ML20024B467
| ML20024B467 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/10/1979 |
| From: | Taylor J BABCOCK & WILCOX CO. |
| To: | Fraley R Advisory Committee on Reactor Safeguards |
| References | |
| TASK-03, TASK-06, TASK-3, TASK-6, TASK-GB GPU-0265, GPU-265, NUDOCS 8307080790 | |
| Download: ML20024B467 (2) | |
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,nc--s z. Ya. 2ases Te.e:r:ws:c :s4 :::t Cece..ter 10, 1979 Executive Director
!FiDENTiAL CONRDpJ1T *il Mr. Rayxend F. Fraley u-Advisory Cocittee on Reactor S U.S. fluclear Regulatory Co=f s W,r,ts, R O B 2
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'Jashingt:n, D.C.
20555
Dear Mr. Fraley:
This letter is in response to ycur.muest (letter, R. F. F-aley to J. H. Taylor, Septeeter 14,197?) fc.- inferr.tti:n regarding ;rcoability studies performed by the SCl Cc..:pany.
The first iten of your letter requested infor ation regarding studies perforud which either confirms the failure data used in WASH-14C0 or
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indicates it should be revised.
32.'1 has perfomed a probability analysis i
en the failure of a FORY (Pilot 0;ersted Relief *!alve) to reclose. Tne analysis was based u:cn historical reactor trip and turtire trip data i
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experienced cn 6El plants. The resul t of this analysis incicatas that the i
PCRY's failure to reciese, en a per der.and basis,2, gns.1:00 calcutation is censiste.t with the value cited in VASH-14C0 (Sci calculati:n 2-4x10-1x10-2 wi th an erro r f ac tor o f 10). It srculd be n:ted that loss of feec-water transients which lift the FCRY hace been essentially eliminatec by the revised PCRV and reactor trip set;oints. Tnis revisien significantly reduces the ex;ected tu-der of dacteds ;1 aced uoan the FORY and therefore the anticipated nu.-ber of PORY failures to recicsa nas bee.1 essentially ella.inated for these tr:nsients. 3Ei has not perfor ed any other analyses
'a detemine the validity of failure data in *. DASH-1400.
With regard to the second ites of your letter, 3C1 has perfor:ed an extensive deterministic analysis asse:iated with the transients idantified l
by Congressman (;dall, but we have r.ot ;trfor ed any ;ro:a:flis tic analyses directly related to these traasien's. EEi has perf:rred a. study for E7R' titled, "Prcbabilistic Accicant Analysis - Al'.is," EFRI :;7-1090. Interim Report, June 1979, shicn identifies t..e fre uancies Of s:e:ific antici-l I
pated transients based upon actuai 3Ci :;erating ex;arienca. Ia fe ma rd-ing to you a.c:;y cf this re; rt f:r y:.r use.
It should be noted that 95W 5.as untertakan several studies uhich are directly rela ted to sys ten relitoility i revccents. Sc e of these are Auxiliary rect.va ter Sys te.- Reliability 2nalysis, In:cgrate: Con trol Sys ten failure rudes and Effects Analysd an: the Abncr ai Transients 6 erat:r Guidelines Program. To date, the results of the auxiliary faec.atar systen i1 8307080790 791210 PDR ADOCK 05000289 l
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p Sabcock &'.'li cox r.r. Raycond F. Fraley Page 2 C-ect-ter Iq,1973 reliability study have identified areas uf ch fr: rove reliability..Many changes ha.e been =ada and =re are being ::nsidered wnich will affect auxiliary feedsater system reliability.
In addition, the *!RC has ini tiated *ta Ir.tagra ted.~.el tatii t ty Evaluaticr.
Program. IRF.P. wnich essentially consists :f a c:ni.,'AIN.W~, anal sis en
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all operating plants. It is anticipated t at these studies -ill aid in addressing your concerns in the future.
Please ccatact me if you have any c:r.: erns regarding this inf:r.ati:n submittal.
Ve r-truly yours.
/ /
./h!lO AY/f Ja.v..s H. Taylor
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