ML19247D088
| ML19247D088 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah, McGuire  |
| Issue date: | 02/10/1981 |
| From: | Murley T NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19247D089 | List: |
| References | |
| NUDOCS 8102280325 | |
| Download: ML19247D088 (2) | |
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h [.2.,8/g 6 b.r MEMORANDUM FOR:
D. Eisenhut, Director
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Division of Licensing A
Office of Nuclear Reactor Regulaticn 5
FROM:
Thomas E. Murley, Director
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Division of Safety Technology Office of Nuclear Reactor Regulation
SUBJECT:
SU5MITTAL CF ROUGH CPAFT-SANDIA RE?CRT" ANALYSIS OF HYDROGEN MITISATION FOR DEGFADED CORE ACCIDENTS IN THE SEQUOYAH NUCLEAR PCWER PLANT (DECESSER 1, 1950)
FOR ASLB NOTIFICATICN CCNSIDEFATICN Discussion The interim distributed ignition system (IDIS) proposed by TVA and found acceptable by the staff for operation is the interim solution to the issue of hydrogen control for degraded core accidents. TVA in the design and installation of the IDIS has located 4 glow plug ig.1iters in the upper plenum of the ice condenser section of the containment.
Sandia National Laboratory in tne rough draft report entitled, " Analysis of Hydrogen Mitigation for Degraded Core Accidents in the Sec;uoyah Nuclear Power Plant," December 1,1980, has recommended that the igniters located in the upper plenum be removed. Their basis for the recommendation is that there may be accident scenarios where the lower compartment atmosphere is steam inerted or oxygen deficient. Thus, the ficw through the ice bed may exit with highly enriched hydrogen concentraticns, concentrations high enough to be detonable (Sandia considers 18t as the lower limit of detonability). Sandia is concerned about the effects of detonations in the upper plenum region.
The staff previously considered this issue of igniter 1ccation and concladed that 1) typical small break analysis has not shown the lower compartment to be steam inerted or oxygen deficient; 2) TVA has considered the effects of detcnations in the upper plenum and ccncluded that the effects are minimal and would not result in breach of containment; and 3) locating igniters in the upper plenum is beneficial for reducing the hydrogen accLaulation in the upper compartment.
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However, as a result of my review of the draf t Sandia report, I have recorrended to DSI (See enclosure) that the staff position on the igniters in the upper plenum of ice condenser plants be evaluated in acre detati in the coming months.
Since this rough draft document recorrends an action suggesting the staff position on the upper plenum igniters may be unconservative, we recomend it be considered for submittal to any ASL Boards presently hearing operating license prcceedings or those hearing operating license amendments considering Hydrogen Control and Mitigation. This is in conformance with NRR Office Letter 19, Revision 1-Precedures for Notification to Licensing Boards of Relevant and Material New Informa tion.
Thocas E. Murley, Director Division of Safety Technology Office of Nuclear Reactor Regulation
Enclosure:
Me::orandum T. Murley to D. Ross dtd Feb. 9,1981 Distribution Copies:
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