ML19210A327
| ML19210A327 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/19/1976 |
| From: | Arnold R METROPOLITAN EDISON CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| GQL-1407, NUDOCS 7910290561 | |
| Download: ML19210A327 (4) | |
Text
u.S. NUCLL A R H E GUL ATGn v <
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' NRC DISTRIBUTION FCH PART 50 DOCKET MATERI AL TO:
FROM:
oATE Or COCU'nE NT Mr Reid Metropolitan Edison Co 10-19-76 Reading, Pa R C Arnold oATE nEcEivE50-21-76 NecTTEa ONoToaszE o.
ance iNeuTFoRM NUMBER oF Copies ACCEIVEo
%onsciNAL SluNC L AssiriE o CCory 1 signed oE SC hip Tion ENCLOSURE Ltr trans the following:
Discussion of maggins available to cover the rod bow penalty... 6 a request that tech specs Change #36 be withdrawn.......
e PLANT NAFJ.:
Three Mile Island #1 1488 193 SAFt.TY FOR ACTION /INFORMATION ENVTun 10-23-76 ehf ASSIGNED AD:
l ASSIONED AD:
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BRANCH _ CHIEF:
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(8I BRANCH cMT7F?
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PROJECT MANAGER:
7.ove.#Y3.iA PROJECT MANAGER!
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INTERNAL DISTRIBUTION WREGlIW SYSTEMS SAFETY PLANT SYSTEv9 SITE SAFETY &
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NRC PDR HEINEMAN T nesen ENVIRO ANALYSIS
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SCHROEDER BENAROYA DENTON & 'fUT T FR gRELD L\\E!AS
'/ GOSSICK & STAFF ENGINEERING IPPOLITO
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MIPC MACCARRY KIR G.QQD FRN9T CASE KNIGHT BALLlRD HANAUER sit'WEIL i OPERATING REACTORS SPANCT TR 1RRLESS PAWLICKI _
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PROJECTJ\\NAGE}ENT REACTOR SAFETY OPERATING TECH.
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no, roa ~cnnss METHOPOLil AN EDISON COMPANY POST OFFICE BOX 542 RE ADING, PENNSYLV ANI A 196C3 TELEPHCNE 215 - 929-0601 wn Lo1 Cetater 19, 1976 Direetcr of Nuclear Reactor Reg 21stien Attn: Mr. Ecbert W. Ee'.d, Chief Operating Reactors 3 ranch No. h U. S. Nuclear Reg;1atory Cc ission Washington, D. C. 20555 s-
Dear Sir:
Three Mile IsJ.and Nuclear Station Unit 1 (21I-1)
Oceket No. 50-259 Cperating License LPF-50 Technical Specification Change Reques 36 Pursuant to the telephene conversatien between Mr. R. Labelle and P.
Landry of the NRC and representatives of the Eabecek & Wilecx Cc pany, the attached discussion of margins available to cover the rod bev penalty is forwarded. Further cre, we request that Technical Specification Change Request No. 30 be withdrawn frcm consideration.
Sincerely, n
.n
\\ '
C.
fnc d Vice President j
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M RCA:JJM:rk r/
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Enc 1csures
,' j cc: Mr. Welion 3. Arehart Mr. Harry 3. Reese, Jr 1488 199 1
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The 3RC - impcsed DU3R penalty for end-of-third-cycle has been calculated to be 10.L5 lased upcn the B&*4 bev divided by 138 times the CN3R penalty (at full closure) calculated for Ek'4 plants at 2hCO PSIA. The margins which 3F4 has identified to offset this penalty are as follevs:
Credit for ficv area reduction factor, PA, at 1.30 ENER
= 1.05 0:i33 7.5% ::i3R Available Vent 7alve Credit at 1.30 DUER
=
h.0% ::i3R Credit for elimination of densification pcver spike penalty
=
3.0% IN33 Credit resulting frc= analysis at higher than licensed pcver
=
(2568 rit vs. 2535 L'I)
TOTAL AVAILA3LE CRIDITS
= 15.5% D:i3R The following discussicn provides documentatien for the claimed 7.5% credit available from eliminaticn of the vent valve penalty.
This credit was esiculated en the basis of analyses perfor ed to define Technical Specificaticn Limits f:r Cycle 2 cperation of TMI-1.
on. a=c lm. _y
~1 =._.=r_n. a. Lm. v =.J' a.A =. =_
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mr The criginal envelcpe 6enerated by 3&*4 for Cycle 2 was based upcn the L Purp, open vent valve (ovv) limit curve, which incorporated a 19% D:IER Densification Penalty (and L.6% Vent Valve Flev Penalty).
The Limit Curve was defined by the folicving points:
Pressure (PSIA)
TOUT 1800 586.8 2000 606.h 2200 621.2 2hCO 63h.6 The ccrresponding variable low pressure trip setpcint is:
P = 11.75 Tout - 5103 (PSIG)
(1)
The revised envelope, provided in Cycle 2 Tech. Spec. Rev. 3 (and submitted by Met. 21. as Change Request 36), was based en the more limiting of the 3 or h Pu=p Limit Curves, which incorpcrated a 5 9% 0:!3R densification penalty and assumed closed vent valves. The limit curve was defined by the following:
Pressure (PSIA)
TCUT (3 Pump Case) 1300 589 3 2000 6CS.9 442. 1 conc v v.
--w 2kC0 635.7 The correspending variable Icv pressure trip setpcint is:
= -.'. t ~i,4 '.
u*. - h e' h
(' O. C 7. ' )
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0 s
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- 3&'d calculation - latest '!RC calcula:icn shcvs 11.25 penalty (end cf Cycle 3,'
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The available credit remaining frc= the unused vent valve credit was based upon the assumption that CC-1 was operating under the =cre restrictive of the tvc variable 1cv pressure trip setpcints (equatien 1).
Available credit was calculated by taking the " full vent credit" cf 11.5% less the difference in densification pensities between the original and corrected curves (115% - k5 = 7.5%). A subsequent analysis has shown that by utilizing equatien 1 the =argin between the corresponding 11:1t curve and 1.30 DNER is at least 8.5% for all pressures. For exa=ple, at 2000 PSIA, the maximum cutlet temperature is 621.2 F, as shown in Tech. Spec. Figure 2.1-3, and the corresponding MDN3R is 1.h1 for the closed vent valve case, including 5 9% densification penalty.
Thus the quoted available
" vent valve" =argin of 7.5% is valid hen equatien (1) is utilized as the variable icv pressure trip setpoint.
It is therefere recc== ended that the proposed P-T envelope presented in Change Request 26 be withdrawn in order to preserve this margin.
FI.Uv/r'_CW TRIP SE"DOINT The original setpcint specified for Cycle 2 cperation (1.08) was justified by a transient thermal-hydraulic analysis which assumed one cpen vent valve and a 1.95 CHER densificatien penalty. This analysis justified a maxi =u= alicvable setpcint (error corrected) of 1.C8.
When the densification penalty was revised to 5.95 (DU3R) a new T-H transient analysis was performed to justify the previcusly specified setpcint of 1.08.
This analysis incorporated the 5 9% densificatien penalty and assumed that all vent valves remain closed. The resulting MDUER cf 1.h7 de=enstrates that the mini =um available margin to DNB (1.h7 - 1.30) is greater than the 7.5% available vent valve credit quoted for coverage of the rod bcv penalty.
1488 201