ML20134C968
| ML20134C968 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 10/04/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20134C964 | List: |
| References | |
| NUDOCS 9610110194 | |
| Download: ML20134C968 (6) | |
Text
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Ji UNITED STATES j
j NUCLEAR REGULATORY COMMISSION
~f WASHINGTON, D.C. 20666-4001
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SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 234 TO FACILITY OPERATING LICENSE NO. OPR-59 POWER AUTHORITY OF THE STATE OF NEW YORK JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333
1.0 INTRODUCTION
On September 12, 1995, the U.S. Nuclear Regulatory Commission (NRC) approved issuance of a revision to 10 CFR Part 50, Appendix J, " Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors" which was subsequently published in the Federal Reaister on September 26, 1995, and became effective on October 26, 1995.
The NRC added Option B " Performance-Based Requirements" to allow licensees to voluntarily replace the prescriptive testing requirements of 10 CFR Part 50, Appendix J, with testing requirements based on both overall leakage rate performance and the performance of individual components.
By application dated March 27, 1996, as supplemented by letters dated April 24, 1996, and August 15, 1996, the New York Power Authority (the licensee or the authority) requested changes to the Technical Specifications (TSs) for James A. FitzPatrick (JAF) Nuclear Power Plant.
The proposed changes would permit implementation of 10 CFR Part 50, Appendix J, Option B by referencing Regulatory Guide (RG) 1.163, " Performance-Based Containment Leak Test Program," dated September 1995. The licensee has established a
" Containment Leakage Rate Testing Program" and proposed adding this program to the TS. The April 24, 1996, supplemental letter was not outside the scope of the original notice of the application in that it addressed the reverse flow type C testing of 17 valves as provided for in JAF TSs and did not affect performance based leakage testing. The August 15, 1996, supplemental letter provided clarifying information that was not outside the scope of this original notice of the application.
2.0 BACKGROUND
Compliance with 10 CFR Part 50, Appendix J, provides assurance that the primary containment, including those systems and components which penetrate the primary containment, do not exceed the allowable leakage rate specified in the TS and Bases. The allowable leakage rate is determined so that the leakage assumed in the safety analyses is not exceeded.
9610110194 961004 PDR ADOCK 05000333 P
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On February 4,1992, the NRC published a notice in the Federal Reaister (57 FR 4166) discussing a planned initiative to begin eliminating requirements marginal to safety which impose a significant regulatory burden. Appendix J of 10 CFR Part 50 was considered for this initiative and the staff undertook a study of possible changes to this regulation. The study examined the previous i
performance history of domestic containments and examined the effect on risk of a revision to the requirements of Appendix J.
The results of this study are reported in NUREG-1493, " Performance-Based Leak-Test Program."
Based on the results of this study, the staff developed a performance-based approach to containment leakage rate testing. On September 12, 1995, the NRC approved issuance of this revision to 10 CFR Part 50, Appendix J, inhich was i
subsequently published in the Federal Reaister on September 26, 1995, and 4
became effective on October 26, 1995. The revision added Option B
" Performance-Based Requirements" to Appendix J to allow licensees to voluntarily replace the prescriptive testing requirements of Appendix J with testing requirements based on both overall and individual component leakage rate performance.
Regulatory Guide 1.163, was developed as a method acceptable to the NRC staff for implementing Option B.
This RG states that the Nuclear Energy Institute (NEI) guidance document NEI 94-01, " Industry Guideline for Implementing Performance-Based Option of 10 CFR Part 50, Appendix J" provides methods acceptable to the NRC staff for complying with Option B with four exceptions which are described therein.
Option B requires that the RG or other implementation document used by a licensee to develop a performance-based leakage rate testing program must be included, by general reference, in the plant TS. The licensee has referenced RG 1.163 in the JAF TS.
Regulatory Guide 1.163 specifies an extension in Type A test frequency to at least one test in 10 years based upon two consecutive successful tests. Type B tests may be extended up to a maximum interval of 10 years based upon completion of two consecutive successful tests and Type C tests may be extended up to 5 years based on two consecutive successful tests.
By letter dated October 20, 1995, NEI proposed TS to implement Option B.
After some discussion, the staff and NEI agreed on final TS which were attached to a letter from C. Grimes (NRC) to D. Modeen (NEI) dated November 2, 1995. These TS are to serve as a model for licensees to develop plant specific TS in preparing amendment requests to implement Option B.
For a licensee to determine the performance of each component, factors that are indicative of or affect performance, such as an administrative leakage limit, must be established. The administrative limit is selected to be indicative of the potential onset of component degradation. Although these limits are subject to NRC inspection to assure that they are selected in a reasonable manner, they are not TS requirements. Failure to meet an administrative limit requires the licensee to return to the minimum value of the test interval.
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'. Option B requires that the licensee maintain records to show that the criteria for Type A, B and C tests have been met.
In addition, the licensee must maintain comparisons of the performance of the overall containment system and the individual components to show that the test intervals are adequate. These records are subject to NRC inspection.
3.0 EVALUATION 3.1 Option B The licensee's March 27, 1996 letter, supplemented by the April 24, 1996, and August 15, 1996, letters to the NRC proposes to establish a " Containment Leakage Rate Testing Program" and proposes to add this program to the TS.
1 The program references RG 1.163, which specifies a method acceptable to the NRC for complying with Option B, with an exception for Type C testing of primary containment isolation valves in the reverse (non-accident) direction.
This requires a change to existing TS 4.7-2 and the addition of the i
" Containment Leakage Rate Testing Program" to Section 6.20.
Corresponding bases were also modified.
3.2 Reverse F Testing I
Periodic Type C testing in the reverse (non-accident) direction for primary containment isolation valves does not expose potential atmospheric leakage 4
paths (e.g., valve stem packing) to test pressure. Therefore, it can not be 1
quantitatively shown that Type C test results are rat affected in a non-conservative manner by testing in the reverse direction.
Section 8.0 of NEI 1
94-01, REV. O, requires that potential leakage paths to atmosphere be 1
quantitatively determined. At FitzPatrick, reverse direction testing of 17 of these valves is required due the inability to isolate the valves from the containment and the lack of test connections. These valves are reverse direction tested in accordance with the current FitzPatrick TS Table 4.7-2,
" Exception to Type C Tests."
Type C testing in the reverse direction for these valves provides equivalent or more conservative results than testing in the accident direction, with respect to seat leakage. With respect to the globe valves, the test pressurization is under the seat, which tends to unseat the valve. With respect to the butterfly valves, measured leakage is independent of the direction of test pressure from both a force exerted and seating surface standpoint.
Modifications have been considered by the licensee that would allow testing in the accident direction or allow potential leakage to atmosphere to be quantitatively determined. The addition of block valves and test connections to allow accident direction testing would increase design complexity, provide additional potential leakage pathways, and increase loading on piping penetrating primary containment. Valve stem packing modifications to allow
potential leakage to be quantitatively determined would increase design complexity, and provide additional potential leakage pathways.
There is a low safety significance associated with this proposal because:
1.
Testing of these valves during the 1995 Integrated Leakage Rate Test (ILRT) verified that the packing glands were insignificant contributors to the overall integrated leakage rate. The 1995 as-left ILRT leakage rate was 0.0629% weight / day, which was well below the current TS acceptance criteria of 0.5% weight / day.
2.
Adding the results of the 1995 As-Left Type A, B, and C tests together (approximately 2188 SCFD) results in a leakage total well below 0.6L (3216 SCFD). ThisconservativelyshowsthatsignificantmarginexisIs to exceeding TS or Appendix J limits.
3.
Review of past ILRT results indicates that the 17 valves have not been the cause of an ILRT failure. Based on a review of the maintenance history for each valve, recurring packing or body to bonnet leaks are not expected.
4.
The valve stem packing and body to bonnet gaskets are resilient materials designed to conform to sealing surfaces.
The valves are installed in systems which are not normally subjected to design flows, temperatures, or pressures. During normal operation, the valve stem packing and body-to-bonnet gaskets are exposed to the primary containment atmosphere, which has a low oxygen content.
Based on this, the degradation of the valve stem packing or body-to-bonnet gaskets due to continuous exposure to a harsh environ'nent is not a significant concern.
5.
From a risk perspective evaluation, the elimination of modifications that would allow testing in the accident direction or allow potential leakage to atmosphere to be quantitatively determined, can be justified using the technical bases provided for NUREG-1493.
Past studies show that overall reactor accident risks are not sensitive to variations in containment leakage rate, within one or two orders of magnitude of La, the allowable containment leakage rate. This is because reactor accident risks are dominated by accident scenarios in which the containment fails or is bypassed. Such scenarios, even though they are of very low probability, dominate the predicted accident risks due to their high consequences.
FitzPatrick Individual Plant Examination (IPE) results are consistent with these past technical studies.
Certain NRC sponsored studies indicate that overall plant risk is not sensitive to changes in containment leak rates. The incremental risk from leakage in the range of 1% to 10% per day is small.
FitzPatrick and Peach Bottom, which were subjects of.the studies, are both BWR 4 plants with MARK I containments.
Similar results are expected for FitzPatrick.
The analysis described above provides justification that potential leakage paths to atmosphere for these 17 valves are unlikely to be significant and that the associated risk to public health and safety is insignificant.
The Authority proposes that a soap bubble test be performed on the pressurized stem / bonnet boundaries of the 17 valves during regularly scheduled Type A testing. To provide a direct indication of the leak-tightness of the packing and body-to-bonnet gaskets, the Authority will use the acceptance criterion of zero bubbles for this test. Type C testing will be performed, as a post-work test, following work activities that affect the potential atmospheric leakage paths on any of the 17 valves. A soap bubble test will then be performed on the subject valve (s) at regularly scheduled Type A test intervals. These requirements will be contained in the Leak Rate Test Program.
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3.3 Conclusions The TS changes proposed by the licensee are in compliance with the requirements of Option B and consistent with the guidance of Regulatory Guide 1.163, dated September 1995, with the exception of reverse direction testing, as discussed above. Despite the different format of the licensee's current TS, all of the important elements of the guidance provided in the NRC letter i
to NEI dated November 2, 1995, are included in the proposed TS. Therefore, they are acceptable to the NRC staff.
Based on the above 3.2, the licensee has provided justification that reverse direction testing, along with additional measures to ensure leak tightness of valve packing and gaskets, provide adequate assurance that the overall objectives of 10 CFR Part 50, Appendix J, will be met, and therefore, the licensee's performance based leak rate testing program is acceptable to the NRC staff.
4.0 STATE CONSULTATION
In accordance with the Comission's regulations, the New York State official was notified of the proposed issuance of the amendment. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding.(61 FR 20855). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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6.0 CONCLUSION
The Commission has concluded, based oh the considerations discussed above, l
that (1) there is reasonable assurance that the health and safety of the l
public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the comman defense and security or to the health and safety of the public.
Principal Contributor: Karen Cotton Date:
October 4,1996