ML20040A604
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NUCLEAll REGUL A'ORY COMMisslON
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- doc'ket flo s. 50-514/515 APR 2 31978
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.f MEMORAf'DL'" rC.
D. B. Vassalio, Astistant Director for LWR's, DPM i
J-FROM:
D. F. Ross, Jr., Assistant Director for Reactor Safety, DSS d
SUBJECT:
SER SUPPLEMENT IllPUT FOR PEBBLE SPRIflGS UNITS 1 Afl0 2 l
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Plant flame:
Pebble Springs, Units 1 and 2 4
Docket tios.:
50-514/515
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- i Milestone No.:
Licensing Stage:
CP Desponsible Branch LWR-4
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and Project Manager:
C. Stahle 8
Systems Safety Branch Involved:
Reactor Systems Requested Completion Date:
March 17, 1978 Review Status:
Complete 4
References:
1.
Pebble Springs Units 1 and 2 Safety Evaluation Report Supplement No. 4 2.
Memorandum from D. F. Ross, Jr., to D. B. Vassallo g
dated February 10,1978, "SER Supplement Input for j
Pebble Springs ~ Units 1 and 2".
?A 3.
Mec.orandum from E. G. Case to R. Mattson dated March 10, 1978, Request to Issue Revision 1 to SRP 5.4.7.
4 flemarandum from R. Mattson and V. Stello, Jr., to i
'4 E. G. Case dated January 19, 1978,.
M 5 Rcfereit-I describes the fourteen issues in the Reactor Systems Branch area.
'd j T' e ord i.mt submitted responses to these issues and the results of our revie'.. v t.hese responses was forwarded in reference 2.
The attached e,-
1 crq sy; al, re.it input contains our review of the 3 remaining issues:
i pssiv I tilures during long term cooling, feedwater isolation valves l-wi ChanNr 15 long term operator actions. We consider each of these ftens *es? ved.
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MADDEN 00-515 PDR J.. r '~.
D. B. Vassallo
-2 APR 2 31370 The applicant has transmitted a draft of their response on operator actions to expedite the staffs review. The applicant states that this draft will be formally included in Chapter 15 of the Pebble Springs PSAR in Amendment 11 which is scheduled for submittal by April 15.
Our acceptance of this area is contingent upon the formal submittal of this material as it appears in draft form.
Reference 3 directed that Revision 1 to SRP 5.4.7, Residual Heat Removal System, which incorporates Branch Technical Position RSB 5-1, be im-plemented in accordance with the schedule set forth in reference 4.
This BTP provides the new requirements for taking the plant from operation at power to cold shutdown, using safety-grade systems, assuming. only offsite or onsite power is available and assuming a single active failure.
I Reference 4 provides guidance for the partial implementation of the revised SRP 5.4.7 in the review of Class 2 plants (CP or PDA applica-tions docketed before January 1,1978 and for which an OL issuance is expected on or after January 1,1979). As a Class 2 plant, Pebble Springs must provide a commitment to meet this position prior to issuance of a Construction Permit. The specific review of this area would be carried out post-CP.
It is our understanding that DPM is implementing this position on a generic basis. We have, therefore, not included this area in our enclosed safety evaluation.
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D. F. Rast, Jr., Assistant Director for Reactor Safety Division of Systems Safety
Enclosure:
SER Supplement Input cc:
S. Hanauer G. Mazetis R. Mattson T. Novak D. Ross S. Israel S. Varga S. Newberry*
C. Stable
Contact:
S. Newberry, NRR x27341
Enclosure j
RSB SER SUPPLEMENT PEBBLE SPRINGS Item 6 - Passive Failures During Long Term Cooling The applicant has committed to meet the staff's acceptance criteria as described in reference 1.
This committment is acceptable at the construc-tion permit stage of review.
Item 10 - Feedwater Isolation The applicant was required to show that the closure characteristics of the feedwater control and block valves had been considered in the accident analyses requiring feedwater isolation. The applicant states that'the most limiting accident with respect fo feedwater isolation requirements is the main steamline break.
Feedwater isolation for this event is modeled as a 17 second ramp. The applicant also contends the feedwater valve closing time design specifications of 7.0,12.0, and 12.5 seconds for the main control valves, the bypass control valves, and the isolation valves, respectively, ensure that the analysis assumption is satisfied.
We will require that tests to confirm the closure times for these valves as well as the main steam isolation valves, be made a part of the plant Technical Specifications. We consider this concern resolved for the construction permit stage of review.
Item 11 - Chapter 15 Long Term Operator Actions Additional information was requested to provide a discussion for each Chapter 15
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event describing all of the actions in the recovery mode following a transient.
The staff's interest was in evaluating the operator's role in achieving and maintaining stable conditions.
a The applicant provides a discussion of all required and expected operator actions for bringing a plant to hot shutdown and cold shutdown conditions following each event (see cover letter regarding submittal).
Based on the information submitted, the automatic safety features incorporated into the Pebble Springs design provide sufficient operator time and indications.
Accordingly, we conclude that the applicant has provided adequate assurance of long term operator response at the construction permit stage.
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