ML20087B511
| ML20087B511 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 07/25/1995 |
| From: | Mccollum W DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20087B519 | List: |
| References | |
| NUDOCS 9508080143 | |
| Download: ML20087B511 (5) | |
Text
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, Duke 1%wer Cornpany (803)&11 3000 Catawba Nuclear Station l
- 4800ConcordRoad
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. DUKEPOWER.
July 25,1995 s%U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555
Subject:
Catawba Nuclear Station, Unit 2 Docket No. 50-414 Request for Relief Number 95-04 L
Gentlemen:
l Pursuant to 10 CFR 50.55a(f)(6)(i), please find attached Request for Relief Number 95-
- 04. This request seeks relief from certain hydrostatic testing requirements for the Containment Valve Injection Water (NW) System. The details of this relief request are -
explained fully in the attachment.
Catawba plans to utilize the described alternative test for the refiseling outage at the end of l
cycle 7 (EOC 7) beginning October 1,1995. Therefore, NRC approval of this relief request is requested by October 1,1995.
- If you have any questions pertaining to this relief request, please call L.J. Rudy at (803).
831-3084.
Very truly yours, W.R. McCollum l~
Catawba Site Vice President l-LJR/s Attachment OSD1N F
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t, Document Control Desk Page 2 July 25,1995 xc (with attachment):
S.D. Ebneter, Regional Administrator Region II R.J. Freudenberger, Senior Resident Inspector R.E. Martin, Senior Project Manager ONRR
n Duke Power Company Station Catawba Unit 2
10-YEAR INTERVAL REQUEST FOR RELIEF NO.
95-04 Page 1 of 2 1.
System / Component (s) for Which Relief is Requested:
The system hydrostatic testing cn the Containment Valve injection Water System (NW). The NW system prevents leakage of containment atmosphere past certain gate valves used for containment isolation following a loss of coolant accident (LOCA). This prevention is performed by injecting seal water at a pressure exceeding containment accident pressure between the two seating surfaces of the flex wedge valves.
The system consists of two independent, redundant trains; one supplying gate valves that are powered by the A train emergency diesel generator and the other supplying gate valves l
powered by the B train emergency diesel generator.
Reference the attached Catawba Unit 1 examination boundary drawing (CNL-1569-1.0).
The NW pressure retaining components required for examination are shown in yellow. The Unit 2 examination boundary is the same as the Unit 1 examination boundary. The Unit 1 examination boundary drawing is used as an example because the Unit 2 examination boundary drawing is in the course of preparation.
l 11.
Code Requirement:
Section XI, Table IWC-2500-1, Examination Category C-H; Items C7.20, C7.40,
& C7.80.
Ill.
Code Requirement from which Relief is Requested:
Re!ief is requested from performing the required system hydrostatic test (IWC-5222) and associated VT-2 examination.
IV.
Basis for Relief:
Although the NW surge chambers are maintained greater than 38 psig, the NW system piping is not pressurized during normal plant operation; therefore, the use of Code Case N-498 is not practical. The NW system has Class 2 piping on adjacent sides of the containment penetration isolation valves; therefore, the use of Code Case N 522 is not practical. Since hydrostatic testing would involve pressurizing the NW piping up to each containment isolation valve that the system serves, the potential exists for NW fluid to be injected into the process line in which the isolation valve is contained. This water intrusion could f
cause a variety of problems including slight dilution of the Safety injection system or the Chemical and Volume Control system.
1
Duka Pow:;r Company Station Catawba Unit 2
10-YEAR INTERVAL REQUEST FOR RELIEF NO.
95-04 Page 2 of 2 V.
Alternate Testing:
In lieu of the IWC-5222 hydrostatic test, the following alternative testing will be performed:
The containment isolation valves served by the NW system together with the NW system will be tested simultaneously. The NW system will be pressurized to 21.10 Pa (10% above design containment pressure) and then leak rate tested by injecting seal water to the containment isolation valves. To assure that an open path exists to each containment isolation valve, individual valves will be opened and the NW surge chamber level verified as decreasing. Once an open path to each containment isolation valve has been verified, and the containment isolation valvo closed, the overall system leakage will be determined by measuring the flow rate of seal water out of the NW surge chamber. Leakage will be measured using either process flow meters or by measuring the drop in the NW surge chamber level over a period of time and calculating the volume of water per unit time. Total containment isolation valve seat leakage allowed is
(
equal to or less than 1.19 gallons per minute with the NW surge chamber pressure greater than or equal to 38 psig for NW train "2A" and equal to or less than 1.12 gallons per minute with the NW surge chamber pressure greater than or equal to 38 psig for NW train "2B".
VI.
Justification for the Granting of Relief:
The purpose of the Code required pressure test is to ensure system integrity.
The Code required test cannot be performed in such a manner as to ensure system integrity without risking dilution of the Safety injection system or the Chemical and Volume Control system. The alternative test as stated in section V above will be conducted during each refueling outage and is designed to ensure the NW system is capable of performing its safety function. Leakage above the acceptance criteria stated in section V above will be evaluated for corrective action.
l Vll.
Implementation Schedule:
l Duke Power Company plans to use the requested alternative test for the refueling outage at the end of cycle 7 (EOC 7) beginning October 1,1995.
Evaluated By:
hvy\\ b ean Date
'l[24 f 95 h)
Reviewed By:
M MWL Date 1 73 9b
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