ML19224A865
| ML19224A865 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/17/1979 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Anderson T WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| NUDOCS 7906070056 | |
| Download: ML19224A865 (3) | |
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UNITED STATES 8,
NUCLEAR REGULATORY COMMISSION
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MAY 171979 Mr. Tom M. Anderson, Manager Nuclear Safety Department Westinghouse Electric Corporation P. O. Box 355 Pittsburgh, Pennsylvania 15230
Dear Mr. Andersen:
SUBJECT:
ACRS RECOMMENDATIONS RELATING TO THI-2 ACCIDENT As you krod, the Advisory Comittee on Reactor Safeguards (ACRS) has written three separate letters to the Comission relating to the TMI-2 accident. These letters were issued on April 7, April 1E,, and April 20, 1979. Each of these letters contains specific recomendations which must be addressed.
The ACRS has discussed these recommendations with the staff and industry at recent ACRS subcomittee and full comittee meetings. We anticipate that this dialogue will continue in the forth-coming ACRS subcomittee meeting on THI-2 (May 31-June 1).
For this reason, we are requesting that all light water reactor vendors provide the staff with a concise discussien and position on each of the ACRS recommendations relating to TMI-2.
For your convenience, we have provided in the enclosure a list which contains each ACRS recomendation of which we are aware. We request that you provide your response to each of these ACRS recomendations to be received by the staff no later than May 23, 197 9.
If you require any clarification of the matters discussed herein, please contact C. J. Heltemes, Jr.
M. Heltemes' phone ntr:1ber is (301) 492-7745.
Sincerely, h$d) V
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D.' F. Ross, Deputy Di rector Division of Project Management Office of Nuclear Reactor Regulation Enclosure :
As stated 790607066G 169 052
ENCLOSURE ACRS RECOMMENDATIONS A.
Letter, M. Carbon to Chairman Hendrie, dated April 7,1979 Recommendation 1 - Perfom further analyses of small break transients and accidents.
Recommendation 2 - Provide operator additional infomation and means to follow tie course of an accident; as a minimum, consider expeditiously:
(a) unambiguous RV level indication
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(b) remotely controlled vent for RCS high points Re';omendation 3 - Item 4b of Bulletin 79-05A considered unduly pre-scriptive in view of uncertainties in predicting course of anomalous small break transients / accidents.
I B.
Letter, R. Fedey to Commissioners, dated April 18, 1979 f
Recommeridation ~. - Natural Circulation-related Items i
a.
Detailed analyses of natural circulation mode, supported as required by experiment, by licensees and NSSS vendors.
b.
Develop procedures for initiating natural circulation.
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c.
Provide operator means for assurance that natural circulation has been established, e.g., by install-i ation of instructions to indicate flow at low
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velocities.
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Expeditiously survey operating PWR's to determine whether suitable arrangements of PZR heaters and reliable on-site power distribution can be provided to assure this vital aspect of natural circulation capability.
e.
Operator should be adequately infomed concerning RCS conditions which affect natural circulation capa-bility, e.g.,
(1) indication that RCS is approaching saturation condition by suitable display to operator of
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T &T and PZR pressure in conjunction with h
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(2) use of flow exit temperature indicator by fuel I
assembly thercoccuples, where available, i
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169 053 i
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y Enclosure - page 2 s
j ACRS Recommendations Recomendation 2 - Thermocouples used to rneasure fuel assembly exit terrperatures to determine core performance should be used, where currently available, to guide operator j
concerning core status (full range capability).
Recorrendation 3 - Operating reactors should be given priority regarding definition and impleinentation of instrumentation to I
diagnc a and follow the course of a serious accident, t
inclu :S.g (a) improved sampling procedures under accident L,
conditions r
t (b) improved techniques to provide guidance to j
offsite authorities.
s' Recomendation 4 - Reiterates previous recommendations that high priority n
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be given to "research to improve reactor safety" I
(a) research on behavior of LWR's during anomalous j
(b) NRC to develop capability to simulate wide range of postulated transients and accident conditions.
Recomendation 5 - Consideration should be given to additional monitoring of ESF equipment status, and to supporting services, to help L
assure availability at all times.
i C.
Letter, M. Carbon to Acting Chairman Gilinsky dated April 20, 1979 Recomendation 1 - Initiate imediately a survey of operating procedures for achieving natural circulation, including:
(a) event involving less of offsite power (b) consideration of role of PZR heaters.
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