ML20050B590
| ML20050B590 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 04/01/1982 |
| From: | Leasburg R VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Harold Denton, Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0578, RTR-NUREG-0737, RTR-NUREG-578, RTR-NUREG-737, TASK-2.D.1, TASK-TM 197, NUDOCS 8204060095 | |
| Download: ML20050B590 (4) | |
Text
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Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation N0/DWS.Jr.:acm Attn:
Mr. Darrell C. Eisenhut, Director Docket Nos. 50-338 Division of Licensing 50-339 U. S. Nuclear Regulatory Commission License Nos. NPF-4 Washington, D. C. 20555 NPF-7 Gentlemen:
Response to NUREG 0737 Post-TMI Requirement-Item II.D.1 Relief & Safety Valve Test Requirements Preliminary Review of Generic Test Program North Anna Power Station In accordance with the initial recommendacion of NUREG 0578, Section 2.1.2 as later clarified by NUREG 0737, Item II.D.1 and revised September 29, 1981, each Pressurized Water Reactor (PWR) Utility on or before April 1, 1982, was to submit information relative to the pressurizer safety and relief valves in use at their plant.
Specifically this submittal should include a preliminary evaluation supported by test results which demonstrates the capability of the relief and safety valves to operate under expected operating and accident' conditions.
This letter is the response of Virginia Electric & Power Company to the April 1, 1982, USNRC submittal request and is applicable to the North Anna Unit 1 and Unit 2 Plants.
The Virginia Electric & Power Company has actively pursued resolution of this issue through direct participation in the Electric Power Research Institute (EPRI) valve test program.
The primary objective of the Test Program was to provide full scale test data confirming the functionability of the primary system power operated relief valves and safety valves for expected operating and accident conditions. The second objective of the program was to obtain sufficient piping thermal hydraulic load data to permit confirmation of models which may be utilized for plant unique analysis of safety and relief valve discharge piping systems.
Relief valve tests were completed in August 1981 and safer.y valve tests were completed in December 198;.
The reports prepared for the EPRI Test Program and referenced in this submittal include:
f OY (1) " Valve Selection / Justification Report" s
r This report documents that the selected test valves represent all participating PWR safety and relief valves.
! h 8204060095 820401 PDR ADOCK 05000338 p
visoissa necraic no Powsm COMP MY TO (2) " Test Condition Justification Report" and the (3) " Valve Inlet Fluid Conditions for Pressurizer Safety and Relief Valves in Westinghouse Designed Plants" These reports document the basis and justification of the valve test conditions for all participating PWR plants.
(4) " Safety and Relief Valve Test Report" This report provides evidence demonstrating the functionability of the selected test valves under the selected test conditions for all participating PWR plants.
All of these documents have been received by the Virginia Electric & Power Company. Additionally, they have been transmitted to you by David Hoffman of the Consumers Power Company on behalf of the participating PWR Utilities.
Virginia Electric & Power Company has undertaken review of these documents but the review, at present, is preliminary due to the preliminary nature of the test data received to date.
Power Operated Relief Valve (PORV)
The PORV's at the North Anna Units are:
Manufacturer - Masonellan International Type - 20,000 Series Size & Description - 2" NPS, Quick Change Trim Quantity - 2/ unit These valves have been tested by EPRI in a test configuration similar to that of the actual pressurizer configuration at the plant.
The fluid conditions for the PORV's, while not specifically addressed in the North Anna Units I and 2 Final Safety Analysis Report, were identified by Westinghouse and are discussed in the Fluid Conditions Justification Report, EPRI Report (3).
The fluid conditions for the tests were selected on the basis of enveloping those fluid conditions for all plants utilizing the same valve type (2).
Tests were performed both at the Marshall Steam Station and at the Wyle tect facility (Phase III).
A total of 22 tests were conducted utilizing steam, water, and steam-to-water transition fluid conditions.
These tests confirmed that the valve opened and closed on demand and that the valve suffered no damage that would preclude future operation.
Specific information related to these tests is given in Section 4.5 of the " Safety and Relief Valve Test Report", EPRI Report (4).
n llarold R. Denton visoissa Etretase amp Powen Comry To Saiety Valves The safety valves at the North Anna Units are:
Manufacturer - Dresser Industrial Valve & Instrument Division Model No. - 31759A Size - 3 x 6 Quantity - 3/unis These valves have not been tested by EPRI.
However, safety valves similar in design and operation have been tested in a test configuration at the (EPRI)
Combustion Engineering Test site.
Justification that the valves tested envelope those valves at the North Anna Units is given in the Valve Justification Report.
EPRI Report (1).
Justification that the fluid conditions for the tests envelope the actual plant conditions is presented in EPRI and Westinghouse Reports (2,3).
The safety valves have been shown to open and close.
Certain areas of system performance are still undergeing review, specifically addressing the inlet piping wtlet piping and the valves.
The Virginia Electric & Power Company is ac t.,
>y involved with the Westinghouse Owners Group program and had additiona
'y contracted Westinghouse to evaluate the specific North Anna Unit I and Unit 2 Pressurizer Safety and Relief Valves results. All relevant EPRI results will be employed in the evaluation.
Clarification of concerns and their impact on plant performance is expected prior to the July 1,
- 1982, information submittal date.
Based on our review, we have concluded that the valves tested represent the safety and relief valve designs and that the conditions tested envelope the range of expected operating and accident conditions for the North Anna Units 1 and 2.
The EPRI reports provide the information required by NUREG 0737, Item II.D.I. A and will be used to perform the final plant specific evaluations.
Also in progress at this time is our analysis of the relief and safety valve discharge piping adequacy by Stone & Webster Engineering Corporation.
The North Anna analysis is based on modifying the existing pressurizer piping system to provide a drain to remove loop ecil water.
We have reached this decision based on preliminary results of the generic EPRI testing program which indicates high discharge piping loads are created by a loop seal water slug release.
Based on these generic results, our engineering judgement is to provide a loop seal drain to eliminate the water and any consequent high discharge piping loads.
The analysis of the piping for the modified system will include the effect of steam hammer on both the inlet and discharge piping.
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vimoi,iA hECTRIC AMD IbwEk COMPANY 70 The Sep:2mber 29, 1981, USNRC letter requcted that plant t.pecific final evaluations be submitted by July 1,
1982.
In c.rd e r to meet that date, evaluations have been initiated.
Depending on the outcome of the evaluations, it may be necessary to continue the evaluation beyond July 1, 1982.
If a longer evaluation period is required you will be notified on or before July 1, 1982.
Very truly yours, c
% R.11. Leasburg cc:
Mr. James P. O'Rollly, Regional Administrator Office of Inspection and Enforcement Region 11 Mr. Steven A. Varga, Chief Operating Reactorn Branch No. 1 Division of Licensing