ML18153C888
| ML18153C888 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 01/29/1992 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 91-134F, NUDOCS 9202040096 | |
| Download: ML18153C888 (4) | |
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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 January 29, 1992 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 EXPANSION JOINT REPLACEMENT Serial No.
NL&P/CGL Docket Nos.
License Nos.
91-134F RS 50-280 50-281 DPR-32 DPR-37 As identified in our December 19, 1991 letter (Serial No. 91-134E}, we committed to replace the condenser intermediate outlet expansion joints in the Units 1 and 2 circulating water systems. These replacements were scheduled for completion by February 28, 1992, subject to material availability and the ability to perform the replacement under the existing technical specifications. As also indicated in our December 19, 1991 letter, we intended to perform the replacements with double isolation provided by closure of the associated isolation valve and installation of the seal plates.
Our current assessment of expansion joint replacement activities is discussed below.
To assist in this discussion, a simplified flow diagram illustrating the Unit 1 circulating water and service water systems is attached. The expansion joints immediately downstream of the condenser are referred to as the condenser intermediate outlet expansion joints. One condenser intermediate outlet expansion joint is associated with each circulating water line (A, B, C, and D} on both units. The conclusions of our assessment are as follows:
Replacement of the condenser intermediate outlet expansion joints in the Units 1 and 2 circulating water lines B and D can be accomplished during power operation (with double isolation provided by closure of the associated isolation valve and installation of the seal plates at the high level intake} without entry into any technical specification action statements. Replacement of the expansion joints in the Unit 1 circulating water line Band in the Unit 2 circulating water lines B and D has been completed. Replacement of the expansion joint in the Unit 1 circulating water line D is in progress.
Replacement of the condenser intermediate outlet expansion joints in the Units 1 and 2 circulating water lines A and C during power operation would require technical specification relief if double isolation is provided by closure of the 9202040096 920129 PDR ADOCK 05000280 P
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- associated isolation valve and installation of the seal plates at the high level intake.
This relief would be necessary because isolation of the A and C circulating water lines by installation of the seal plates also results in isolation of the service water cooling the heat exchangers in one outside recirculation spray (RS) subsystem and in one inside RS subsystem.
As discussed during a January 22, 1992 conference call, we have developed an alternate means of double isolation that obviates the need to install seal plates at the high level intake, does not result in isolation of the service water cooling RS heat exchangers and, therefore, does not require technical specification relief.
Instead of installation of the seal plates, the alternate means of double isolation entails the placement of a 1 /16 inch thick 2-ply bithuthene and Ripstop membrane on the condenser inlet tubesheet. The viability of the material and isolation method was verified by a test performed on January 21, 1992. As also indicated during our January 22, 1992 conference call, the test demonstrated satisfactory performance of the material up to a pressure of 80 psi using a test rig which simulated a 36" diameter section of the condenser inlet tubesheet.
The application of this alternate means of double isolation for in-condenser use has been assessed by formal safety evaluation, approved by the Station Nuclear Safety and Operating Committee (SNSOC), and reviewed by management.
Using this alternate means of double isolation, it is anticipated that replacement of the remaining expansion joints will be completed by February 28, 1992.
Our December 19, 1991 letter also indicated that we had installed reduced gap flow shields (with a design gap of s. 1 /8 inch) on the condenser intermediate outlet expansion joints as an interim measure.
Following replacement of the expansion joints, the original flow shield design (with a gap of -1 /2 inch) may be reinstalled, pending completion of an evaluation of the reduced gap flow shield design for permanent installation. This evaluation is scheduled for completion by May 4, 1992.
Should you have questions regarding this information, please contact us.
Very truly yours,
"\\or W. L. Stewart Senior Vice President - Nuclear Attachment - Circulating Water and Service Water Systems Simplified Flow Diagram
cc:
U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, N. W.
Suite 2900 Atlanta, Georgia 30323 Mr. M. W. Branch NRC Senior Resident Inspector Surry Power Station
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