ML19224A866
| ML19224A866 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/17/1979 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Sherwood G GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 7906070061 | |
| Download: ML19224A866 (3) | |
Text
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!" 3 c( [,j NUCLEAR REGULATORY COMMISS!ON s
WASHINGTON, D. C. 20555
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MAY 171979 Dr. Glenn G. Sherwood Manager, Safety and Licensing Operation General P ectric Company 175 Curi.ser Avenue San Jose, California 95125 Dear Dr. Sherwood-
SUBJECT:
ACRS RECOMPINDATIONS RELATING TO TMI-2 ACCIDENT As you know, the Advisor / Comittee on Reactor Safeguards (ACRS) has written three separate latters to the Comission relating to the TMI-2 accident. These letters were issued on April 7, April 18, and /pril 20, 1979. Each of these letters contains specific recomendations which must be addressed. Tae ACRS has discussed these recommendations with the staff and industry at recent ACRS subcomittee and full comittee meetings. We anticipate thet this dialogue will continue in the for*.h-coming ACRS subcomittee meeting on TMI-2 (Pay 31-June 1).
For this reason, we are requesting that all light water reactor vendors provide the staff with a concise discussion and position on cach of the ACRS recommendations relating to THI-2.
For your convenience, we have provided in the enclosure a list which contains each ACRS recomendatio'1 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 Pc 23, 197 9.
If you require any clarification of the matters discussea' herein, please contact C. J. Hel' emes, Jr. Mr. Heltemes' phone nirber is (301) 492-7745.
Sincerely, s
D. F. Ross, Deputy Director Division of Project Panagement Of fice of Nuclear Reactor Regulation
Enclosure:
As stated 169 055 N
7906070 %l
r ENCLOSURE
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ACRS RECOMMENDATIONS A.
Letter, M. Carbon to Chairman Hendrie, dated April 7,1979 Recommendation 1 - Perform further analyses of small break transients and accidents.
Recommendation 2 - Provide operator additional information and means to follow the course of an accident; as a n.inimum, consider expeditiously:
(a) unambiguous RV leve'. indication (b) remotely controlled vent for RCS high points Recommendation 3 - Item 4b of Bulletin 79-05A considered unduly cre-scriptive in view of uncertainties in predicting course of anomalous small break transients / accidents.
B.
Letter, R. Fraley to Commissioners, dated Acril 18, 1979 Recommenda ion 1 - Natural Circulation-related Items a.
Detailed analyses of natural circulation mode, supported as required by experiment, by licensees and NSS$ vendors.
b.
Develop procedures for initiating natural circulation.
c.
Provide c.erator means for assurance that natural circulation has been established, e.g., by install-ation of instructions to indicate flow at low velocities, d.
Expeditiously survey operating PWR's to determine whether suitable arrangements of PZR heaters and reliable en-site power distribution can be provided to assure this vital aspect of natural circulation capability.
Operator should be adequately informed concerning RCS e.
conditions which affect natural circulation capa-bility, e.g.,
(1) indication tha RC' approaching saturation condition by suitable display to operatcr of T &
T., and FI? pressure in conjunction with SEeamtables (2) use o f fl o.. e xi: temperature indicator by fuel assemoly trer:::ouples, wnere available.
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ACRS Recommendations Reccmmendation 2 - Tnermocouples used to measure fuel assembly exit temperatures to determine core performance should be used, where currently available, to guide operatcr concerning core status (full range capability).
Recommendation 3 - Operating reactors should be given priority regarding definition and implementation of instrumentation to diagnose and follow the course of a serious accident, including (a) improved sampling procedures under accider*
conditions (b) improved techniques to provide guidance to offsite authorities.
Recommendation 4 - Reiterates previous recommendations that high priority be given to "research to improve reactor safety" (a) research on behavior of LWR's during anoma',t :s transients (b) NRC to develop capability to simulate wide range of pustulated transierits and accident conditions.
Recommendation 5 - Consideration should be given to additional monitoring of ESF equipment status, and to supporting services, to help assure availability at all times.
C.
Letter, M.
Carbon to Acting Chairman Gilinsky dated April 20, 1979 Recommendation 1 - Initiate immediately a survey of operating procedures for achieving natural circulation, including:
(a) event involving loss of offsite power (b) consideration of role of PZR heaters.
169 057
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