ML022700151
| ML022700151 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 09/18/2002 |
| From: | Hartz L Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 02-203A | |
| Download: ML022700151 (2) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 September 18, 2002 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Serial No.
NAPS/JHL Docket Nos.
License Nos.
02-203A 50-338 50-339 NPF-4 NPF-7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS I AND 2 CATEGORY I STRUCTURES - SETTLEMENT MONITORING Our letter dated April 3, 2002 (Serial No.02-203) informed you that a revision was made to periodic test procedure 0-PT-1 12, Category 1 Structures - Settlement Monitoring, due to the temporary replacement of a service water expansion joint with a pipe spool piece.
This notification was consistent with the expectations expressed by the Atomic Safety and Licensing Appeal Board in its'decision ALAB-578 (February 11, 1980).
This letter is to inform you that we intend to replace the temporary pipe spool pieces with rubber expansion joints( Metal expansion joints were originally installed in these locations due to the high settlement rates. Settlement rates over the past 10 years have decreased from the original settlement rates. Rubber expansion joints are capable of accommodating the remaining settlement allowed by the Technical Specifications. The rubber expansion joints are constructed of a more durable material than the original stainless steel expansion joints and are not susceptible to corrosion (e.g., general, MIC, etc). Based on industry experience, we believe the rubber expansion joints have an insignificant probability of failure or developing small leaks. No leakage or failures have been observed on similar rubber expansion joints installed on the service water system or on other systems at North Anna.
Atomic Safety and Licensing Appeal Board Decision ALAB-578 documented that the metal expansion joints were the limiting components of the service water system insofar as settlement is concerned.
As such, the Board stated its expectation that a leak detection system should be installed to provide an early warning of any expansion joint leaks. However, the Board specifically stated that the "additional precaution" of a leak 2
detection system was not being required as a condition of the license based on other measures being undertaken which provided reasonable assurance of safety.
The leakage detection system that was installed consisted of a jacket around each metal expansion joint with tubing from each jacket run to a Mercoid level switch.
We intend to eliminate the leakage detection system for the metal expansion joints that are replaced with rubber expansion joints.
We do not intend to replace the leak detection system based on decreased settlement rates and since the rubber expansion joints are not susceptible to cracking from the remaining potential settlement stress.
The rubber expansion joints will be inspected on a periodic basis in accordance with our preventive maintenance program and replaced in accordance with the manufacturer's warranty.
If you have any questions, please contact us.
Very truly yours, Leslie N. Hartz Vice President - Nuclear Engineering Commitments made in this letter: None cc:
U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 23T85 Atlanta, Georgia 30303-8931 Mr. M. J. Morgan NRC Senior Resident Inspector North Anna Power Station