ML19323B538
| ML19323B538 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/04/1980 |
| From: | Budnitz R NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Dircks W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| Shared Package | |
| ML19323B539 | List: |
| References | |
| NUDOCS 8005130498 | |
| Download: ML19323B538 (2) | |
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UNITED STATES
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tiEliORANDUM FOR: William J. Dircks Acting Executive Director for Operations FR0!1:
Robert J. Budnitz, Director Office of Nuclear Regulatory Research
SUBJECT:
IllPLEliENTATION OF RECOMi1ENDATIONS OF SPECIAL TASK FORCE ON THREE f1ILE ISLAND CLEANUP
Reference:
Your memorandum of flarch 6,1980, same subject Enclosed is the report "A Further Evaluation of the Risk of Recriticality At Tf4I-2," which you requested be prepared in the referenced memorandum.
This report reviews previous studies related to the probability and consequences of criticality at the damaged Three Mile Island Unit-2 reactor. More detailed assessments are performed to confirm the adequacy of those studies and to provide additional insight into ways to rainimize risk from criticality.
The most important con-clusions of this study are:
1.
The most probable mechanism for criticality, boron dilution, is a slow enough process that with appropriate instrumentation and procedures, the approach to criticality can be detected and corrected.
To the extent that boron concentration in excess of 3500 ppm can be ensured, the probability of criticality is further minimized.
2.
The most likely direct radiological consequence of criticality is increased dose rates inside containment.
For the more realistic and more probable criticality events studied, off-site consequences are nonexistent. More conservative assumptions regarding the nature of the criticality, combined with multiple failures of engineered safety features are required before one calculates detectable health effects.
Even then, the consequences, as expressed in terms of the probability of latent cancer fatality, appear to be very small compared to the observed incidence of cancer death. To the extent that core cooling and containment integrity can be maintained, the consequences of criticality can be further minimized.
4 William J. Dircks '
This completes RES' response to Task V of the referee.ced memorandum.
Robert J. Budnitz, Director Office of Nuclear Regulatory Research
Enclosure:
Report As Stated cc w/ encl:
H. Denton, NRR V. Stello, IE H. Shapar, ELD J. Fouchard, PA R. Minogue, SD J. G. Davis, NMSS B. Snyder, TMI-2 Public Document Room,M 4
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