ML19323H279

Responds to IE Bulletin 80-05 Re Vacuum Condition Resulting in Damage to Chemical Vol Control Sys Holdup Tanks.Tank Damage Due to Vacuum Conditions Precluded by Design Provisions or Suitable Vent Connections

ML19323H279
Person / Time
Site:	Wolf Creek, Callaway, Sterling
Issue date:	06/06/1980
From:	Petrick N STANDARDIZED NUCLEAR UNIT POWER PLANT SYSTEM
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-80-05, IEB-80-5, SLNRC-80-27, NUDOCS 8006120312
Download: ML19323H279 (2)

Text

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SNUPPS Standardized Nucieer Unit Power Mont System 5 Choke Cherry Road Nicholas A. Petrick Rockville, Maryland 20050 Executive Director N il***oio June 6, 1980 SLNRC 80 27 FILE: 0278.10 SUBJ: IE Bulletin No. 80-05 Mr. Boyce Grier Director, Region I Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 Docket Nos.: STN 50-482, STN 50-483. STN 50-485, STN 50-486

Dear Mr. Grier:

This letter is submitted in response to the subject IE Bulletin for the SNUPPS Utilities, Kansas Gas and Electric Company, Union Electric Company, and Rochester Gas and Electric Corporation.

The design of systems that contain low pressure or holdup tanks and that can be valved to contain primary system water has been reviewed as directed by Bulletin 80-05 The results of this review indicate that dama either 1)gedesign to the provisions tanks due to forvacuum conditions withstanding a fullisvacuum precluded or 2)bythe use of suitable vent connections.

The following systems were included in the review:

a. Reactor Coolant -

b. Chemical and Volume Control

c. Borated Refueling Water

d. High Pressure Coolant Injection

e. Gaseous Radwaste l f. Liquid Radwaste l g. Solid Radwaste l h. Boron Recycle i

The specific incidents at Trojan and Rancho Seco were reviewed to deter-mine if similar events could occur at a SNUPPS plant. The Trojan in-cident involved damage to a CVCS (recycle) holdup tank caused by pres-sure regulator failure. The SNUPPS recycle holdup tanks do not depend on pressure regulators to compensate for level variations, but rather 0

80061203I2 g

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SLNRC 80-27 Page Two use a diaphragm to prevent escape of radioactive gases and absorption of atmospheric gases. The tank gas space is vented to the Radwaste Building HVAC.

The failure of pressure regulators, .as occurred at Trojan, could cause a vacuum to be drawn on the SNUPPS volume control tank. To preclude -

damage, this tank is designed to withstand full vacuum conditions.

Damage to the reactor coolant drain tank (RCDT) similar to that which occurred at Rancho Seco cannot occur at a SNUPPS plant because the SNUPPS RCDT is designed to withstand a pressure differential in excess of full vacuum. In addition, the SNUPPS spent resin storage tank, gas decay tanks, demineralizers, and pressurizer relief tank are cap-able of withstanding a full vacuum without damage.

The remaining tanks in the SNUPPS design (e.g. flocr drain, waste hold-up, laundry and hot shower tanks) are designed to operate at atmospheric pressure. Damage to these tanks from an over- or under-pressure con-dition is precluded by the use of suitable vent connections.

The outside tanks, i.e. the refueling water storage and reactor makeup water storage tanks, are also atmospheric tanks. These tanks are in-sulated and heated to prevent freezing and subsequent vacuum conditions upon pump drawdown of the tank.

Very truly yours,  ;

-Ch<M (

icholas A. Petrick RLS/jdk

' c: Mr. James G. Keppler, Director, Region III, USNRC Mr. Karl V. Seyfrit, Director, Region IV, USNRC

r. Victor Stello, Jr., Director, Office of Inspection and Enforcement, USNRC, Washington, D.C. 20555 .

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