ML20205N604
| ML20205N604 | |
| Person / Time | |
|---|---|
| Issue date: | 05/08/1986 |
| From: | Speis T NRC |
| To: | Rich Smith STATE, DEPT. OF |
| Shared Package | |
| ML20205N459 | List: |
| References | |
| FOIA-86-335 NUDOCS 8704030064 | |
| Download: ML20205N604 (5) | |
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- 8 NUCLEAR REGULATORY COMMISSION I
- 7. WASHINGTON. D. C. 20005 MEMDRANDUM FOR: Richard Smith
.Chernobyl Working Group Department of State FROM: Dr. Themis P. Speis, Director Chernobyl Incident Tracking Team
SUBJECT:
ATTACHED OFFER OF U. S. AID Attached is a proposed offer to the USSR of U. S. aide in assessing the potential for contamination of ground water at Chernobyl and possible measures for mitigating such effects. We suggest that this offer be made through the appropriate diplomatic channels.
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U. S. Aid in Assessing the Potential for Contamination'of Ground Water at Chernobyl and Possible Measures for Mitigating Such Effects 1
Following core melt and the airborne release of fission products, the molten I core debris can be expected to accumulate on the concrete floor.(basemat) of the reactor enclosure. The combination of thermal and chemical attack by the core debris may result in penetrating the concrete floor and entering the underlying soil and rock. This could result in contamination of ground water and eventually in the transport of radioactive material to surface water (rivers and reservoirs). The USNRC has considerable expertise and, analytical techniques to assist the Soviets in dealing with this aspect of the accident.
. l With regard to the possibility of basemat penetration, the U.S. has a great i deal of relevant experimental data, and a large store of existing calculations I and expertise. We also have access to detailed computer codes. The rate and extent of basemat penetration depends on the degree of confinement of the core debris, the accident sequence causing the core melt-down, the core design, the amount of dissolved structural materials in the core debris, the presence or absence of water and the composition and thickness of the concrete. The USNRC could assist the Soviets to assess the current status of l
core-concrete interactions and to evaluate options for inproving the situation. ,
If the concrete basemat is penetrated, the USNRC can assist the Soviets in j estimating the potential for contamination of ground-water and surface water.
! Because the processes which lead to water contamination are typically quite slow, we can also assist in evaluating engineering measures to limit the extent
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' to core melt accidents. We have also evaluated potential engineering measures to prevent the spread of water contamination. In addition, we have analytical methods for estimating the transport of radioactive contaminants, Our expertise, experience and calculative methods, relating to both basemat 1
penetration and ground water contamination, can be made available to the I i Soviets in a number of ways. First we could make available the results of existing studies, either in the form of reports or in sumarized form. We are also available to answer specific questions or to consult with the Soviets on an interactive basis. Moreover, we can use our analytical methods to perform site-specific analyses for Chernobyl. Site-specific analyses would require I
that we have access to plant design information, site geologic and hydrologic h
data, and some details about the event including actions taken after the accident initiation.
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up*f' NUREG-1054, " Simplified Analysis for Liquid Pathway Studies".
NUREG/CR-4251, Volume 1, " Mitigative Techniques for-Ground-Water Contamination Associated with Severe Nuclear Accidents, Analysis of Generic Site Conditions".
NUREG/CR-4251, Volume 2. " Mitigative Techniques for Ground-Water Contamination Associated with Severe Nuclear Accidents, Case Study Analysis of Hydrologic Characterization and Mitigative Schemes."
NUREG/CR-1596, "The Consequences from Liquid Pathways After a Reactor Meltdown Accident." SAND 80-1669, NUREG-0440, " Liquid Pathway Generic Study: Impacts on Accidental Radiation Release to Hydrosphere" NUREG-0850, Volume 1, " Preliminary Assessment Core Melt Accidents, Zion and Indian Point Nuclear Power Plants and Strategies for Mitigating Their Effects".
NUREG-0054, Supplement No. 3 to NUREG-75/100, " Safety Evaluation Report related to Offshore Power Systems Floating Nuclear Plants (1-8)."
Article, Health Physics, Volume 49, No. 5, " Potential Contamination of Surface Water Supplies by Atmospheric Releases from Nuclear Plants."
Article, Nuclear Safety, Vol. 27, " Plant Safety Features - Technical Note: Existing Reactors Can Be Made 'Ultrasafe'".
Testimony, Richard Codell, "In the Matter of Indian Point Unit 2 and Unit 3, Concerning Consnission Question 1".
U.S. Contribution to CSNI PWG2 Task Grcup on Ex-Vessel Severe Accident Thermal-Hydraulics.
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OF ENVIRONMENTAL RESULTS FROM NRC LICENSEES MAY 9,1986 LICENSEE DATE MEDIA RESULT UNITS Davis Besse 5/7/86 Precipitation I-131 2.5 pCi/l pCi/ pat 3 Penn State 5/7/86 Air I-131 3.4E-3 Cs-137 9.5E-4 "
Ru-103 trace <1E-3 "
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