05000263/LER-1977-025

LER 77-25:on 770913,recalculated ECCS Thermal Limits Found to Be More Restrictive than Tech Spec Limits.Limiting Break Size & Revised Thermal limits.W/770927 Ltr

ML20056B866
Person / Time
Site:	Monticello
Issue date:	09/27/1977
From:	Mayer L, Voth M NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
LER-77-25, NUDOCS 9102130536
Download: ML20056B866 (2)

LER-2077-025,

Event date:
Report date:
2632077025R00 - NRC Website

text

_ _

i 6 .

l l

l LICENSEE EVENT REPORT '

CONTROL BLOCKl 1

l l l l l )6 [PLEASE PRINT ALL REOUIREO INFORMAT L CENSf E Naut LcENSE NUMBEA YE

@ IM l ul W NI Pl il T FE 7 89 14 lo 15 f o l-l olo l ol of 01-101 o f L411 1111111 25 26 101 11  !

30 31 32 CATECOAV 77P DOCufi NUMBER

@ CONT [ l l 7 8 EVENT DATE REPOAT DATE 57 58 59 60 l 015101-10 l 2 l 613l 61 68 l0 l 9 l 113l7 74l 7175l Ol 9l217 l 7l 7l 69 EVENT DESCRIPTION 80 7 BE 89IThe re-calculated ECCS thermal limits were found more restrictive than tech spec l l

$ 89 llimits at certain exposures for fuel types in service at Monticello. Until tech 80 7

l 7 8 [snec revisions are issued. the more restrictive of existing 80 and proposed limits willl i

@9lhe administrative 1y implemented. No previous occurrences.

7 8 80 '

(M-RO 25)

@9 7 89 l

83 l

Pswf i )

E C[of 80 [

CcMPCNENT CODE uppuER V NUs E Iz1 d lCJ 7 89 10 11 Izlziziz1zlzl 12 (z_J Iz I 91 919 l U R VOLATON L;gj f

i 17 43 44 47 48 '

CAUSE DESCRIPTION 7 DE 89 ( Additional break sizes analyzed to better define the response over the brea 7@89 lrum, ubile implementing approved model changes, ea

' resulted in a revised limiting bread {

@ (size and revised thermal limits. 80 saCiuTv j STATUS  % PCWER METHOD OF 8

7 8 9 hj 10 bioloi i n DTHER STATUS I

O'SC0vtav Ln_I In DrSCOVERY DE SCRIPTON I

12 13 44 I  !

45 46

83

$EtrYSlo ENI't2ISE AuoVNT OF ACTWV 35 7 8 tzJ 9

LzJ 10 11 ln 1 In LOCATON OF AELE ASE i

44 45 I FERSONNEL EXPOSURES 83 NVMBEA 7tPE DE SC AfPTON 8 10101 01 LZJ 7 89 11 12 l NA 13 J

PERSONNEL INJURIES la i

1 NUMBER DE SCRIPTON 81010101 7 89 11 12 In l

3 OFFSITE CONSEQUENCES 80 EE l n 7 89

,) 1 i

LOSS OR DAMAGE TO FACILITY so TvPE DESCRIPTON 3 [zj (_ NA 7 89 10 j l PUBL!CfTY

' 8a I NA i 7 89 l

I ADDITIONAL FACTORS C j 1

7Q89 l Complete ECCS analysis was submitted to Mr V Stello (USNRC) byj L 0 M i e

19 l'*3ep tembe r 15, 1977. 9102130536 77092 63 CF ADOCK 050 263 7 89 p

~" l 60 i

_. . . - .- , _, - _ - - - -- ~~ ~^

/ , ,T' 4A /

< p- Q, ), s- s

• . . f, t

()

NSP[

~

NORTHERN STATES POWER COMPANY M I N N E A PO LI S. MI N N E G OTA 39401 September 27, 1977 Mr J G Keppler, Director, Region III Office of Inspection & Enforcement U S Nuclear Regulatory Cor:nission ,,g(,' '

799 Roosevelt Road Glen Ellyn, IL 60137

Dear Mr Keppler:

MONTICELLO NUCLEAR GENERATDiG PLANT Docket No. 50-263 License No. DPR-22 Revised ECCS Limits The Licensee Event Report for this occurrence is reproduced on the back of this letter. Enclosed are three copies.

Yours very truly, L 0 Mayer, PE Manager of Nuclear Support Services LOM/deh cc: Director, IE, USNRC (40)

Director, MIPC, USNRC (3)

G Charnoff MPCA Attn: J W Ferman

~

C. ..

, . a, j ly 'e

- - - _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ .