ML20236G464
| ML20236G464 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/29/1987 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| IEIN-86-106, NUDOCS 8708040275 | |
| Download: ML20236G464 (6) | |
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. T ENNESSEE 37401 SN 157B Lookout Place JUL 291987 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - NRC INSPECTION REPORT NOS.
50-327/87-33 AND 50-328/87 REQUEST FOR RESPONSE Enclosed is our response to Gary G. Zech's June 8, 1987 letter to S. A. White that contained a request to provide a summary of actions to be taken to assess the condition of the steam and power conversion systems for each unit. We believe the programs described in the enclosure, as well as our strict control of secondary systems water chemistry, will ensure system operability and integrity.
There are no commitments contained in this submittal.
If you have any questions, please telephone M. R. Harding at (615) 870-6422.
To the best of my knowledge, I declare the statements contained herein are complete and true.
Very truly yours, TENNESSEE VALLEY AUTHORITY R.
idley, D rector Nuclear Safe y and Licensing Enclosure cc:
see page 2 l
870B040275 870729 PDR ADOCK 05000327 G
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An Equal Opportunity Employer
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, l U.S. Nuclear Regulatory Commission k hh h i
ec'(Enclosure):
Mr. G. G. Zech, Assistant Director for Inspection Programs Office of Special Projects U.S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta,-Georgia 30323 k
Mr. J. A. Zwolinski, Assistant Director i
for Projects Division of.TVA Projects office of Special Projects U.S. Nuclear Regulatory Commission 4350 East West Highway EWW 322 Bethesda, Maryland 20814 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee '37379
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ENCLOSURE RESPONSE TO REQUEST NRC INSPECTION REPORT NOS. 50-327/87-33 AND 50-328/87-33 GARY G. ZECH'S LETTER TO S. A. WHITE DATED JUNE 8, 1987
SUMMARY
OF ACTIONS l
irVA has implemented programs to assess the physical condition of the SQN steam and power conversion systems and to demonstrate that the components and systems will operate as intended during startup. Because of the impact of modifications, maintenance, and uncertain startup schedules on plant configuration, no uniform and consistent long-term layup practices were implemented during the outage. The inconsistencies may have contributed to increased oxidation of the secondary system's carbon steel components; but programs have been implemented to identify and remedy degradation from corrosion and erosion of the components. No new or abnormal cleanup activities are planned during startup; however, it is recognized that the normal activities may require a longer duration to provide the proper clarity and purity of water.
Following is a summary of actions taken to assess the condition and integrity of the secondary systems. To ensure that the summary adequately addressed NRC's concerns, additional clarification of the requested assessment was obtained through conversations with the NRC inspector.
The following erosion / corrosion assessment programs and review were implemented.
l 1.
A program has been completed on unit 2 that addressed the concerns expressed in NRC Inspection and Enforcement Notice 86-106.
The program was developed from technical information from.Surry Station' Nuclear Plant, Institute of Nuclear Power Operations (INPO) Network, regional and resident NRC inspectors, and information from references 1 and 2.
The purpose of this program was to determine the high suspect areas and then to inspect and monitor the areas for degradation. The systems that were evaluated were as follows:
(1) condensate, (2) feedwater, (3) extraction steam, (4) heater drain and vent lines, and (5) turbine drain and vent lines.
The inspection plan employed ultrasonic (UT) and metallurgical inspection methods. The program identified any wall thinning because of cavitation (high-pressure differential), pure erosion (high velocity), pure corrosion (low velocity), erosion / corrosion, and any anomalies that would violate the design minimum wall thickness.
Corrective action recommendations were made based on the findings of the inspections. This program has also been l
implemented on unit 1.
l
. f 2.
A review of the adequacy of the layup method used on each major system, on a system-by-system basis, has been performed for each unit. For those systems that were identified as being in a potentially corrosive condition, recommendations were made for improvement of the layup method.
For example, dry layup is being implemented on the unit 1 secondary cycle systems, excluding the steam generators, as recommended by the review.
In addition, an extensive program has been completed in which the operability of the unit 2 components was assessed.
Reviews of the systems and components were accomplished through the following:
1.
Operations reviewed a list of all systems and identified those systems to be evaluated that are needed for operation or safe shutdown.
2.
Acceptance criteria were established for portions of systems where operability could be demonstrated as follows:
a.
System has been operated during the outage; or b.
system has had surveillance instructions (sis) performed on schedule or the sis are scheduled for performance before startup; or c.
major process equipment within the system has met previously established acceptance criteria for each identified component.
3.
The following actions were accomplished for systems for which operability could not be established by number 2 above, Engineers reviewed a list of preventivo maintenance (PM) instructions a.
and identified those cancelled or deferred since 1985 that could affect (degrade) equipment operability.
b.
Engineers reviewed the list of deferred sis to identify any that could affect system operability.
Cognizant engineers established acceptance criteria for each c.
discipline (mechanical, electrical, and instrumentation) and component type that would provide a reasonable assurance that each identified component would be operable for startup.
They determined if testing, PM, and/or maintenance of that component was adequate to satisfy the acceptance criteria.
If not, a comment was provided addressing the acceptance criteria not satisfied.
4.
The results of the review from item No. 3 were compiled on two different forms. The comments listed on the forms were divided into the following three categories:
a.
Recommendations: maintenance or test activitics that are recommended to be performed before startup.
Performance of the activities provided reasonable assurance that the components are acceptable for startup.
. b.
Consideration: maintenance or test activities that, in the opinion of the reviewer, are not essential for startup but should be considered for performance by the responsible maintenance organization.
c.
Considerations for PM Program: maintenance or test activities that should be considered for incorporation into the permanent plant PM program.
The recommendations provided by this program are currently being addressed and tracked as the Equipment Condition Evaluation Program.
Disposition of the recommendations provided by the various condition assessment programs and reviews will provide a high level of assurance that the systems and components will be operable for startup.
O a
<P' REFERENCES 1.
Report by P. Berge and F. Khan, of Electricity De France, dated May 1982,
" Corrosion Erosion of' Steels In High Temperature Water and Wet Steam" 2.
Electric Power Research Institute (EPRI) NP 3944 Report,
" Erosion / Corrosion in Nuclear Plant Steam Piping; Causes and Inspection Program Guidelines" l
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