ML20005E056
| ML20005E056 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/26/1989 |
| From: | Medford M TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9001030184 | |
| Download: ML20005E056 (3) | |
Text
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6N 38A Lookout Place I
DEC 161989 I
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk
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Washington, D.C.
20555 L
Gentlemen:
In the Matter of-.
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Docket Nos. 50-327-Tennessee Valley Authority
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S0-328 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - NRC INSPECTION REPORT NOS. 50-327, 328/89 REVISED CORRECTIVE ACTION FOR NOTICE OF VIOLATION (NOV) 50-327, 328/89-16-02
Reference:
TVA's response to NRC dated July 20, 1989, "Sequoyah Nuclear Plant (SQN) Units 1 and 2 - NRC Inspection Report Nos. 50-327, 328/89 Response.to Notice of Violation (NOV) S0-327, 328/89-16-02" Part of the corrective action taken by TVA in the referenced NOV response was a revHlon to Surveillance Instruction (SI) 137.2, " Reactor Coolant System Water Inventory," to require one of the following actions if the unidentified leakage calculated during reactor coolant system (RCS) leakage surveillance is determined to be negative:
1.
Additional. data will be taken (or repeat that test) and the unidentified leakage will be recalculated.
2.
The total leakage (identified and unidentified) will be classified as unidentified and subject to the unidentified leakage acceptance criterion.
The SI-137.2 revision also specified that if a trend of negative leakages is identifted.. Systems Engineering will be nottfled to investigate possible sources of non-RCS inleakage.
In a leak-tight RCS, occasional calculation of small, negative unidentified leakage is to be expected.
To appropriately allow for such occurrences, SI-137.2 has been revised again to specify the following steps:
1.
If after two hours of data collection the unidentified leakage is calculated to be negative, then the calculations will be reperformed using a minimum of one hour of additional data.
(At the user's discretion, any 2-hour block of data can be used as long as test prerequisites are maintained.)
2.
Unidentified leakages as low as -0.10 gallon per minute (gal / min) can be tolerated and included in the test results.
l 3.
If unidentified leakage is less than -0.10 gal / min, the test will continue l
until an acceptable leakage (greater than or equal to -0.10 gal / min) is f
calculated or until the test must be aborted.
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4.
If an unidentified leakage greater than or equal to -0.10 gal / min cannot be obtained, or if four consecutive SI-137.2 packages indicate negative unidentified leakage, an investigation will be performed by Systems Engineering and Operations to determine the source of non-RCS inleakage.
1he above revisions to SI-137.2 were implemented on October 5, 1989, after discussing the changes with Paul Burnett, of NRC Region II, who conducted Inspection 50-327, 328/89-16.
One additional change has also been made to SI-137.2.
The measured value of RCS total leakage. reflects any real RCS outleakage through volume control tank or pressurizer level changes. Conversely, the measured value of identified leakage reflects the result of both RCS leakage into tanks and any RCS inleakage through tank level changes such as in the reactor coolant drain tank.
The calculated unidentified leakage is simply the difference between the total and identified leakages.
In some cases, RCS inleakage can cause calculated identified leakage to exceed total leakage, thereby resulting in negative unidentifled leakage.
Thus, negative unidentified leakage may indicate the existance of RCS inleakage which, in sufficient magnitude, could possibly hinder the recognition of excessive RCS outleakage. To preclude this possibility, the following action was added to SI-137.2 on November 30, 1989.
5.
If unidentified leakage remains less than or equal to -0.10 gal / min, satisfaction of technical specification surveil.ance requirements will depend on the amount of total RCS leakage.
If total RCS leakage is less than or equal to 1.0 gal / min, then surveillance requirements have been met, and the SI package can be closed out.
However, if total RCS leakage is greater than 1.0 gal / min, then the SI package must be aborted or remain open until either unidentified leakage is greater than or equal % -0.1 gal / min or total RCS' leakage is less than or equal to 1.0 gal / min The provisions of Technical Specification 4.0.3 are applicable if the 4 package is not completed on time.
If you have any questions concerning this submittal, please telephone M. A. Cooper at (615) 843-6651.
Very truly yours, TENNESSEE VALLEY AUTHORITY hh Mark 0. Medford, Vice resident Nuclear Technology and Licensing cc: See page 3 i
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.U.S. Nuclear Regulatory Commission DEC26 M 5
o cc:' Ms.'S. C. Black, Ast.istant Director for Projects TVA Projects Division U.S'. Nuclear Regulatory Commission
- fo One White Flint, North-11555 Rockville Pike Rockville', Mary'and 20852 Mr. B. A. Wilson, Assistant Director for Inspection Programs TVA Projects Division j
U.S. Nuclear Regulatory Commission 3
Region.Il 101 ffarietta Street, NW, Suite 2900 Atl'anta, Georgia '30323-NRC Resident Inspector Sequoyah Nuclear Plant 2600 Iguu Ferry Road j
(L Soddy Daisy, Tennessee 37379 i
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