ML18139A357

Forwards Response to IE Bulletin 80-05 Re Vacuum Conditions Resulting in Damage to Holdup Tanks.Two Potential Problem Areas Involving Boron Evaporator Bottoms Tank & Boric Acid Storage Tanks Identified

ML18139A357
Person / Time
Site:	Surry, North Anna
Issue date:	06/09/1980
From:	Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
IEB-80-05, IEB-80-5, NUDOCS 8006240238
Download: ML18139A357 (3)

Text

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e VIRGINIA ELECTRIC AND PowER COMPANY RICHMOND,VIBOINXA 23261 r.OJUNl2 June 9, 1980 Mr. James P. O'Reilly, Director Serial No. 223/031080 Office of Inspection and Enforcement NO/RMT:ms U. S. Nuclear Regulatory Commission Docket N,Ps.50-280----~

Region II * * * ~

101 Marietta Street, Suite 3100 50-338 Atlanta, Georgia 30303 50-339 License Nos. DPR-32 DPR-37 NPF-4 NPF-7 IE BULLETIN 80-05

Dear Mr. O'Reilly:

This is in response to IE Bulletin 80-05, "Vacuum Condition Resulting in Damage to Chemical Volume Control System (CVCS) Holdup Tanks". Our responses for Surry Power Station Unit Nos. 1 and 2 and North Anna Power Station Unit Nos. 1 and 2 are attached.

Very truly yours,

~~

,~ ~- Sylvia Manager-Nuclear Operations and Maintenance Attachment cc: Director, NRC Office of Inspection and Enforcement Washington, D. C. 20555

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RESPONSE TO IE BULLETIN NO. 80-05 NORTH ANNA POWER STATION UNITS 1 A.t'D) 2 Page 1 Pursuant to IE Bulletin No. 80-05 "Vacuum Condition Resulting in Damage to Chemical Volume Control System (CVCS) Holdup Tanks (sometimes called "Clean Waste Receiver Tanks")", dated March 10, 1980, a review of the Reactor Coolant, Boron Recovery, Chemical Volume Control, Liquid Waste, and Vent_ and Drain Systems has been performed to assure that adequate measures have been taken to protect low pressure or holdup tanks tha.t could be valved to contain primary system water or could receive primary system water due to overflow against vacuum conditions. Two potential problem areas were identified, the Boron Evaporator Bottoms Tank and the Boric Acid Storage Tanks. The corrective actions that will be taken are described in the following review results.

I. Chemical Volume Control System A. Volume Control Tanks (l-CH-TK-2 and 2-CH-TK-2)

The Volume Control Tank pressure and temperature are monitor-ed with indication given in the Main Control Room. Alarm is given in the Main Control Room for high and low pressure conditions. The tanks are provided with a remote operated solenoid valve backed up by a pressure control valve which ensures that the pressure does not fall below minimum operat-ing pressure during degassing to the Waste Disposal System.

The tanks are normally ma~ntained between 20 to 50% indicated level with a H blanket maintained between 15 and 60 psig. A pressure contro2i valve automatically opens and supplies H to 2

prevent the tank from falling below minimum operating pres-sure. Suction from the tank is isolated at 5% indicated level .. Drawing a vacuum in the tank is precluded by automatic actions. The Volume Control Tanks normally contain filtered demineralized primary system water. The Volume Control Tanks are located in the Auxiliary* Building.

B. Boric Acid Storage Tanks (1-CH-TK-lA, 1-CH-TK-lB, and 1-CH-TK-lC)

The Boric Acid Storage Tanks are vented to the Gaseous Waste System. Since the vents can be manually closed, the vent iso-lation valves will be locked open and administratively control-led within 30 days of this response. The Boric Acid Storage Tank normally contains highly borated, very low activity water .

. The Boric Acid Storage Tanks receive water from either the

• Boric Acid System Evaporator Bottoms Tank or the Boric Acid Batch Tank. The Boric Acid Storage Tanks are located in the Auxiliary Building.

Attachment

,f at the grade level south of the Fuel Building. Natural circu-lation heaters are provided to prevent freezing of the tanks.

Steam for the heaters is provided from the primary plant

• Page 3

• auxiliary steam system. The tanks normally receive water from the Boron Recovery Test Tanks after purity has been establish-ed or, when required, demineralized water* from the flash eva-

. porator.

Ill. Liq~id Waste System A. High Level Waste Drain Tanks (1-LW-TK-2A and

• 1-LW-TK-2B)

The High Level Waste Drain Tanks a:re vented to the Low Level Waste Drain Tanks. The* vent line has one isolation valve which is administratively controlled and is locked in the open position. The Low Level Liquid Waste Tanks are vented to atmosphere via a non-isolable vent. The High Level Waste Tanks are also vented to the process vent blower suction, thus continually purging any liberated hydrogen or radioactive gasses. The tanks normally contain a mixture of contaminated water from various sources. The tanks are located in t4e Auxiliary Building.

B. Low Level Waste Drain Tanks (1-LW~TK-3A and 1-LW-TK-3B)

The Low Level Waste Tanks are vented to atmosphere via a non-isolable vent. The tanks are also vented to the process vent blower suction, thus continually purging any liberated radio-active gases. The tanks are located in the Auxiliary Building.

IV. Vent and Drain System I

A. Primary Drain Transfer Tanks (l-DG-TK-1 and 2-DG~TK-1)

The Primary Drain Transfer Tanks are designed for full vacuum conditions. The tanks normally contain primary system leakage.

The tanks are located in Unit 1 and Unit 2 containment build-ing.

v. Reactor Coolant System A. Pressurizer.Relief Tanks (l-RC-TK-2 and 2-RC-TK-2)

The Pressurizer Relief Tanks and rupture discs holders are designed for full vacuum. The tanks normally contain relieved primary system water in a predominantly nitrogen atmosphere.

The ~anks are lo~ated in Untt land Unit 2.containment build-ings.

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