Properties and genesis of hot particles from the Chernobyl reactor accident

Conference · Tue Dec 30 23:00:00 EST 1997

OSTI ID:572293

Schubert-Bischoff, P ^[1]; Lutze, W ^[2]; Burakov, B E ^[3]

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1. Hahn-Meitner-Inst. Berlin (Germany)
2. Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering
3. Khlopin Radium Inst., St. Petersburg (Russian Federation)

On April 25, 1986, the nuclear reactor Unit 4 (RBMK) at Chernobyl, Ukraine, exploded. Besides molecular species, the fallout contained particles of relatively high specific activity (hot particles) with a wide range of chemical compositions. The composition of a hot particle bears information about its genesis. Particle sizes ranged from a few to 100s of Micrometers. Data on a hot particle, found in Berlin, Germany, is presented and discussed in context with earlier measurements on other particles to understand their genesis. The chemical composition was determined by electron probe micro analysis. Particles are either reactor fuel (one) or fission product alloys (nine). The alloys were formed during normal reactor operation. Strongly varying concentrations of Fe and Ni suggest that at least some of the particles reacted with molten structural material of the reactor. The particles were mobilized by fuel oxidation or fuel dust generation during the accident. The fission product composition can only be examined if the authors assume that the alloys remained in the solid state in the course of the accident. Some particles may have been ejected during the explosion, others later while the reactor was burning. Activities ({sup 103}Ru and {sup 106}Ru, originally up to 160,000 Bq) of ten year old particles were re-measured but were no longer detectable. No long-lived {gamma}-emitters were found. The {sup 99}Tc activity was calculated and found to only 1Bq. The {gamma}-spectrum of the fuel particle still shows {sup 137}Cs (1 Bq) and {sup 60}Co (<1 Bq).

• OSTI ID: 572293
• Report Number(s): CONF-961202--
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
22 GENERAL STUDIES OF NUCLEAR REACTORS
54 ENVIRONMENTAL SCIENCES
ACTIVITY LEVELS
CESIUM 137
CHEMICAL COMPOSITION
CHERNOBYLSK-4 REACTOR
COBALT 60
FEDERAL REPUBLIC OF GERMANY
FISSION PRODUCT RELEASE
ORIGIN
PARTICLE SIZE
RADIOACTIVE AEROSOLS
RUTHENIUM 103
RUTHENIUM 106
TECHNETIUM 99