ML20126K461
| ML20126K461 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 05/08/1981 |
| From: | Morisi A BOSTON EDISON CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.16, TASK-2.K.3.18, TASK-TM 81-92, NUDOCS 8105150150 | |
| Download: ML20126K461 (3) | |
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BOSTON E* DIS O N COMPANY OswanAL Orrects 300 BovLeTON STRtt?
SceTON. Mase AcNue tTTS O219 9 A. V. M O RIS1 MANAGER NUCLEAR DPERATIONS SUPPORT DEPARTMENT May 8, 1981 I
BECo. Ltr. #81 92 2
Mr. Darrell G. _ Eisenhut, Director Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555 License No. DPR-35 Docket No. 50-293 l
Response to NUREG-0737 Items II.K.3.16 and II.K.3.18 Reference A: BWR Owners Group (D. B. Waters) to NRC (D. G. Eisenhut), "BWR Owners' Group Evaluations of NUREG-0737 Re-qui rements II.K.3.16 and II.K.3.18",
dated March 31, 1981
Dear Sir:
Reference A, submitted by the BWR Owners' Group, contained feasibility studies on Items II.K.3.16 " Reduction of Challenges and Failures of Relief Valves" and II.K.3.18
" Modification of Automatic Depressurization System Logic". Attached please find Boston Edison Company's position relative to these studies.
Should you desire additional information or clarification on this subject, please feel free to contact us.
Very truly yours,
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THIS DOCUMENT CONTAINS
' p 10 515 0.-)S4 P00R QUAUTY PAGES I
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3 II.K.3.18 The Reference A feasibility study on possible modifications to the automat 1c l
cepressurization system logic identified three optior,s, including retainir.c i
the current desien, as viable aporoaches in oroviding assurance that adequata j
': ore cooli;; is maintnined c;rir.g. eveats which cc not produce c hich drywi' presssa sis;ra; and are degrace: by a loss of all nian cressure ccolinc systems.
i Boston Ecison Corcany believes that the current Pilgrim Station ACS locic desien l
coupled with impie:r,entation of tne synptoa-oriented Emergency Proceduce SuNelines will sctisf/ the NUREG 0737 requirements of assuring adequate core coolina ;urir,a the events in question. This position is formulated on the fact tnat events of this type are slow, unconolicated and familiar transients for which the operator is extensively trained and for which he is faniliar with both the eouionent i
respcnse anc the overall system resoonse 2nd behavior.
Because of this familiarity.
the relid>ility of the operator to perform the required actions is.)ign, to the
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point of being reflexive. Sufficiciit time is available (30 to 40 minutes) to assess the overall plant situation and initiate blowdown if required. The current design also allcws thc operator the flexibility to ccntrol the systems as require; by the plant conditior.s and syrptoms and in addition, the Emergency Crocedure Guidelines, wnen implemented. will provida further specific guidance on when to initiate ADS.
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The Reference A study identifies the reduction of Stuck OJen Relief Valve (SORV) events as' the in:ent of the NUREG item and presents vari'ous methods of educinq l
the likelihood of such events, i.e. reducing challenges to S/RVs, reducinc causes i
of soarious blowdcar.s and reducing the probability of S/RVs to stick ccen wher, j
c.lall enge d.
Scsed on this infomation, c e believe that a s t.bnarcial rec ;;;io,1 I
' by an 'crder of racnitude) in ice incicer.ca of SCT/s is cessible.
3ilcri:, S tation it a the following n.ethods:
1.) Change top <orks of the' three stace Target Rock valves to ;wo stage.
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Comment - This change has already been made at l
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Pilgrim.
l 2.) Low-Low set relief or equivalent manual actions l
i Com:ent - Current Station operating procedures call for manual opening of a relief valve under condi-tions which are likely to cause auto actuation and the BWR Emergency Procedure Guidelines, when imolemented, will orovide further ass.r-ance of reducing the total number of S/RV challanges by limiting the second and tub-secuant opening of the S/RVs tc teet the intent of the Lo s low set valve.
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