ML20133E499
| ML20133E499 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 12/18/1984 |
| From: | Domer J TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8507220520 | |
| Download: ML20133E499 (4) | |
Text
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 1630 Chestnut Street Tower II 25 P l* 2.6 g}g{C December 18, 1984 U.S. Nuclear Regulatory Commission Region II ATTN:. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia' 30323
Dear Mr. O'Reilly:
Enclosed is our response to J.'A. Olshinski's November 19, 1984 letter to
~
H. G. Parris transmitting IE Inspection Report Nos. 50-259/84-40,
-260/84-40, -296/84-40 for our Browns Ferry Nuclear Plant which appeared to have been in-violation of NRC regulations. If you have any questions, please call Dennis McCloud at FTS 858-2725.
To the best of_my knowledge, I declare the statements contained herein are complete and true.
Very truly yours, TENNESSEE VALLEY AUTHORITY 8R1J4.,
J. A. Domer Nuclear Engineer Enclosure 8507220520 841218 PDR ADOCK 05000259 G
PDR I
An Equal Opportunity Employer
4 s
RESPONSE
NRC INSPECTION REPORT NOS.
50-259/84-40, 50-260/84-40, AND 50-296/84-40 JOHN A. OLSHINSKI'S LETTER TO H. G. PARRIS DATED NOVENBER 19,198a The following violation was identified during an inspection conducted on October 15-19, 1984. The Severity Level was assigned in accordance with the NRC Enforcement Policy (10 CFR Part 2, Appendix C).
Item 1 - (50-259/260/296/84-40-01) 10 CFR 50, Appendix B, Criterion V, as implemented by Topical Report TVA-TR75-1A, requires the licensee to provide appropriate acceptance criteria in instructions to assure that important activities are satisfactorily accomplished.
Contrary to the above, the licensee's instructions for leakage rate tests on pressure isolation valves (surveillance instructions (sis) 3.2.5 and 4.7. A.2.g-3) do not provide appropriate acceptance criteria for leakage rates in that:
1.
Although the instructions provide reference leakage rate acceptance limits that would assure correction of degraded leak tightness for the valves, these limits may be bypassed on the verbal approval of the NDE Level III qualified person, who may permit leakage through redundant pressure isolation valves up to the relief capacity of the relief valves in the lower pressure systems which accept the leakage.
2.
The maximum leakage that could be permitted as a result of the above would eliminate the capability of the relief valves to serve their protective functions in subsequent plant operation. They would not protect the lower pressure piping from further increases in leakage or thermal transients that might occur during plant operation - such that low pressure piping component might be degraded or failed, resulting in a loss of coolant outside the primary containment.
3 Permissible leakage might result in raising the temperature of the lower pressure piping above that intended by design.
4.
Once accepted, leakage rates as high as the relief capacities of the relief valves could remain unchecked for an entire operating cycle -
possibly as long as two years.
5.
The criteria used by the NDE Level III test person in determining what limits he should permit were not prescribed or referenced by the i
instructions.
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This is a Severity Level IV violation (Supplement I).
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Admission or Denial of the Alleged Violation TVA admits the alleged violation parts 2-5 'only.
2.
Reasons for the Violation Surveillance Instruction (SI) 4.7.A.2.g-3 is used to comply with the surveillance requirements 4.7. A.2.g-i which provide limitations for primary containment isolation valve leakage-rates.
The Technical Specification (TS) require isolation valve leak rate testing be performed in accordance with 10 CFR 50, Appendix J.
Both the TS and Appendix J are concerned with allowable leakage (L ) of the primary containment.
L* is the sum of all the leakage. pat $s from pr19ary containment.
In order to fully understand the alleged violation, parts 1-5 above, the ASME section XI, subsection IWV must be addressed. The requirements of ASME section XI are also required to be met by the TS.
SI 3.2.5 is used to comply with the ASME section XI, subsection IWV.
SI 3 2.5 uses data obtained by SI 4 7.A.2.g-3 The data is extrapolated to design conditions and compared to ASME section XI requirements. ASME section XI requirements are based on the capacity of the relief valve on the low pressure side of the given isolation valve.
With reference to alleged violation, part 1 above, SI 4.7. A.2.g-3 does not use relief valve capacities, only the L for the sum of all primary containment leakage paths. However" SI 3 2.5 does use relief valve capacities in detemining acceptable isolation valve leakage rates. SI 3 2.5 requires that valve testing f.'equency be doubled if a valve's leakage has increased by 50 percent or more. It is true that a valve could exceed its' maximum leakage rate if the initial leakage rate was already 50 percent or more of the allowable leakage rate requirement.
Alleged violation part 5 above is inaccurate in that the level III NDE person has criteria for acceptable valve leakage. SI 4.7.A.2.g-3 explicitly provides the allowable L,.
Each individual component tested has an allowable reference leakage rate which is a percentage of the maximum allowable leakage rate L,.
The reference leakage rates are detemined to ensure L is not exceeded.
When a component is tested and exceeds its @ererence leakage rate, the level III NDE person checks the impact of this component's leakage rate on L to ensure it is not exceeded. If sufficient margin exists, the level *III NDE person can approve a components leakage rate to be in excess of its reference leakage rate. This is the process that is used to ensure L is never exceeded. SI 4.7. A.2 3 does not contain a paragraph statfng this sequence of events. It only requires documenting that L, is not exceeded.
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Corrective Steps Which Have Been Taken and Results Achieved As discussed above in item 2,'SI 4.7.A.2.g-3 meets its intended function; however, a change has been detemined to be needed to clarify how the L is not exceeded. SI 3.2.5 has been reviewed and detemined to need' revising.'
4.
Corrective Steps Which Will Be Taken To Avoid Further Violations SI 4.7. A.2.g-3 will be revised to include an outline of how the level III'NDE person uses the reference leakage rates and what action la
-taken to prevent the L from being exceeded.
(reference alleged violation part 5)
SI 3 2.5 will be revised to require that any category A valve that exceeds 50 percent of the leakage requirement will be repaired to reduce the leakage rate to below 50 percent of required. Also, the latest SI 3.2 5 data will be reviewed for possible excessive leakage rates. This will ensure that allowable leakage is maintained below relief valve capacity.
(reference alleged violations 2-4) 5.
Date When Full Compliance Will Be Achieved Full compliance will be achieved by February 1,1985, when SI 3.2.5 and 4.7. A.2.g-3 are revised.
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