ML20205D381
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DFF t.00-02423 June 1985 l
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3A?gTY ISALVATION FOR PILGRIM l
PRR IWP MPASS VALTES i
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IMPACT ON LPCI OPEFATION pemoving the automette signn! to : lone the RHR etnizan flow bypass valves will result in the talves reesin17s open during the L7C1 operation. This in effect will redace the aasunt of LPCI flov into the reactor vessel hy the flow through the einieua bypass 1*nes.
The bypass flov is 525 spr per pux; at lov flos condittens, which is approxir.ately 10% of the rated flev for each P.HR pu:7 At high flow conditiese, the bypass flow will be reduced because the punpa vill deliver lower head.
For example, if two t
purpe are cperating at rated flow conditions, the bypase flow for each pump will be redu:ed to approxinately JnD sp=.
Neverthelese, it to assumed fer added eeneervaties that the bypsen flow is at 525 Apr for all pu p flow cerditions. Housser, this potential reductf en of the MA purp parfor:ence has insignificist effe:t on the plast's core cooling capability. Thi$ it de ai,etrated by the fo1I6*g evaluation of the row RHR pue; perforrence for postulated large, inte nediate and e-all break events. Table 1 prevides a sa:=ary of the evaluatjen.
The : st lic'iting accident esert for Pilgrit is the =ssitue recirculation auctien line bre4k vich an assumed single failure of the LPCI injection valve. For this event, no L?C1 inje: tion flov is assured and the reduction in L7CI fles is of no consequence. For the next liniting large break occident, the assured single failure is a diesel generator railure.
The operable systers ara H7CI, At$. ene core spray pump a94 two LTC1 pu 79.
The reduction in the LPCI finv =sy in:rease the cara uncovery ti!.9.
Novever, pis9e specific cniculatiosa for Pilgrim derenstrate that the stall increase in core uncovery time intresses the peak cladding te=perature 1
(PCI) by approstretely 50*F.
Since the FCI for the LPCI fathre to higher j
then ths PCI for the diesel generator failure by over 160'F, tne reductien
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in the LPCI flow will not cause ths large break event with diesel generator l
failure to becces the liri 19s eveit.
I For the case of interuediate breeks vtth e diesel generator failure, the nov ANR pu p perfotuence toy result fii e FCI increase of 091y SI'F.
Howeser, the differen a bet CT for the interwediare braak esente FOR IMoRMITION
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TA3L1 1
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PESULTS OF PPOPOSED H0DIFICATION 0:4 1
FILGPIM PrR MPASS VALVE i
PEAX C.ADDIh'G TDGEMm1 ('P)
SLCIION LINI SIh3LE SYS7Df9 BEFOPE AFTER BREAF SIZC PAILU3[
AVAILABLE NODIFICATI0'l
_M 1:)! FIC ATIO*J
. Large I.PCIIV 2Cs 2136 2126 i
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!CS+2LPCI 1974 2024 Interradiate DO IC!*2LPCI 1767 1A23 Senil hPCI ADS +2C5+4LPCI 1615 1670
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and the lir.iting large brea', sventa are larger than 300 F.
Thorsfore, the reduction in the L?CI flev vill not cause the inter =ediate break case to becere the ifritina event for Filgrie.
For the case of stall break eventa, the increase in FCI is appropirately 55'F.
Havaver, this is not a significent effect en the plant's core cooling carseity. This is becauss, for nr.all breaks, the two cora spray purps are e.sre than adequate fer cera cooling.
It should be noted that s. realistic analysis (perforced with SAFEA/0157R or with realistic inputs and asstarption with SAFE /PPFLOOD) would indicate that en) eingle Inv pressara punt (LPC1 or core spray) would provide adequate cora cooling Aor rost accident events (See NEC-30936P, "BWR Cvnste' Crour t
Teebnical St.ecification Teproveceit Methodology". November 1985,'.
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SUBJECT:
PNPS Technical interpretatien Applicab'e Tech Spec. 4.$. A.3,d INTERPRETATION:
PDC 86-33 modifies the LPCI $yhtem configuration to maintain tre minimum flow bypass vaitres open during LPCI injection.
The current ccnfiguration of the LPC1 System has tha minimum flew bypass valves closed during injection.
With the folicwing interpretation cf the technical specification (Section 4.5. A.3.d), it is concluded that the prepos00 design change does not re:;uire a technical specification changt.
AMA'.YSIS AND BASES FOR INTERIRETAT!QN_
1he 14.400 QDM curp desicn e30acitv. as required by the tett.nic51 specifications, was used in the initial core LOCA analvsis as the total flew to the sessel. The origirsL ere 10CA ana19 sis did show that this fics fNF _
_three LCCI pumos_ (4.600 gpm per pump; 14,400 f or 3) by themselves.would maietiin ruei elad temceratures below the original acceptance criterta of
_27000F.
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The design maximum te?.perature criterion of 2,7000F was satisfied with a large margin across the entire spectrum of possible liquid or steam line break sizes by at least two separate and independent systems, and by two different medes of core ecoling, even in the event of tne loss of of fsite auxiliary power.In additien, redundancy in the systems existed since only one of the two 100 carcent capacity Core Spray Systems, or three of four available LPCI pumps, er a ccebiration of one core spray pu :p and two LPCI pu Ts, were needed.
Eith the promulgation of the present 10CFR50.46 criteria and_ Appendix K methods, the LOCA analysis was redone to show conformnte with the new criterien of 2200cF Deak Clad temperature. _A change was also ade in the selecticn of available systees~to be used in the aralysis.
Single failures in the total ECC5 syste?s were assuned together with a loss of off site power to define the systems remaining operable, the single failure situations considered are:
Failure Systems Remining Operable LFCl injection valve 2 LFCS + HPCI T ADS (ko LPCI tumn available)
Diesel Generator 1 LPCS + 2 LPCI + HPCI + ACS HPCI 2 LPCS + 4LFCI + ADS r-FOR iNFORMA7ON 0W y" t
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Page 3 PWPS Technical $pec. Inter.
Applicatie Tech. Spec. 4.5.A.3.c As can be seen from the above tratrix, either no LPCI injection flow is credited (LPCI injection valve f ailure) or two LPCI pumps are credited (diesel failure) or all four RHR peps are credited (HPCI failure). The failure of a 4
singla LPCI pump with coincident less of core spray (leavthg three t.PCI pumps) while analyzed in the original LOCA, is reyend the present design btsis and is therefore not used in the 10CFR Appendix K analysis.
The N dification of LPCI system by PDC 86-33 results in scoe of the LPCI flow being diverted to the torus through the normally cpen ninimum flo.i lines..Tfh.t.
I_ ntest G.E._Accar.Ain k 100A armlytit ceneludes that cote 9tial r,(d4ction of
_LFCI ficw throuah mini v flew linet has an insienificant affert en the]
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_ plant's core coo 1*ra catacitv.
Ageln, the design capacity of LPCI pu'.ps. (on 1
a per purp easis 4600 gpm per pu?p; 14,400 for 3), as included in the tech.
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spec., was used in the Tatest G.E. Appendix x LOCA analysis as total pump discharge, t
uC C.0SION Saseo en the above, it is cencluded that surveillante testing of the LPCI
_ system is earr* " thew that the des ten flow (4800 gpm per p'ap);en De_
.a ttained at the em Mit e*ar-*.
Th4s ficw is indicative of pur'p capacity and does not rafiart the actual flew ~recuired to be injected into the vessel..The
~ latest rd Ateerdix ( analytit da'rsnstrates that adecuate core cooling if paintairt-durino LFCI syf te.n coeratien wjth the r-iniM fle.t bypass line Tselatien valves eden. The prose.it Tech. Spec. Surveillance Test is censistent with the requirement to show adequate pu*o discharge capability ard continues to be consistent with trie 'ech. Spec. bases 3.5. A anc requires no i
changes as A result of this modificaticn.
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O 94o PILGRIM STATION NPD TE1.EPMCNE CALL RICORD l
TO Mr. Paul Leech DATI 7-21-86 TIME F 19 n m N.R.R. Bethesda rac3 Richard Vdlez
_ COMPMN/0PTIC SU3JICT:
Fire Watch Training / Appendix 'R' Exemption Request PHCN4 No, 9 -9416 R. Velez called Mr. Leech to reaffirm discussions with respert to trainino of Appendix 'R' Fire watches.
It is understood that fire watches will be trained in the use of portable fire fighting equipmen* (i.e. fire extinguishers) and instructed in the proper application of same.
8e Mr. Leech ecknowledged Boston Edison Company's understanding on this issue.
Accio Required:
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(No)
Copies To:
R. V51ez T. Ferris W. Sullivan b
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R,N. Swanson v.D. Keyes v
'N A. Pederson E. Ziemianski pA t 7 -22.- 96 C.$rono Tile No: MiiiP Subjee: Tile No:
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