05000263/LER-1977-023

LER 77-23:on 770909,RHR Torus Cooling Valve Mo 2009 Failed to Operate Properly.Caused by Inadequate Stem Clamp Set Screws for Unseating Torque.Stem Clamp W/Keyway Being installed.W/771007 Ltr

ML20056B865
Person / Time
Site:	Monticello
Issue date:	10/07/1977
From:	Mayer L, Tilly D NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
LER-77-23, NUDOCS 9102130530
Download: ML20056B865 (2)

LER-2077-023,

Event date:
Report date:
2632077023R00 - NRC Website

text

6 LICENSEE EVENT REPORT CcNTnOt etOCol l l I I I l cpLemu cam Au neaumeo momanon) 1 6 dE LCENSE NUMBER YE T PE

@ lw Iw I Ml NlP l1l bl 0l-l 0 l 0l 0l0 l 0 l-l 0l 0l l4l1l1l1llj l0l 3l 14 15 25 26 30 31 32 7 89 DOCKf1 Nui4BER EVENT DATE REPORT DATE CATEGOQv iP 50 O 1 CON T l l l Q59 W l 0l 5 'O l-l0 l 2l 6 l 3 l l0 69 l9 l0 l 9 l 7 l7 l l1l 0 l 0l7 l7 l 7 l 74 75 80 57 58 60 61 68 7 8 EVENT DESCAIPilON l

@l During operation of system RHR torus cooling valve HD 2009 failed to operate gg 7 89 4 I properiv. Investitation revealed stem clano set screws had sheared allowing sten80l 7 89 l

EE l to rotate. Upstream isolation valve MO 2007 was operable at time of occurrence. eg l '

7 89 EE I Three previous similar occurrences (A0 74-02, A0 75-13 and RO 76-17). Stem eg l

7 89

@l clamp with keyway being installed to eliminate set screw problems. (M-RO-77-23) J pc. ,, eo 7 89 s R u NUF A votATow DI CD f COMPONENT CODE

@ l Sl Dl @ l Vl Al L] VlE lX l 17 W 43 l A l3 l 9 l 5l 44 47

@48 7 89 10 11 12 CAUSE DESCRIPTION DE l Stress analysis indicates stem clamp set screws not adequate for unseating torque.80l 7 89 33 l Anchor,10 inch, 300 pound globe valve. Stem clamp with keyway being installed 80 l

7 89 H l to eliminate set screw problem. l METHOD OF FACIUTV D!SCOVERV CISCRIPTa0N status  % Powf A OTHEA STATUS OtSCDVE AY 1 inj 10 I e I si In I LAJ l n I 44 45 46 80 7 8 9 10 12 13 AMOUNT OF ACTIVITY LOCATION OF AELEASE R LE OF REL ASE

' LzJ IzJ l n i I n I 44 45 80 7 8 9 10 11 PERSONNEL EXPOSURES NUMBEA Tt PE DE SC AiPTON DE I 010101 (zj i NA 80 l

7 89 11 1a 13 PERSONNEL INJUAIES NUMBE R DI SCRIPT ON l

M 101 010 1 l n 80 7 89 11 12 OFFSnE CONSEQUENCES i

HI n gg 7 89 LOSS OR DAMAGE TO FACILITY T Y PE DE SCAtPT ON l

DE [,Zj Z l NA 80 7 89 10 PUBttCITY l

DE I NA 80 7 89 ADDITIONAL FACTORS b 2  ;

I Mln .

80 7 89 9102130530 771007 CF ADDCK 05000263 ^ ~~ "

g1 cF ,

l 80 7 t, .

Dean D Tilly , PHONE. 612/295-5151

• . NAME:

g  ; .F . ......,

h ) , g / n n. / A + J e r #'

MSPsce.gg L,e - *"

f.

n NORTHERN STATES POWER COMPANY MIN N E A PO LI S. M IN N E S OTA 9 8401

.q , ,

October 7, 1977 n T-~

v ,, . I IE77 k~ 'd5;% ' --

Mr J G Keppler, Director, Region III Office of Inspection and Enforcement U S Nuclear Regulatory Cocmission 799 Roosevelt Road Glen E113 m, IL 60137

Dear Mr Keppler:

MONTICELID NUCLEAR GENERATING PIANT Docket No. 263 License No. DPR-22 .

1 Failure of RHR Test Line Isolation Valve MD 2009 The Licensee Event Report for this occurrence is reproduced on the back of l this letter. Enclosed are 3 copies.  !

l Yours very truly, 6- l L 0 Mayer, PE i Manager of Nuclear Support Services l IDM/KiV/ak I

cc: Director, IE, USNRC (30) l Director, MIPC, USNRC (3)

G Charnoff MPCA - Attn: J W Ferman 0:T 1 -' 1977

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