ML20247D298
| ML20247D298 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/20/1989 |
| From: | Medford M TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8907250149 | |
| Download: ML20247D298 (3) | |
Text
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.s TENNESSEE VALLEY AUTHORITY CH ATTANOOGA, TENNESSEE 37401 6N 38A Lookout Place JUL f 01989 U.S. Nuclear Regula ary Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
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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, 328/89 RESPONSE TO NOTICE OF VIOLATION (NOV) 50-327, 328/89-16-02 Enclosed is TVA's response to B. A. Wilson's letter to 0. D. Kingsley, Jr.,
dated June 20, 1989, that transmitted the subject NOV.
If you have any questions concerning this submittal, please telephone M. A. Cooper at (615) 843.6651.
Very truly yours, TENNESSEE VALLEY AUfHORITY,
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Mark O. Medford, Vice resident and Nuclear Technical Director Enclosure cc (Enclosure):
Ms. S. C. Black, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Wilson, Assi.stant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Regico II 101 Natietta Street, NW, Suite 2900 Atlanta, Georgia 30323 NRC Resident Inspector
/g Sequoyah Nuclear Plant M
2600 Igou Ferry Road
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il Soddy Daisy, Tennessee 37379 8907250149 890720 PDR ADOCK 05000327 Q
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An Equ.: Opportunity Employer
Jo.(*7 ENCLOSURE RESPONSE TO NRC INSPECTION REPORT NOS. 50-327, 328/89-16
'B. A. WILSON'S LETTER TO 0. D. KINGSLEY, JR.
-DATED JUNE 20, 1989 Violation 50-327, 328/89-16-02
" Technical-Specification 6.8.1.a and Regulatory Guide 1.33, Appendix A, Paragraph 8 requires-implementation of surveillance and test procedures.
Contrary to the above, surveillance procedure SI-137.2 in use on May 9, 1989, did not. adequately account for reactor coolant system leakage measurements which result in negative unidentified leakage.
Negative reactor coolant.
system unidentified leakage is a physical impossibility, but can result from problems such as improperly calibrated level instrumentation or in leakage of fluid from non-reactor coolant system sources.
Both of these examples could-result in the. masking'of.the true unidentified leakage, potentially to the extent that the 1.0 gpm technical specification limit may be unknowingly exceeded. On May 9,1989, the inspector noted that negative unidentified-leakage results-from measurements taken on April 14 and 27 May 1, 2, and 8,1989, were accepted without documented justification or further review.
This is a Severity Level IV violation (Supplement I)."
Admission or Denial of the Alleged Violation TVA admits the violati.on.
i Reason for the Violation The reason for the violation was a failure to consider the possibility that a negatively valued, unidentified leakage might be caused by nonreactor coolant system (non-RCS) leakage into the test boundary during performance of
. Surveillance Instruction (SI) 137.2, " Reactor Coolant System Water Inventory." Consequently, the SI-137.2 acceptance criterion for unidentified leakage _was less than one gallon per minute with no prohibition against accepting negattvely valued leakage.
l Occasional occurrences of calculating small, negative, unidentified leakages l
were considered to be the result of instrument tolerances and, thus, numerical l_.
aberrations of little significance.
For this reason, small values of negative, unidentified leakage were deemed acceptable during performance of I
SI-137.2 on several occasions.
~As a result of the perspective introduced by the NRC inspection team during
-In'pection 89-16, TVA now recognizes that accepting negatively valued, s
unidentified leakage during performance of SI-137.2 is technically unacceptable.
Non-ACS leakage into the test boundary during the surveillance could be occurring and masking other unidentified RCS outleakage.
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"- Corrective Steps That Have Been Taken and Results Achieved To correct this problem, SI-137.2 has been revised to require one of the following actions if the calculated unidentified leakage is determined to be negative:
1.
That additional-data be taken (or repeat the test) and the unidentified leakage recalculated, or, 2.
That the total leakage (identified and unidentified) be classified as unidentified and subject to the unidentified leakage acceptance criterion.
In addition, if a trend of negative leakages is identified, the procedure now requires that System Engineering be notified to investigate possible sources of non-RCS inleakage.
This procedure revision will prevent acceptance of negative unidentified leakage results and will promote identification of any sources of non-RCS inleakage that could be masking other unidentified RCS outleakage.
Corrective Steps That Will Be Taken to Avoid Further Violations No further corrective actions are required.
Date When Full Compliance Will Be Achieved TVA is currently in full compliance.
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