05000263/LER-1976-012, Updated LER 76-012:on 760805,generic ECCS Model Analysis Indicated 2200 F PCT May Be Exceeded at Reduced Core Flows. MAPLHGR 5% Reduction at Less than 90% Core Flow implemented.W/760910 Ltr

Updated LER 76-012:on 760805,generic ECCS Model Analysis Indicated 2200 F PCT May Be Exceeded at Reduced Core Flows. MAPLHGR 5% Reduction at Less than 90% Core Flow implemented.W/760910 Ltr

ML20086D505
Person / Time
Site:	Monticello
Issue date:	09/03/1976
From:	Mayer L, Nevinski D NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20086D508	List: 05000263/LER-1976-012, Updated LER 76-012:on 760805,generic ECCS Model Analysis Indicated 2200 F PCT May Be Exceeded at Reduced Core Flows. MAPLHGR 5% Reduction at Less than 90% Core Flow implemented.W/760910 Ltr
References
LER-76-012, LER-76-12, NUDOCS 8312020183
Download: ML20086D505 (2)

LER-2076-012, Updated LER 76-012:on 760805,generic ECCS Model Analysis Indicated 2200 F PCT May Be Exceeded at Reduced Core Flows. MAPLHGR 5% Reduction at Less than 90% Core Flow implemented.W/760910 Ltr

Event date:
Report date:
2632076012R00 - NRC Website

text

'

UPDATE REPORT PREVIOUS REPORT DATE 08/11/76 LICENSEE EVENT REPORT CONTROL BLOCK:l l l l l l l (PLEASE PRINT ALL REQUIRED INFORMATION) 1 6 LCENSE NUMBER vE TYPE NAME

$ lM lN lM l NlP l 1l l 0 l 0l-l0 l 0 l 0l 0l 0l-l 0 l 0l l4 l1 l1l1l 1l 30 l0l1l 32 7 89 14 15 25 26 31 CATEcoRv TN Eub C3CmET NUMBER EVENT DATE REPORT DATE l 0l 91 d 3l 7l6 l O 1 CON'T l l l k_j M l 0 l 5 l 01-10 l 2 l 6l 31 10 l 8 l Ol 51 7l d 60 68 69 74 75 80 7 8 57 58 59 61 EVENT DESCRIPTION

@ l Generic ECCS Model analysis for BWR-3's indicates 2200 F PCT may be exceeded at l 80 7 89

@ l reduced core flows. A 57 reduction in MAPUIGR at less than 907. core flow has been 80 l 7 89 b l inniemented. This will continue until further analysis is completed. No previous80l 7 89 l

SE l occurrences (M-RO-76-12) 80 7 89 l

hl 7 89 pniu, 80 SUPPL R M R VOLATON C E CODE COMPONENT CODE

@ l 7] Z l [Z_j l Zl ZlZ lZ l Zl Zl 17 W 43 lZ l9 l9 l9 l 44 47 O

48 7 89 10 11 12 CAUSE DESCRIPTION gg l At reduced flows where the onset of transition boiling could occur, conservative l 7 89 80 3[ lheat transfer coefficients are applied which decrease heat transfer away from clad l 7 89 80 1O land increase PCT. l

% POWER OTHER STATUS DSCOVERY OiSCOVERY DESCRIPTON STA us b

7 8 d

9 l O! OI O l l NA 10 12 13 l

44 d45 lMA 46 80 l

R E SD 0 REL ASE AMOUNT OF ACTMTV LOCATON OF RELEASE H

7 8 IzJ 9

Ld l 10 11 m I 44 I

45 NA 80 I

PERSONNEL EXPOSURES NUMBIA T Y PE wi$cRIPTON l

DE l o lo 101 (ZJ I NA 80

? 89 11 12 13 PERSONNEL INJURIES NUM9ER DE SCRIPT ON DE 10l 0101 1 NA l 7 89 11 12 80 OFFSITE CONSEOUENCES l

BE hA 760903 80 7 89 B312O2018 LOSS OA OAMAGE TO FACILITY PDR ADOCK 05000263 PM T Y PE DE SCR.PT ON g 8 LzJ l 7 89 10 NA 80 I

PUBLICITY l

DE l NA 80 7 89 ADDITIONAL FACTOAS 18 l Subscouent to previous report. notification received that MAPLHGR reduction should l 7 89 80 Q l apply below 907. core flow rather than 857.. l 7 89 80 NAME; - D E Nevinski - PHONE:

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d NS58 NORTHERN STATES POWER COMPANY M I N N E A PO Li s. M I N N E S OTA Std 409 gf \ ..~

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September 10, 1976 ,

1'*!

t SEP131976x ii Mr J G Keppler Director, Region III u,s, t}gtg ;

M fma t,y[!

Office of Inspection & Enforcement \

U S Nuclear Re< g ulatory Comission Q7'[pgj/p/

u 799 Roosevelt Road Glen Ellyn, IL 60137

Dear Mr Keppler:

'MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Reduction in MAPLRGR Limits at Re duced Core Flow An Updated Licensee Event Report for this occurrence is reproduced on the back of this letter. Enclosed are 3 copies.

Yours very truly, L 0 Mayer, PE Manager, Nuclear Support Sarvices LOM/MllV/ deb cc: Director, IE, USNRC (40)

Director, MIPC, USNRC (3)

G Charnoff MPCA Attn: J W Ferman I

i 9324 i

iX)PY SENT REGI

/

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