ML20087D708

AO-S1-74-09:on 740606,discovered Quantity of Fuel in Emergency Diesel General 1 Fuel Oil Tank Below Tech Spec Limits.Caused by Inoperabiliry of Both Level Switches in Auxiliary Tank.Switches Repaired & Returned to Svc

ML20087D708
Person / Time
Site:	Surry
Issue date:	07/11/1974
From:	Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
AO-S1-74-09, AO-S1-74-9, NUDOCS 8403130500
Download: ML20087D708 (7)

Text

. ..,

,'Q--). p\J

, \'M db x //n^i VinotNIA Er.a rRIC AND Powna COMi*AW '9e rec 5vf D 'r',

Htcaruoxn.V notwrA 2026: " g gg,.

m c.s. nt;:: c::n July 11, 1974 Ei~.Z"i/ ,b e+ Lia t .a /s f," -- ..

\

Mr. Norman C. Moseley, Director Serial No. 190 Directorate of Regulatory Operations P0&M/JTB:clw United States Atomic Energy Commission Region II - Suite 818 Docket No. 50-280

, 230 Peachtree Street, Northwest License No. DPR-32 Atlanta, Georgia 30303

Dear Mr. Moseley:

Pursuant to Surry Power Station Technical Specification 6.6.B.1, the Virginia Electric and Power Company hereby submits forty (40) copies of Abnormal Occurrence Report No. A0-SI-74-09.

The substance of this report has been reviewed by the Station Nuclear Safety and' Operating Committee and will be placed on the agenda for the next meeting of the System Nuclear Safety and Operating Committee.

Vcry trul;.ycurs,

. /k. Wb' f!'

C. M. Stallings Vice President-Power Supply and Production Operations Enclosures 40 copies of A0-S1-74-09 .

cc: Mr. K. R. Goller, Assistant Director for Operating Reactors I

(, ,)

V 'U h ((V s

- COPY SENT REGION p3!dNEg .

6720 )

t

. a

l o o- l I

1 ABNORMAL' OCCURRENCE REPORT.

REPORT NO. A0-S1-74-09 VIOLATION OF LIMITING CONDITION OF OPERATION EMERGENCY DIESEL GENERATOR FUEL OIL SUPPLY I

i

' JUNE 12, 1974 b

'l DOCKET NO. 50-280 LICENSE NO. DPR-32 4

l SURRY POWER STATION 4

VIRGINIA ELECTRIC AND POWER COMPANY 9-i t

v

~

+ <

s n

7 1

- 3: .; ;

4

.,' 21 ..

~

, - gj

'.~._ .:- _ _ _ .. a._,_ , ,- , ,'? t ' ,

y

.e

• O- O

1. " INTRODUCTION In accordance with Technical Specification 6.6.B.1 for Surry Power Station, Operating License Number DPR-32, this report describes an abnormal occurrence which was identified on June 6, 1974. The Directorate of Regulatory Opetations, Region II, was notified on June 6, 1974.

The occurrence described herein is classified as an abnormal occurrence pursuant to Technical Specification 1.0.I.2 which states that: "An abnormal occurrence is defined as: Any unit condition that results in violation of a limiting condition for operation as established in these Technical Specifications."

, The occurrence described herein resulted in the violation of Technical Specification 3.16. A.7 which requires that a minimum of 290 gallons of fuel oil be maintained in the emergency diesel generator i

. day tanka. The level of No. I day tank was maintained at approximately 190 gall'ons for a short periodlof time.

i

11. SUl@!ARY OF OCCURRENCE On June 6, 1974, at approximately 0135 hours0.00156 days <br />0.0375 hours <br />2.232143e-4 weeks <br />5.13675e-5 months <br />, with the~ unit at-100 per cent of rated power, it was discovered that the quantity of fuel in the No. 1 emergency diesel

generator f uel oil tanks was below

,that specified in Technical Specification.3.16.A.1. 'The combined capacity of the auxiliary _ tank and the base tank,1 collectively referred to as the day' tank,;was less than-190 gallons, as compared with the technical. specification limit of 293 gallons.

.The low level in the base tank was discovered during an operability ~

check when No. 3' diesel generator was removed from service for.

._ ,._ ,_ _,. ._c. -

m

{.f .

o o mainte..ance. 'There was no fuel oil in the auxiliary tank. The operator was alerted by the annunciator " Emergency Generator 1 Trouble" alarm when the base tank level reached the 190 gallon alarm setpoint. The reduction in fuel inventory was caused by the failure of both fuel oil pumps to start automatically on low level to maintain sufficient oil inventory in the auxiliary tank. The failure of the pumps to start was caused by inoperability of the level switches in the auxiliary tank. The level control switches are models A103 and A153-K-TDM manufactured by the Magnetrol Cor-poration.

Ill. ANALYSIS OF OCCURRENCE The diesel generator fuel oil supply system is schematically shown in the attached figure. The system consists of a 550 gallon capaciry base tank un the diesel generatur, two (2) fuel oil transfec pumps for each diesel generator, uan auxiliary tank of 550 gallon capacity, two (2) fuel oil pumps, two (2) underground tanks (20,000 gallons each) and a 210,000 gallon aboveground storage tank. The aboveground. storage tank and the underground tanks serve the three

^ ~

(3) diesel generators. Each of the diesel generators is equipped with redundant flow paths containing the remainder of the listed equipment.

The base tanks are automatically filled by the fuel oil transfer pumps on. low level *in the base' tanks and'the diesel is operating-and' the generator is excited. The auxiliary tanks are supplied from the underground storage tanks by fuel ' oil pumps which are actuated

~

9 9

n -e m '

2

sf .'

.. .- 0 O by level switches on the auxiliary tank. There are two (2) level switches on the auxiliary tank, each of which starts one (1) of the two (2) pumps and opens the solenoid valves at a preset level.

The occurrence reported herein was caused by the inoperability of both level switches in the auxiliary tank. Investigation of the occurrence revealed that only one (1) of the two (2) level switches were in place. The in place switch had apparently been rendered inoperable as a result of a faulty spring causing the switch to hang up. The other switch had been removed from service for approximately two (2) weeks to repair a faulty mercoid switch. Since each of the level switches separately actuate one (1) fuel oil pump, both of the pumps were rendered inoperable in the automatic mode.

IV. CORRECTIVE ACTION TO PREVENT RECURRENCE The imma, Hare corrocriva actinn wa= to repair both dafectiva

switches and return them to service. In addition, a low level 4

alaru will be added to the auxiliary. tank to indicate when a J

l problem occurs in the fuel transfer from the underground tank to the auxiliary tank.

Station personnel have been cautioned to assure that when equipment is removed from service for maintenance the Shift Super-visor is advised of operability status.

.V. ANALYSIS AND EVALUATION OF SAFETY IMPLICATIONS OF'THE OCCURRENCE The emergency diesel generators provide;an independent, '

automatically starting power supply to vital. auxiliaries if a normal source of power is'not'available.

e i

o o Diesel genera' tor No'. I would have operated a short time on the available day tank fuel supply and operator action of placing the fuel oil transfer pumps in the manual mode would have ensured a

, fuel oil supply to the diesel generator.

l

! Emergency diesel generator No. 3 was operable, as proven by an '

operability check at the time, and could.have assumed the load if it had been required.

~

VI. CONCLUSIONS The licensee concludes that:

i j 1. The occurrence described herein was-caused by the in-i operability of the auxiliary fuel oil tank level control i

switches.

2. The occurrence reported herein did not affect the safe nnararinn nr rna cratinn-

?,

3. The occurrence described herein did not adversely affect the health or safety of the general public.

j 1

(

• 1 1

r 9

-4 . , -

, , _.___ __ _ _ _ w

t E31ERGENGY DIESEL Cell:'RATOR FUEL OIL SYSTE!!

ABOVE GROUND TANK 210,000 GALLOM g FUEL 01L PU!!PS SOLENOID VALVES r r-- 1 ,

o

(

,l' I' }/. - -

O

'I l

I C

O ALA101

$ (CONTROL l

a f 'X I R00>1)

I IlI 8 l

d i I g g FUEL OIL TRANSFER PtrlPS t l

- I e I l s , n _.

t t___1___ - l

_______ 3 __2 UNDEl: GROUND TANKS AUXILIARY TANK BASE ~ TANK (20,000 CA1,EACII) (5'20 CAL) (550 GAL)

Cr

'.' COMMON < y FOR EACl!

, DIESEL GENE 4\ TOR k

? e e