IR 05000133/1973001

Inquiry Rept 50-0133/73-01Q:on 730126,concentrated Liquid Radwaste Storage Tank 2 Overflowed Due to Partially Open Inlet Valve.Caused by Plugged Sump Drain in Tank Vault, Resulting in Leakage Ground Instrument Line Penetrations

ML20148T128
Person / Time
Site:	Humboldt Bay
Issue date:	02/02/1973
From:	Andrea Johnson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
50-133-73-01Q, 50-133-73-1Q, NUDOCS 8102180388
Download: ML20148T128 (1)

Text

' ' ' ~

+

-

, ,7

'

,

1

'

.j,. l-

^ UNITcD ril ATcS.

, A #' %%, L ATOMIC ENERGY COMMISSION E l DIFtECTOR ATE Or HEGut. A 4 opY OPER ATIONS

) *

HUGinte V .

,

, / ,

^ 2111.B ANCROFT WAY DCR KELEY. c ALWOHNI A 94704 gm,,, , , , , ,

,

k ;{p~fhp i i .m....

R0fInqu'iry Report No'.i050-0133/73-01Q Pacific Gas &. Electric Compan Humboldt: Bay Unit No. 3L License No..~DPR-7l BWR,;240.Hwt UNPLANNED RELEASE OF RADIOACTIVE LIQUID' EFFLUENT

Prepardd by:. yv a M d / 72

,j[.m.A.'D. Johnson,ReactorInc,pector

.

Date

' Date and Manner AEC was Informed A' representative of Pacific Gas and Electric Company notified

' D.' Johnson by telephone on January 26, 197 Description of Particular Event or Circumt.tance  ?

!The No. 2 concentrated radioactive liquid waste storage tank overflowed'

.

"

as a . result of . the . inlet valve being partially open. Apparently the

' sump drain in the tank vault was plo;;ged, and as a result, the solution ,

rose to a level of approximately 2 font and began to leak through the

. caulked annulus around one of the inntrument line penetrations.- It then flowed :to an outside sump which drained into the outfall cana This sump can also be valved to drain to the radwaste building ~ sum From the maximum time that the Icakane could have occurred and the maximum estimated Icakage rate,.the licensee estimated that a maximum quantity of 20 gallons had been released over a period of approximately six hours. The concentr.ytion of radioactivity in the liquid was measured to be 3.5 x'10 uC/ml. The total quantity of activity released was therefore estimated to have been approximately 3 mci (an amount

approximately equal to that contained in a routine laundry waste tank ' discharge) ~. Action by Licensee

-

The inlet valve to the storage tank ens fully closed. The licennce in

.l investigating ~the cause of the plugging in the vault drain to the radwaste j

,

building' sump'to determine the necennary corrective action to preclude l

.a recurrence. The licensec does not plan to submit a written report to

~

i

'the Directorate of Licensing since the' event does not fall within the l type.of. occurrences required to be reported to the AE The~1icensee plans to rerort the event to the State of California pursuant to the company's agreement with the State of California North Coastal Regional' Water Control Boar + poNra8 P00R BRIBIRM

s..-

• 1 j

a 4  ; ,

'

"

UNITED ST ATES '

i."

"

& M% ATOMIC ENERGY COMMISSION penECTOR ATE Ofr REGULATORY OPEH ATlONS

[ -) ;

HEGION V

, ,, ,/ ,

? -- 2111 B ANCROFT WAY

,

-)[ sERKELEY, C ALIFoRNI A 94704 ,,,n,,,,,,,,,,....,

.......

-'" j - DEC 6 1972 i .

l DIRECTORATE OF REGULATOP.Y OPERATIONS BULLETIN 72-3

!

Pacific Gas and Electric Company Docket No. 050-0133 77 Beale Street'

'

'

' ; San Francisco, California 94106 s

Attention: Mr. Frederick T. Searls ,

Vice President and General Counsel Gentlemen:

- We recently received information relating to the malfunction of electric

' type valve operators at two reactors. The valve operators were identified as Limitorque Models SMB-00 and SMB-000 which are used extensively in safety related systems at a number of PWR and BWR reactor facilitie Subsequent investigation identified a specific production group of these modeln which' vere manufactured between 1969 and mid-1971. The specific deficiencies are described as follows:

N Plant A Testing of valves and valve or.rators used in safety related systems at thin facility disclosed ten valves that failed to close following a " valve full open operation" test. The cause of failure was attributed to malfunction of the valve operator torq2e switch due to a lack of proper clearance between the moving parts o? the torque switch unit and the inability of the

" torque switch torsion spring" to return the electrical contacts to a closed position following operation of the valve. The weak torsion spring is considered a common mede of failure. Approximately 150 valves ranging up to eight inches in afee were equipped with valve operators having the faulty switche .

Plant B During a reactor starte , the inboard steam supply valve of the reactor core isolatien coolant (RCIC) system failed in the open position. Several attempts were made unsu cessfully to close the valv The failure was

,

--

attributed to an interp.1 torsion spring in the valve operator torque switch

. which normally resets the electrical contacts. The valve operator in .

question is similar to the units which failed at Plant '

Two additional facilities have recently experienced similar failures since those repopted at plants A and s4 i

ll Z -

'

.E4 E 156 966:2_

..

.

\

.

- - - _ _ _ _ _ _ - -

_

4 4

,

.

,(  ; . .

,

. ~; . '. '

'

-

-

' DEC 6 1912'

'

Pacific Gas and Electric C .

a

,

It,is requested.that you determine whether valve operators of the described make, model and vintage are installed or scheduled to be installed in your facilit If your findings show that valves installed or scheduled to be installed are equipped with the described valve operators,.please inform this office within thirty days,'in writing,.of the number of. valves equipped with the valve operators, the systems in which the subject valves are installed

>

.- ., - or scheduled to be installed, a description of corrective actions taken or

' . . . planned, and the scheduled completion date of your corrective action Should you have any question concerning this matter we will be pleased to

- discuss them with yo .

!

Sincerely,

• - "'

.

R. W. Smith

' Director

-

n

>

cc: Warren Raymond, Humboldt Bay Nuclear Power Station

,

'

bec: R0 Files .

'

[DR Central Files ,

PDR t

f

.

.

V .

'

o d

e

$

0

$

.

. 9 0 3 g6 %.-,

.

A "