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Denwood Ross, Assistant Director for Reactor Safety, Division of Systems Safety ROUND ONE QUESTIONS ON GSAR-205, DOCKET NO. STN 50-561 Recently you forwarded requests (No. 212.167 and 212.183, copy attached) on BSAR-205 that eealt with power level assumptions for accident analysis and with iraplied comon mode reactor coolant pump component seizures due to earthquake accclcrations.
Request No. 212.167 concerning the 3800 Mwt power level appears to be in-consistent with, or at least casts uncertainty on, staff guidance given to applicants in Regulatory Guide 1.49.
If there is further consideration to be given to the guide, sucn consideration should be given and agreed upon within ONRR before we pursue the question with vendors. A clarification may be needed as to whether or not the thermal power added to the reactor coolant by the reactor coolant pu:rps sneulo be included in some accident analyses. Pending further discussion and resolution of this question, we have withheld this request from transmittal to B&W.
The second request (212.183) concerned potential earthquake induced pump failures resulting in the analytical equivalent of simultaneous locked rotors in more tnan one pump. As you are aware, the accident inferred by this request has not previously been considered in accicent analyses for PWRs, and it is not clear hcw the response to this request will be used in the context of any current standard review plan. Although we may agree that this accident shoulo be included as a design basis accident, it would be a significant addition to current review practice and should ba thoroughly considered and uniformly accepted throughcut ONRR. We feel that the Regulatory Requirements Review Committee should act on this matter.
If agreement is reached to nursue this issue on a case-by-case basis, ua feel that the concern should be addressed to all PUR vendors on a schedule tnat allows sufficient time for evaluation (probably at the acceptance review).
We have sent Request No. 212.183 to B&W, because it is at this time a request for a vendor evaluation of a portion of their system design. However, Regulatory review on a broad basis within ONRR should take place before a position is taken on this matter.
ow.o s~.nw R. C. DeYoung, Assistant Director for Light Ncter Reactors Division of Project Management i
Enclosure:
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BSAR-205 ROUT;D 1 REQUEST FOR INFORMATION 212.167 The total NSS thermal power, including 20 MWt for the reactor (13.1) coolant pumps, is 3820 MWt.
Why wouldn't 1.02 x 3820 = 3896 MWt be more appropriate as an initial condition for power level (versus 1.02 x 3800 = 3876 MWe)?
_12.183 Page 15.1.5-1 states that the frequency of occurrence of a single (15.1.5) reactor ccolant pu=p locked rotor is expected to be the same as
' any gross mechanical failure of the primary system.
The concern is that the potential for this event could be high in more than one reactor coolant pu=p during a seismic event.
Table 3.2-4 idestifies the pressure-retaining portion and the flywheel as seismic Category I.
Examine the non-Category I components (punp motor, impeller, shaft, etc.) and discuss the potential for seizure of pump / motor components during a seismic event.
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Central Files LWR-1 File J Stolz
.s,,,,T Cox H Smith (2)
S Burwell W Kane R Martin I Peltier C Stahle J Thomas R DeYoung T Novak S lsrael G Mazetis K Kniel 0 Parr W Butler D Vassallo 5
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