ML19270E902

LER 78-055/03L-0 on 781202:during Control Rod Pattern Change & Scram Test,Control Rod Drives 46-39 & 38-39 Could Not Be Scrammed from Reactor Protection Sys Test & Monitor Panel C916,caused by Scram Pilot Valves Not Bleeding Down

ML19270E902
Person / Time
Site:	Pilgrim
Issue date:	12/27/1978
From:	Mathis C BOSTON EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19270E899	List: ML19270E898 ML19270E902
References
LER-78-055-03L, LER-78-55-3L, NUDOCS 7901030117
Download: ML19270E902 (2)

Text

. , . . . .

,., , i il coNTnOL oLOcx: l l l l l l l (PLE ASE PRINT Of t TYPE ALL HEOUlHED INFOrtMAllON)

' o@ .

E 8'l'Ml 9

ALICE.t45t l P lE COOL P l s i I4l l@l0 lo lo lo 10101010 15 LILLN',L NUMut H lo lo lo l@l W 41 11 2u 11 I l l l@l LICLNSL T YPE JD I

b1 t a l Wi l@ ,s l

NT U E 4 E' Z Lij@l0 I 5 lo l- 1012 19 l3l@[il210l2l7 la I@l i l 2 l flEPOHT 00 Le t Dott.LT P u% E H US ti> LVLNT DATL 14 lb 2 l 7DAIL l 7 l 800l@ -

EVENT OEScHIPTION AND PHOD ADLE CONSEQUENCES h y lOn Decenber 2, 1978, durfng control rod pattern change and scram testing of CRDs, control l :t g l rod drives 46-39 and 38-39 could not be scrammed from Reactor Protection System Test l [

g gand Monitoring Panel C916 Therefore, the requirements of T.S. 3;3.2.c could not be g g g satisfied. The CRDs were inserted and isolated for investigation and repair. The g f g g possible consequences were minimized by the insertion of the control rods, g f EI l Tirl i J 80 ,'

8 9 ,

SYST E M CAUSE CAUSE COMP. VA VE i' CODE CODE SUDCODE COMPONENT CODE SUDCODE SUBCODE II E 8 IRlB @ l El@ l B l@ l Vl Al Ll V[ E l X l@ {J@ l El @

9 10 11 12 13 lu 1 51 20 l

(

EVENT YE AR SE QUE NTI AL ftEPOHT NO.

OCCURRFNCE CoDL ftEPORT 1YPE ft E vtSION N O.

j LERrR O go;<Ol, 17 1 81 2, n 1-l n

1015 l 5 l u . :o l-l n

lol3l u n l tl 30 l_l 3,

[0 j n

^Ms"!Ws' ,J2&'u. ";'NITT .l,

's'#0 '#C#ss E "#f41 5'an?M' noUa5 ufMf2!"4n l33_

A J@l^ J4 l@ l zl@

Jb LzJ@

Ou LI J'

I I 40 I l_J 44

@ In18 42 Inl@

43 lAl611101@-

44 47 CAUSE DESCRIPTION AND CORATCTIVE ACTIONS h lf g l Investigation by I&C found the Scrar Pilot Valves not to be biceding down. Each CRD has l i

!I p ltwo pilots which were removed as an assembly and replaced from stock. The CRDs were j gthen scram tested successfully by operations. l EI I EI8 9 80 I

STA S *.POWE R OTHER STATUS 15COV iY DISCOVE RY DESCRIPTION I E lXl@ l0l5l0l@l N.A. 4 B l@l Routine Surveillance Test l ACTIVIT Y CO TENT f nEEE ASED OF RE LE ASE AMOUNT oF ACTIVITY LOCATION OF RE LE ASE  ?

N.A. N.A.

{W 8 P

@ l Zl@l 10 11 44 l' l 45 80 l

PERSONNEL EXPOSURES NUM(IER TYPE DESCRIPTION E*lololol@lzl@l N.A.

l PERsO~Nd'IN,u',fas l

NUYtiER DESCRIPT l t

{ 0l0l0[@l C 9 11 11 N.A.

80 l

g, EOM OF on DAMAC.E TO F ACILITY g TYPE DE SClllP110N 5 E Izl@l B 3 10 N.A.

B0 I ,

luoi n Puntic'TY lasCniPriON 7.901030(( nne<>sc oNoy .

E LNj _

l N.A. l l llllllllllj; ,

8 U lu 68 69 3W b '

Charles J. Mathis 617-746-7900 o l

P,0STON EDISON C0FfPANY

.,' PILCRIM NUCLEAR POWER STATION

.' DOCKET No. 50-293 Attachment to LER 78-055/03L-0 on December 2,1978, control rod drives 46-39 and 38-39 could not be scrammed from Reactor Protection System Test and Monitoring Panel C916 Investigation by I&C found the Scram Pilot Valves not to be bleeding down.

Each CRD has two pilots which were removed as an assembly and replaced from stock. The CRDs were then scram tested successfully by operations.

On December 4,1978, the assemblies were dismantled to locate the exact cause.

Within each assembly one of the pilots was found to have the nylon spring loaded ,

seat of the core assembly to be broken off and imbedded in the exhaust port preventing any bleed-off of air pressure through it. One of the bad pilots has been sent to the General Electric Company for examination while the other remains on site.

An evaluation of scram times for the past 16 week cycle was conducted in ac-cordance with T.S. 4.3.C.2 This evaluation disclosed that, since Saptember 15, 1978, 144 of the 145 control rod drives had had scram times verified to be within the requirements of T.S. 3.3.2.C.

To prevent future recurrence, a program will be established to repince all pilot heads and buna-N parts such as the diaphragas and body passage gaskets.

This program will commence with the next cutage (scheduled or unscheduled) as a non-critical path item. Henceforth, these parts will be replaced on a 5 year basis.

e