Investigation Committee today presented the results of the
analysis of the uranium solution samples obtained from the accident site (see 22nd report).
According to the calculation by the Japan Atomic Energy Research Institute (JAERI), the first
25 minute of the criticality, which eventually lasted nearly 18 hours, yielded a total 75mSv
exposure at the distance of 80m from the ground zero. (This is the minimam distance from
the precipipitation tank where the uranium went critical to the JCO site boundary).
It is estimated that as much as 48% of the total energy emmission took place during the first
25 minutes of the criticality.
The cumulative doses for the first 5 hours (i.e. before the residents evacuated) are estimated
by STA at 110mSv at 80m point, and 1.4mSv at 350m point (neutron plus gamma, roughly at
10:1 proportion). This can mean that almost all the members of the general public around the
plant had got the dose over annual limit (1mSv) before they escaped.
STA (the Science and Technology Agency of the Japanese Government) says that the doses
are of harmful levels in a long term, and admits that there is a high possibility that the
members of the general public around the site were exposed to considerable doses.
Oh, what a decent expression!
Also publicized today are the doses suffered by the JCO workers (other than those of the rush
platoon) on site on the day of the accident: between 64mSv (max) and 0.6mSv (min). As
reported earlier, the rush platoon members were dosed with the maximum of 120mSv.
The seven construction workers, who had been working outdoors on a ground adjacent to the
JCO plant (not "golf course" as incorrectly reported earlier), were dosed with between 15mSv
(max) and 6.4mSv (min).
From the data newly disclosed by JAERI/STA, Dr Jinzaburo Takagi estimates the number of
the fission at around 2.5E+18, and the weight of U235 that went into chain reaction at around
1mg. He reserves a possibility that the figures may be larger if we consider the problems in
the method of taking samples (see 22nd report).
Earlier on 29th of October, the local governments (namely Tokai-mura and Naka-machi, with
the supervison of Ibaraki Prefecture) started to register the affected people. Initially 120
evacuees were registered, and a hundred more people are expected to register, not only the
residents, but also the passers-by who happened to be in the neutron radiated areas on the day
of the accident. The prefecture administration say that those registered will be monito red
over 10 years period for their health conditions.
The residents of the radiated zone are expressing fear and anxiety over the state of affairs.
Media reports also oscilate between "no worries" and "cancer in ten years". Discriminations
not only against the farm and sea products of Tokai region, but also against the people are
already being reported, as it happened very badly against the surviving victims of Hiroshima
One big question is what lessons we ever had in the last 54 years of nuclear age...
OOA, Blegdamsvej 4 B - st, 2200 Kbh. N.
Tlf: 35 35 55 07, Fax: 35 35 65 45
Sidst opdateret 8. november 1999