ML20087L629

Ao:On 730708,high Level Alarm on Facade Sump Received in Main Control Room.Caused by Small But Steady Flow Into Sump from Unknown Source.Retransfer of Borated Water from Refueling Water Storage Tank Instigated

ML20087L629
Person / Time
Site:	Point Beach
Issue date:	07/16/1973
From:	Burstein S WISCONSIN ELECTRIC POWER CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8403270309
Download: ML20087L629 (4)

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July 16, 1973 Mr. John F. O' Leary, Director Directorate of Licensing U. S. Atomic Energy Commission Washington, D. C. 20545

Dear Mr. O' Leary:

DOCKET NOS 50-266 AND 50-301 POINT B CH-NU EAR PLANT UNSCHEDULED RELEASE OF RADIOACTIVITY AND VIOLATION OF A LIMITING CONDITION FOR OPERATION This is to report the details of an abnormal occurrence at Point Beach Nuclear Plant as defined by Sections 15.1.a.B and 15.1.a.C of the Technical Specifications. This written report is in accordance with Section 15.6.6.A.2 of the Technical Speci-fications and follows a telephone report made on the incident to Mr. K. Baker of Region III Regulatory Operations on July 8, 1973, as required by Section 15.6.6.A.1 of the Technical Specif.ications.

At 0415 hours0.0048 days <br />0.115 hours <br />6.861772e-4 weeks <br />1.579075e-4 months <br /> on July 8, 1973, a high level alarm on the Unit 1 facade sump was received in the main control room. It was assumed at that time that the alarm was the result of normal ground-water drain accumulation and an operator was dispatched to pump the sump to the retention pond via the sewage plant sump.

Approximately five minutes after a facade sump pump was started, the control room operator noted that the high level alarm had not yet cleared and contacted the auxiliary operator for an explanation. It was found that the sump pump was incapable of emptying the sump because of a small but steady flow into the sump from an unknown source.

Two possibly related plant operations were in progress at i that time. The water treatment plant was making up water to the I "B" reactor makeup water tank and the Unit 1 refueling water stor-age tank had recently been placed in the recirculating mode in preparation for the taking of a weekly sample. An investigation of these two operations quickly determined that the Unit 2 refuel-ing water storage tank level was down to 92% (267,000 gallons) and l the Unit 1 refueling water storage tank indicated 100%. The Unit 1 refueling water storage tank was found to be overflowing. The re-circulating of the tank was immediately terminated and.the facade sump pump was stopped. y .

f p, 3t 8403270309 730716 (' d g DR ADOCK 05000266 9p COPY SENT REGION 7 58*7

-.-.- a O O Mr. John F. O' Leary July 16, 1973 Retransfer of borated water from the Unit 1 refueling water storage tank to the Unit 2 refueling water storage tank was instigated. The Duty Shift Supervisor and Duty and Call Superintendent conferred on the desirability of shutting down the Unit 2 reactor during this period when its refueling water storage tank was temporarily below its Technical Specifications requirement of 275,000 (95% tank level) , but determined that the problem would be corrected before an orderly shutdown of the unit could be accomplished. The Technical Specification quantity of 275,000 gallons was re-established by 0640 hours0.00741 days <br />0.178 hours <br />0.00106 weeks <br />2.4352e-4 months <br />. ,

The quantity of water pumped to the retention pond from the Unit 1 facade sump was later estimated to be 250 gallons.

An analysis showed the radioactivity concentration of this water, before dilution, to be 5.33 x 10-3 pc/ml for a total discharge of 5043.8 pc. Following dilution with an estimated 18,000 gallons of wateringhesewageplantsump,thecalculatedactivitywas 7.4 x 10- pc/ml, which is approximately 8% of the permitted MPC for discharges to a restricted area.

An isotopic analysis taken from samples drawn at the dis-charge to the retention pond produced the following table:

Concentration in Concentration Total Retention Pond %MPC Before Dilution Activity After Dilution For Restricted Area Isotope uc/ml  % pc/ml In Retention Pond 144 Ce 1.02 x 10-4 1.912 1.417 x 10-6 0.472 137 Cs 4.68 x 10-5 0.867 6.500 x 10-7 0.163 134Cs 8.49 x 10-5 1.599 1.179 x 10-6 0.393 60Co 4.99 x 10-3 93.629 6.930 x 10-5 6.930 58Co 3.27 x 10-5 0.619 4.540 x 10-7 0.0135 54Mn 7.50 x 10-6 0.019 1.040 x 10-7 0.0260 95zr 2.16 x 10-5 0.419 3.000 x 10-7 0.0150 95Nb 4.01 x 10-5 0.756 5.570 x 10-7 0.0186 103Ru 2.52 x 10-7 0.005 3.500 x 10-9 0.0017 TOTALS 5.33 x 10-3 99.825 7.3,96 x 10-5 8.0328 3H 4.34 x 10-3 100.000 6.028 m 20-5 0.0603

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i Mr. John F. O' Leary July 16, 1973 J

Initial samples taken at the discharge of the retention j pond produced non-detectable levels.

4 It is concluded that the unscheduled discharge from the Unit 1 facade sump to the retention pond and thence to the reten-4 tion pond discharge are well below unrestricted area MPC limits.

To further substantiate this statement, further samples will be taken at the discharge of the pond at 15 and 30 days (30 days being the pond's calculated holdup time) . Should these produce t levels of any significance, we will inform you promptly of the levels measured.

The 3% deficiency in level in the Unit 2 refueling water

, storage tank is approximately equal to 8,000 gallons. Calcula-tions show that at the Technical Specification value of 275,000 gallons at 2,000 ppm boron, 4,580 pounds of boron are contained i

in the refueling water storage tank. The concentration of boron following the level reduction to 92% was 2,254 ppm boron; 267,000 i

gallons of 2,254 ppm borated water contains approximately 5,000 t'

pounds of boron. Accordingly, the ability of the refueling water storage tank to borate the reactor coolant system to a completely j shutdown condition was not compromised. In' addition, had the safety j injection pumps been called upon to take their full flow suction from the refueling water storage tank, the blender system would' have been capable of making up the 8,000 gallon deficit before the low-low level setpoint of the refueling water storage tank was reached.

To prevent a recurrence.of this incident, the following actions have been taken:

The operating procedure dealin transfers will be rewritten and'g with liquid expanded.

The Unit 1 facade sump pump has been lined up to the waste holdup tank. The pump will normally be left in the "off" position. Thus,.a discharge to the retention pond will requ. ire a conscious effort- to change a- valve lineup arx1 start a pump manually. The Unit 2 facade pump will also be normally left in the "off" position. As soon as modification to further reduce local ground-water entering the Unit 2 facade is completed, this sump will also be lined up to the waste holdup tank as a normal lineup.

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.___Q 0 0 Mr. John F. O' Leary July 16, 1973 Finally, disciplinary action for those per-sonnel who caused the incidents has been taken.

Very truly yours, Sol Burstein Senio Vice President cc: Mr. Boyce H. Grier, Regional Director Directorate of Regulatory Operations, Region III 4

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