ML20086S584

AO-S1-74-10:on 740802,one Spent Fuel Pit to Boron Recovery Sys Temporary Hose Line Connection Separated from Fitting, Spraying Primary Grade Pump House Interior.Caused by Inadequate Design of Clamping Arrangement

ML20086S584
Person / Time
Site:	Surry
Issue date:	08/21/1974
From:	Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
AO-S1-74-10, NUDOCS 8403020450
Download: ML20086S584 (6)

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' d..18u . k Mr. Norman C. Moseley, Director Serial No. 239 Directorate of Regulatory Operations 70W/JTBac1w United Statsa Atomic Energy Commission Region II - Suite 818 Docket No. 50-280 230 Peachtree Street, Northwest Licensa 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 Abcormal occurrence Report No. A0-SI-74-10.

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

Very truly yours, S. / .hdt$f C. H. Stallinas Vice President-Pover Supply and Production Operations Enclosures 40 copies of A0-81-74-10 cca Mr. K. R. Go11er, Assistant Director for Operating Reactors t

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ABNORMAL OCCURRENCE REPORT REPORT NO. A0-SI-74-10 UNPLANNED RELEASE OF LOW LEVEL RADI0 ACTIVE WATER TO JAMES RIVER AUGUST 12, 1974 DOCKET NO. 50-280 LICENSE NO. DPR-32 SURRY POWER STATION VIRGINIA ELECTRIC AND POWER COMPANY

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1. INTRODUCTION In accordance with Technical Specification 6.6.B.1 for Surry Power Station, Operating License No. DPR-32, this report describes an abnormal occurrence which was identified on August 2, 1974. The Directorate of Regulatory Operations, Region II, was notified on August 2, 1974.

The occurrence reported herein is classified as an abnormal occurrence pursuant to Technical Specification 1.0.1.3 which states that: "An abnorhal occurrence is defined as: Any uncontrolled or unplanned release of radioactivity from the site." The occurrence described herein resulted in a minor unplanned release of radioactive liquid effluent from the station which leaked into the ground around the primary grade water pump house and thereafter to the James River.

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SUMMARY

OF OCCURRENCE On August 2, 1974, Unit No. I was operating at 97 per cent reactor power and approximately 780 MWe generator output. Water was being transferred from the spent fuel pit directly to the boron recover'y system using a temporary hose line arrangement. At 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, during the transfer, one end of the temporary hose line connection separated from its fitting, spraying the primary grade (P.G.) pump house interior with low level radioactive water. The transfer a

process was secured with the majority of the spilled water. retained and I

collected within the P.G. pump house.. It is' estimated, however, that.a maximum of 150 gallons'of the contaminated water was discharged'through windows 'and t

under a door to the surrounding area. Part of the liquid spill then drained into the storm sewers and subsequently to the James River.

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Ill. ANALYSIS OF THE OCCURRENCE The transfer of water from the spent fuel pit to the boron recovery system was necessitated by the high water level in the spent fuel pit and the need to increase the boron concentration in anticipation of impending refueling operations.

To accomplish this transfer, a temporary hose line was installed from the discharge of the spent fuel pit purification pump, 1-FC-P-3A (located in the fuel building, 8' elevation) to the discharge of the boron evaporator feed pump, 1-BR-P'2A (located in the primary grade (P.G.) pump house, 27'6" elevation).

The temporary line was connected to check valve, 1-FC-45, downstream of 1-FC-P-3A by installing a flange / nipple arrangement in place of the check valve cap. The hose was secured to the nipple by hose clamps. A similar connection was made at : heck valve 1-BR-136, downstream of 1-BR-P-2A. Using the spent fuel pit parification pump as the transfer mode, the water was discharged through the temporary hose arrangement to the boron recovery tanks and subsequently to the "A" boron evaporator.

Analysis of the operation revealed that the design of the clamping arrangement utilized in the temporary hose connection was not suitable to withstand the discharge head pressure developed by the spent fuel pit purification pump. As a result, the hose slipped off the temporary fitting at check valve 1-BR-136.

Watcr from the spent fuel pit and the boron recovery tanks began spraying into the P.G. pump house. The spent fuel pit purification pump was immediately stopped and the water release terminated.

Although most of the low level radioactive water was collected within the P.C. pump house, a maximum of 150 gallons of this water was discharged by water spraying, through windows and~ leaking under the door, to the area outside the pump house.

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IV. CORRECTIVE ACTION TO PREVENT RECCURRENCE The immediate corrective action was to secure the spent fuel pit purification pump and close its suction valve, 1-FC-44. The boron recovery tank outlet valves were also shut. An operator donned a protective wet suit and isolated the temporary hose connection by closing 1-BR-137. The Health Physics Department was notified and a representative sample of water in the PG pump house was obtained for analysis.

The temporary hose fittings were removed, decontaminated, and sent to the station's maintenance shop for modification. Two beads of weld material were laid around the circumference of the nipple, with distance between beads of approximately two (2) inches. This modification will allow sufficient resistance against future slipping of the hose from the nipple of the temporary fitting.

V. ANALYSIS AND EVALUATION OF SAFETY IMPLICATION OF THE OCCURRENCE A maximum of 150 gallons of the low level radioactive water was discharged to the storm sewers and the surrounding area. Based on a representative sample taken from the primary grade pump house immediately following the occurrence, the total activity released in the 150 gallons was approximately 0.0332 curies (Tritium-0.0283 Ci; Xe-133-negligible; I-131 0.0003 Ci; Cs-137 0.0011 Ci; Co-58 0.00168 Ci; and several other isotopes of extremely low activity). A 5

dilution flow rate of the discharge water was assumed as 7.84 x 10 g,17, ,

per minute. It was also conservatively assumed that all 150 gallons of radioactive water was injected into the discharge canal' within one minute an no soil absorption occurred. Tritium had the highest activity level in the 150 gallons discharged and its activity prior to dilution was computed to

-2 be 5 x 10 C1/ml. When diluted, the Tritium activity level af ter one minute

-0 was computed to be 9.5 x 10 pCi/ml which is approximately 1/300 of.the limit s

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of 3 x 10~3 pC1/ml as set forth in Appendix B to 10 CFR 20. All other isotopes of lesser activity were within the 10 CFR 20 limits. Since soil absorption and time of flow were not considered, these calcula tions were most conservative and made on a worst case basis. Considering further dilution as a function of time, it can be concluded that these activity levels were insignificant and posed no problem from a public health viewpoint.

VI. CONCLUSIONS The licensee concludes that:

1. The unplanned release was the result of the separation of a temporary hose connection.

2. An insignificant amount of radioactivity was released to the environment and all concentration levels were well within 10 CFR 20 limits.

3. The occurrence described herein did not affect the safe operation of the station.

4. The occurrence described herein did not affect the health and safety of the general public.

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