ML19261F223

Abnormal Occurrence 50-289/74-22:on 741106,containment Isolation Valve CA-V2 Improperly Reassembled.Caused by Inadequate Procedural Guidance Re Valve Checks.Valve Reassembled W/New Gate Assembly & Personnel Counseled

ML19261F223
Person / Time
Site:	Three Mile Island
Issue date:	11/15/1974
From:	Arnold R METROPOLITAN EDISON CO.
To:
References
GQL-0485, GQL-485, NUDOCS 7910250647
Download: ML19261F223 (4)

Text

. .

9-

- e- -..- - -..v- -, . : ,. . . .- . . r . , i .e r.. n. 0 - ,o .- u.-

s. . ' ". w \ - *-Ae- r. - ~. n'u' i '~-

z.

_ , . g ., , , _ , . ,

8. . t . m. . . s - . .a COM T R O L NO - 11771 FILE: __

c . n_. . .

-- Me+u opo1". .an "r'.m" son Co. D n' ~ ~ C '- '.n. u' ! vn' i c n : C' D

~ ~-

L~; n ~".

.' .\' i o D '". I o~, ~: . -~-

Reading, ca. 1  !

19003

-. c -, 3, m__a ll-15-Th I 11-18-7h X t O ,..e , , ,- ~, e,,, c-..- v, , : , -.s n ,CC i uv v ccn  :..i n i

vac .e - . . .e , L, ,, . .Lrur-

-- X"Y 1 sig.ed I - _

_nr w _.

,. . . . . . . . c, v 4 u t.n.;d

,n. _ , L, T e.O C ,/ S F.sv

- ,. ., D O u,, k.  : ._ , ,i..':

v L r. . .-.ca .' - nu r i.s r u

CC{ l 1 l 50-269

__D ECRIT Ti'!. '- '

Ltr adv of Abnormal Occurrence l ENCLOSURES:

A0-50-289/Th-22 on ll-6-7h re i= proper reassedbly of contain=ent isolation valve CA-V2.....

pJj p#y 6 (R 2, D D m - - - --

o(@'1 e f Ul l h d M,i eit.a

.;.A.

r .i h,....:: Three Mile Island Unit I D0 c.v. . . .. . ~

F Ls.,.,..,. L a r~_, . . . . , , . . . ..ni , . . , , ,u, i DEL 11-20-74 _ _ .

te em T' :s ' '. : 1. . r., t. .:- s , ~7s ' r *..e. * .lt. _ r ."' s* .1 . C 'l

~*f*.'-

.. L s_, w . . ... }'

.. CC'en5 'e' 0 ' ^' ' .' 3 Y ' ' 0 .~. $ 5 ' 'll C C ,&

sn

Mr (e\

.m - i

- ., t e r, ,_e..i-6s a' ~1 (.,) 7~_itm . ' ' L' va-c i t : s1 t ;

' . ' . C C G W/ CG.i? D/ CCY:S 'UhCOpDS os r Ia . .:.\ t1b-} \v M.cc -..I e -sr ks.\,

7*. I-

• r

'. A v .'c.'1s

.\ t', .-- ~* b $:\1 b.Q l 6 3 .

b '. ; b ' b C 3 W/ CCp $

.'.s . ._. %,i

~1 n i i n. . . L u rv '('t. s

,6 v^t,T V v ,.e,-i s., . v'r.s.. os its

t. J V. ' w W e's V.'l C '.s p U s "ll Co;:a Wl Ccm

=

t . .ir * * .

i *.1 i t i . .- mv.m4 : c*..- -* 1. . 'v -i . r . . mem e e.m.

[~. =i; D T E " d = =_ ' .! ' = '.'- . C=_.'.~". .

_1 "v ,*J.

• T ., '

7 ; rs.

, .' y Q ,, . . . _ 7) _. .

tm

.  : : . .n-1_;:.

- . . ,s:n- <. .: , i.- g j n-- n. g (. ! , c.--

vn- -

. , t;e. s .: - .ni . .  : . s,-u r*r . v

,,. . s n. .,q- . c_ .' G : n " ' .

< t.. i o . ' ' '.-

v. .

.s: . , ;, ,'-. *rs;g (,vny : -sL_ ..w..,...:

v+. 4

.s . ca

^

l . .,, '. 3 t.'.' ,

'v:' ts- I C "' N

.s.

i l I. (. "l

s. -Q ' n . "- t..'.:_ .: .'s - .,_ i.

'. c 'v . .'_' _.- ] w: 1 t

p 1_ * .-'

^ -

-~m E r,r s. S: o r. '., a r s t s.c_gI a

. . - . C. '_

-: ~ ., ,- -

..m-,,e-i.e UV ii t. g L l ',...I i

_ , . . ,) ..

0:s

. . , ~ -

. q/ i n U. 4.l a,l.e.. p-I f, s g .,_ ) C h.- . . ..c .

m-s... ....-

. !,. } l . ,- . O 8

,,,,,c,,.

i s. .ae s'. s.,. V ,_ u

s n.:, "u n '.rg n e , , -" '

Uv t.,

(.' y . . ; .

.-. n,..--

. .i

,g r.

.c.s.'.p.1 ; ps .,.;9g - . g s./ a - -

t

. t . .a. . w.s q.-: .p g , 3,% ;.;....,-l

(, .g ?- ..: C - g i. t 1,

. : P..C. .~., g'sM.T.'. . . C H .:P D . 7. i

.- t.~,' I y g 'u m ..I .-.- . ./ .a, . .~~sn** "-

, O ,M :v s.',-'.v v .. *- . t - uA,, s'.

s C . { (j tt. t .i -T-

. .' .s '. .q ,

3 (. w -

Or*tc.

66 .es )i,..vq - ;- ^

o t:

i- :. U' m ' ' . ew.is ,* *s I T . * ( r '/ ,

.s--w'..t=^~:

,L 4 1, .. c u _ s_ ..,-.

'_q . i -.

p..

.. J . a tn n . . n,.J ., in.. i , s.--

t. L r it: ia :Lg -

i --.

-.b:...-n.

3 f,

._-I It, - u s t e ! s) .-a', ...,,L,.g...

.': _ .i

, . r ,

. .,-ne.%, e

,- , u -i p. . . r r.

. y s

,L...._ u - .: t .u' i . l L c S.v. t,)

. .a.sr 1

1 .

.,m i . u._ c .

1 t jJ c : . ., -- A _g 'f.2 2

. , , ~ , . .

-_7_ _:-3 .,.

o,

+ - r- p

'.i t- .:Cr. C ;._, ' ' .:' " Harrisburg,

- J_Pa j ' _.  ; .

. S j _ f rl' , 3. ',

i , ,

$ ,. .N ; 1; i C'in. *

' i - r .'., i - 'E .i .C , lt -

w1',C 5t'.. .

1 -. m,,,')!C. L ,,,

1 -

-, ' . , ,-~ ,. 1 .v.

h _ f . ) e. m. b h aha se _ w e as .-5 e d*s ..5. ' ~

• q g g g g' ss u . s ss ..

s. Ters n-20-7h -.:. .

g

y,go , .., 3 .py.

WN.7%d e _

G exto su sex rss METROPOLITAN EDISON COMPANY

. - - , . ~ . - - - ..

DZT OFFICE BOX 542 PEADING. PENNSYLVANI A 19603 TELEPHONE 215 - 929-2601 E ! 1 5 1974 GQL 0485 y .g w.

f . ' '- 'l , ..

N' .-

Director

/s D irectorate of Licensing

. [ '; Ui U.S. Atomic Energy Commission ~Q, ,7 Washington, D.C. 20545  :- i

Dear Sir:

~'

w Docket No. 50-289 .

Operating License DPR-50 In accordance with the Technical Specifications for our Three Mile Island Nuclear Station, Unit 1, we are reporting the following abnor- - - -

occurrence: '<1 t<V

'& a' (1) Report Number: A0 50-289/74-22 cc C -

(2a) Report Date: November 15, 1974

l. ~ ~ .

lini,

-J '

a. h , x m

g ,," i x,?' idf't fS*

(2b) Occurrence Date: November 6, 1974 (3) Facility: Three Mile Island Nuclear Station, Unit 1 DCC ' G 0 $SQ

\

Gl i

(4) Identification of Occurrence: CD [M

Title:

Improper Reassembly of Containment Isolation Valve CA-V2 Type: An abnormal occurrence as defined by the Technical Specifications, paragraphs 1.8d and 1.8e, in that the improper reassembly of Containment Isolation Valve CA-V2 caused an Engineered Safeguard feature to be incapable of performing its intended function and constituted an abnormal degradation of one of the several boundaries designed to contain the radioactive materials resulting from the fission process.

(5) Conditions Prior to Occurrence: The reactor was at steady state power, with major plant parameters as follows:

Power: Core: 100%

Elec.: 863 .W (Gross) \\

1177

. RC Flow: 138 x 106 lbs/hr RC Press.: 2155 psig RC Temp.: 579 F PRZR Level: 240 in PRZR Temp.: 650 F (6) Description of Occurrence:

During maintenance of Primary Sampling Containment Isolation Valve CA-V2 on November 6,1974, it was found that the valve's split wedge gate assembly was missing. An investigation cond.cted soon af ter this discovery revealed that the valve had been disassembled on June 18, 1974, for the purpose of replacing a leaking bonnet gas ket . This investigation further revealed that the maintenance was performed by maintenance contract personnel under a " Work Authorization" prepared and accomplished in accordance with procedures specified in the Startup and Test Plan which was in effect at that time. It appears that the valve gate assembly was not put back on the valve stem when the valve was reassembled, and without the gate assembly, the isolation valve could not perform its intended isolation function.

This condition went undetected for four months because the valve was kept in the open position during this period, and except for routine surveillance testing (which is not designed to detect the missing gate), no attempt was made to try to close it. It was not until the valve was disassembled for maintenance that the condition of a missing gate was discovered. Also, it should be noted that based on a previously run seat-to-disc leak-rate test , it has been determined that the gate was installed for the time period preceeding the June 18, 1974, maintenance work.

(7) Designation of Apparent Cause of the Occurrence:

Inadequate procedural guidance was the apparent cause of the occurrence in that the generic procedure used in conjunction with the Work Authorization referred to above addressed only valve-body to bonnet gasket replacement, and nothing in the procedure required personnel to check the valve internals prior to reassembly.

(8) Analysis of Occurrence:

CA-V2 is the primary air sampling containment isolation valve and is located outside the containment structure. There are three sample lines which feel into CA-V2, and all of these sample lines are equipped with an ' solation valve located inside the containment s t ruct ure . During tha period that CA-V2 was inoperable, these three isolation valves were operable and would have provided the necessary isolation had there been an actuation of the Engineered Safeguards (Actuation) System. It can be concluded from this that the inability o_f,fContainment Isolation Valve CA-V2 g

perform its Engineered Safeguards function did not constitute a threat to either the health or safety of the public.

(9) Corrective Actions:

As described above, an investigation was begun soon after the condition was discovered. Fue ar immediate actions consisted of reassembling the isolation valve with a new gate assembly in accordance with an approved maintenance procedure and then leak-rate testing the valve in accordance with 10 CFR 50, Appendix J, and the Technical Specifications. The leakage rate was found to be icos than 1 cc/ min, which is well below the 10 CFR 50, Appendix J, and Technical Specification limits.

At a meeting held af ter the condition was reported, the Plant Operations Review Committee (PORC) reviewed and approved the above actions, and also recommended to the Station Superintendent that:

(1) sub-contractor supervisory personnel and Met-Ed maintenance supervisory personnel be counseled by the Supervisor of Maintenance on good maintenance practices, and (2) the generic procedure to replace valve body to bonnet gaskets be revised as follows to ensure personnel check valve internals prior to reassembly:

a. require an evaluation be made to determine whether or not, based on the condition of the valve internals, a seat-to-disc leak-rate test should be conducted as a post-maintenance check, and

b. require verification of the presence and correct orientation of all valve internals prior to valve reassembly.

The Station Superintendent concurred with these recommendations, item 1 above has been completed, and appropriate actions have been taken to ensure revision of the subject generic procedure.

(10) Failure Data:

Not applicable.

Sincerely, f, i R. C . rnold RCA/JFV/cas Vice President File: 20.1.1/7.7.3.5.1 cc: Directorate of Regulatory Operations - Region 1 U.S. Atomic Energy Commission 631 Park Avenue King of Prussia, PA 19406 kh