IR 05000309/1982018
| ML20028B887 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 11/12/1982 |
| From: | Bettenhausen L, Pullani S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20028B883 | List: |
| References | |
| 50-309-82-18, NUDOCS 8212070148 | |
| Download: ML20028B887 (9) | |
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U. S. NUCLEAR REGULATORY COMMISSION
REGION I
Report No. 50-309/82-18 Docket No. 50-309 License No. DPR-36 Priority
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Category C
Licensee: Maine Yankee Atomic Power Company 83 Edison Drive
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Augusta, Maine 04336 Facility Name: Maine Yankee Atomic Power Station Inspection At: Wiscasset, Maine Inspection Conducted:
eptember 27 - October 1, 1982 T
Inspectors:
// - /2 - 81 S.~V."P0llani, Reactor Inspector date Approved by:
/M/h NN2/et L. H. Bettenhausen, Chief, Test Program date Section, Engineering Program Branch Inspection Summary:
Inspection on September 27 - October 1, 1982 (Report No.
50-309/82-18 Areas Inspected:
Routine, announced inspection of procedure review, test witnessing and results evaluation of Local Leak Rate Test (LLRT) and Integrat-
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ed Leak Rate Test (ILRT) and tours of the facility. The inspection involved 14 inspector hours in office and 47 inspector hours onsite by one region-based NRC inspector.
Results:
No violations or deviations were identified.
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DETAILS
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1.
Persons Contacted 1.1 Maine Yankee Atomic Power Company (MYAPC)
R. Arsenault, Operations Department Head
- R. Bickford, Assistant Operations Department Head
- J. Brinkler, Assistant Plant Manager P. Cereste, Instrument Supervisor C. Giggey, Performance Engineer (Test Supervisor)
J. Hebert, Director of Plant Engineering
- L. Speed, Lead Performance Engineer
- D. Sturniolo, Assistant to Plant Manager E. Tarnuzzer, Test Consultant
- E. Wood, Plant Manager 1.2 Nuclear Regulatory Commission (NRC)
- P. Swetland, Senior Resident Inspector The inspector also interviewed other licensee employees during the course of inspection.
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- denotes those present at the exit interview on October 1, 1982.
2.
Local Leak Rate Testing 2.1 References
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10 CFR 50, Appendix J, Primary Reactor Containment Leakage Testing i
for Water Cooled Power Reactors
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Maine Yankee Technical Specifications, Section 4.4, Containment Testing
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FSAR Section 5.1, Reactor Containment
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ANSI /ANS 56.8 - 1981, Containment System Leakage Testing Require-ments I
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Administrative Procedure 0-06-1, Procedure Preparation, Classifica-tion and Format, Revision 0
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Administrative Procedure 0-06-2, Procedure Review, Approval and Distribution, Revision 1
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Administrative Procedure 0-06-5, Measuring and Test Equipment, Revision 5 Administrative Procedure 0-07-3, Maintenance Requests, Revision 0
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Administrative Procedure 0-10-2, Surveillance Test and Records,
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Revision 1 2.2 Documents Reviewed
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Surveillance Procedure 3.17.4, Class B & C Leakage Testing, Revision
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Surveillance Procedure 3.17.4.2, Purge Supply Duct Leak Test, Revision 3 Record of LLRTs performed between the previous ILRT (1979) and the
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current ILRT (1982)
Selected LLRT instrumentation calibration records.
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Selected Flow Diagrams.
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Main Yankee Licensee Event Report 81-013/03 L-0 for unacceptable leakages for containment isolation values 2.3 Scope of Review The inspector reviewed the above documents to ascertain that the licens-
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ee's LLRT program was conducted in compliance wi;h the regulatory re-
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quirements and licensee commitments referenced fn Section 2.1.
The inspector also witnessed selected LLRT activities.
Further details and inspection findings are described below.
2.4 Test Witnessing On September 28, 1982, the inspector witnessed portions of a Type C LLRT for Containment Purge Supply Duct Isolation Valves VP-A-1 and 2.
The test was being conducted in accordance with approved procedure 3.17.4.2, Purge Supply Duct Leak Test, Revision 3.
The test volume between the two valves was pressurized to approximately 50 psig and the leakage rate was estimated by noting the pressure decay over a period of time. The estimated leakage was 138.42 lbm per day, whereas the administrative leakage iimit for this penetration was 10 lbm per day. The licensee estimated and found the running total of Type B and C test results at this time did not exceed the TS limit of 0.6La, 377 lbm per day. How-ever, having exceeded the administrative limit, the licensee performed certain additional tests and determined that the gross leakage was through the upstream valve VP-A-1.
After certain maintenance was done on this valve, the leakage testing was repeated. The calculated leakage was then 7.87 lbm per day, which was below the administrative limit.
The inspector observed the performance of the test to ascertain that prerequisites were met, proper precautions were taken, measuring and test equipment was properly calibrated, test was conducted in accordance with
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the procedure, test crew actions were correct and timely, and the re-quired data was recorded.
2.5 Test Results Evaluation The inspector reviewed, on a sampling basis, the results of LLRTs per-formed between the previous ILRT (1979) and the current ILRT (1982) to verify conformance with the requirements of 10 CFR 50, Appendix J, and Technical Specifications.
2.5.1 Recording of Summary Type B and C Test Results The inspector stated the licensee's current practice of erasing the previous test result from the summary Type B and C test results log and entering the new test result when a new test is performed on a penetration is unacceptable. The practice makes it difficult to trace the history of various tests performed on any specific pene-tration, including AS FOUND and AS LEFT test results before and after any repairs or adjustments are made to the penetration. The licensee agreed to revise the practice to show all the test results in chronological order for each penetration including the AS FOUND and AS LEFT results. This is an Inspector Followup Item (50-309/82-18-01).
2.5.2 Reporting of Instrument Error Analysis As of the date of the inspection, the licensee had not performed any instrumentation error analysis for Type B or C test results.
Based on the large margin between Type B and C test results and the acceptance criteria and a preliminary estimate of the instrument errors by the inspector, he made a preliminary determination that the Type B and C test results appear to be satisfactory. However, 10 CFR 50, Appendix J, Paragraph V.B.3, requires that an instrument error analysis be included in the Summary Technical Report submitted to the Commission. The licensee agreed to comply with this require-ment. This is an Inspector Followup Item (50-309/82-18-02).
2.6 Repairs and Adjustments to Containment Boundary The inspector discussed with the licensee the relationship between the improvements made to the containment boundary as a result of repairs and adjustments (RA's) and Type A test failures.
If RA's, as a result of the Type B and C testing program or other reasons, are made prior to Type A test sequence, the difference between AS FOUND and AS LEFT Type B and C results of the affected leakage paths should be added to the Type A test results to arrive at the AS FOUND Type A test results. A periodic Type A test should be called a " failure" if the AS FOUND Type A test results exceed 0.75 La for a test conducted at Pa, the peak accident pressure.
For periodic Type A tests conducted at reduced test pressure Pt, as is the case at Maine Yankee, the equivalent limit is 0.75 Lt.
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The inspector did not identify any unacceptable conditions, except as described above.
3.
Integrated Leak Rate Testing 3.1 General During September 28 through October 1, 1982, Maine Yankee Atomic Power Station performed a periodic ILRT as required by 10 CFR 50, Appendix J.
The test was performed in accordance with approved procedure 3.17.1, Class A Integrated Containment Leak Rate Test, Revision 3.
The inspector reviewed the procedure and witnessed preparations and various portions of the test. Details and inspection findings are described below.
3.2 Procedure Review The inspector reviewed Test Procedure 3.17.1, Class A Integrated Contain-ment Leak Rate Test, Revision 3, for technical adequacy and compliance with references in Section 2.1.
The inspector had following comments:
3.2.1 Page 3, Referer.ces The procedure references old industry standards ANSI N45.4-1972 and ANSI N274-1974 instead of new standard ANSI /ANS-56.8-1981 on con-tainment testing requirements.
Even though the licensee is not required to adopt the new standard, its use is highly recommended as the best available industry standard on containment testing.
3.2.2 Page 15, Procedure Step 5.1.1, Temperature Stabilization Criteria The description and the formula for temperature stabilization criterion as given in Step 5.1.1 did not agree each other. The criterion was also different from that given in ANSI /ANS-56.8-1981, Paragraph 5.3.1.3.
3.2.3 Page 24, Attachment A, Derivation of Formula for Leak Rate Page 1 of the procedure states that Mass Point Method is used to determine the Leak rate; however, the formulas for leak rate, as shown on Page 24, were different from that derived in ANSI /ANS-56.8-1981, Appendix B, for the same method. Also, the formulas for dispersion index and confidence limit, as given on Page 24, do not appear to be correct.
3.2.4 Liquid Level Monitoring There should be provisions in the procedure for monitoring the liquid levels in the containment that can be expected to vary and, therefore, change the containment free volume which is assumed to be a constant in the leak rate equation.
In addition to changes in levels of pressurizer, containment sumps, and other containment
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tanks, the reactnr water makeup during the test may also have a potential to change the containment free volume.
There should be provision to calculate the effect of these changes on the final leak rate.
3.2.5 Correction for Type A Test Results There should be provisions in the procedure for making correction to the preliminary Type A test results for systems not in proper lineup during the test. Depending on the resolution of unresolved items "
Paragraphs 3.5 and 3.6 of this report, the closed loop systems inside the containment which are not vented and drained or containment liner weld channels not vented may also have contributions to this correction.
The licensee agreed to resolve the above comments in the next revision of the procedure.
This is an Inspector Followup Item (50-309/82-18-03).
3.3 Computer Program Review The inspector reviewed portions of the program on a sampling basis to ascertain that the mathematical formulas used in the program corresponded to those given in the test procedure.
3.4 Test Instrument System The inspector reviewed the calibration records for the instrument system used for the ILRT to ascertain that the accuracy requirements were met and the calibration was traceable to the National Bureau of Standards.
The inspector also observed the operations of the automatic data col-lection system during conduct of the test.
3.5 Venting and Draining of Closed Systems
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10 CFR 50, Appendix J, Paragraph III.A.1.(d), states, in part, that those l
portions of the fluid systems that are part of the reactor coolant
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pressure boundary (RCPB) and are open directly to the containment atmo-sphere under post-accident conditions and become an extension of the boundary of the containment shall be opened or vented to the containment atmosphere prior to and during the test. Test Procedure 3.17.1, Revision 3, did not contain this provision.
However, prior to the start of the test, the licensee initiated Procedure Change Request 82-320 to include l
this provision in the procedure.
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10 CFR 50, Appendix J, Paragraph III.A.I.(d) further states that (with certain exceptions given therein) portions of closed systems inside
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containment that penetrate containment and rupture as a result of loss of
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coolant accident shall be vented to the containment atmosphere; and that i
all vented systems shall be drained of water or other fluids to the
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extent necessary to assure exposure of the system containment isolation valves to containment air test pressure and to assure they will be I
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subjected to post-accident differential pressure.
Prior to the start of the test, the inspector brought these requirements to the attention of the licensee. The licensee stated that it is not practical to implement these requirements for the current test as it requires a thorough analy-sis of the affected systems and may require several plant modifications to make provisions for venting and draining.
For the current Type A test, the licensee chose not to vent and drain but to perform a Type C test for each affected penetration and add the Type C test results to the Type A test result.
For all future Type A test, the licensee later (during the exit meeting) made a commitment to complete the required analysis and necessary plant modifications to comply with the above requirements of Appendix J before the end of calendar year 1983 or submit Appendix J exemption request within the same period. The inspector further discussed the details of these requirements with the licensee and gave the licensee a copy of the NRC Memorandum, E. L. Jordan to R. C.
Lewis, August 24, 1981, for additional guidance on the subject.
This is an Unresolved Item pending the required actions by the licensee (50/309/82-18-04).
3.6 Venting of Containment Liner Weld Channels The objective of ILRT is to assess the containment leakage rate while the containment is in a state as close as practical to that which would exist following a postulated design basis accident. As the weld channels at Maine Yankee are not designed to the same criteria as that of the liner, the integrity of the weld channels against leakage may not be adequate if they are exposed to the loading conditions associated with a postulated accident.
Further, if the weld channels are not vented during the ILRT, any potential leakage paths existing in the liner weld seams would go undetected.
For these reasons, the weld channels should be vented during the ILRT. The inspector gave the licensee copies of two NRC memorandums l
on the subject:
(1) G. C. Lainas to W. R. Butler, December 15, 1977, and (2) R. L. Baer to E. J. Brunner, July 30, 1981.
l Prior to the start of the ILRT, the inspector had discussed the a>'ve subject with the licensee. However, the licensee chose not to ve, the weld channels during the ILRT, apparently due to potential delays it may cause for the test. As of the last day of inspection, the licensee had not furnished a technically valid reason for not venting the weld chan-nels. The inspector made it clear to the licensee that the validity of the current and all future ILRTs will be subject to a satisfactory
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resolution of this problem. During the exit meeting the licensee made a commitment to analyse and resolve the problem before the end of calendar l
year 1983.
This is an Unresolved Item pending further actions by the j
licensee and review of those actions by the NRC (50-309/82-18-05).
3.7 Containment Inspection and Test Boundary Verification The inspector conducted several tourt independently and with licensee personnel both before and during I;M. During these tours, the contain-ment was inspected for existence of artificial boundaries, the valve lineups were verified on a sampling basis to be in accordance with the i
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test procedure, and the test boundaries were surveyed for evidence of leakage.
3.8 ILRT Chronology September 28, 2220 Completed containment inspection.
2330 Started pressurization of containment.
September 29, 0125 Containment pressure at 5 psig; Containment Isolation Signal (CIS) occurred as expected.
0135 Stopped pressurization.
0310 Containment entry made for approximately 30 minutes of inspection at 5 psig 0940 Containment personnel hatch leak test completed.
0950 Continued pressurization to 23 psig.
1655 Pressurization line isolated.
1900 Reduced Primary Component Cooling (PCC) flow to 6 containment coolers for containment air temperature stabilization.
2100 Temperature stabilization achieved; started 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> ILRT September 30, 1000 Appear to have greater than allowed leakage as read from the computer output.
Leak search conducted; no major leaks identified.
Problem identified as due to largely staggered output from the wide range pressure instrument; decided to use the output from narrow range pressure instrument for leakage calculations.
2100 ILRT Completed; 95% Upper Confidence Limit (UCL) of leakage is 0.0346 Versus the acceptance criteria of 0.0521 wt. %/ day.
October 1, 0221 Started verification test.
0600 Started depressurization of containment after the test is completed.
3.9 Preliminary ILRT Results Evaluation The licensee evaluated the preliminary ILRT results for the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period starting 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br /> on September 29, 1982 and ending 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br /> on September 30, 1982. The calculated leakage at 95% UCL was 0.0346 weight
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percent per day. The test acceptance criteria is 0.0521 weight percent per day. The inspector stated that the following modifications should be done to the above calculated leakage value before it is reported to the Commission:
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Corrections for changes in free containment air volume during the test as explained in Section 3.2, Comment 4 on the test procedure.
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Corrections for systems not in proper lineup during the test as explained in Section 3.2, Comment 5 on the test procedure. This should include steam Generator-3 Blowdown Trip Valve BD-T-32, and Leak Monitoring Isolation Valves LM-A-43 and 45 which were not in proper lineup.
3.
As of the date of inspection, the licensee had not performed any instrumentation error analysis for the ILRT results.
10 CFR 50, Appendix J, Paragraph V.B.3, requires that an instrument error analysis to be included in the Summary Technical Report submitted to the commission.
The licensee agreed to make the above modifications before the results are reported in the Summary Techr' cal Report.
This is an Inspector Followup Item (50-309/82-18-06).
The inspector also made it clear to the licensee that the validity of the current ILRT would further be subjected to satisfactory resolution of issues explained in Sections 3.5 and 3.6 of this report.
4.
Unresolved Items Unresolved items are macters about which more information is required to ascertain whether they are acceptable, or whether they are violations or deviations.
Paragraphs 3.5 and 3.6 contain unresolved items.
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5.
Plant Tours l
The inspector made several tours of the plant, including Containment, l
Turbine Building, Primary Auxiliary Building, and Control Room. During these tours, the inspector observed operations and activities in pro-
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gress, general condition of the safety related equipment, component tagging, and system operations to support ILRT.
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Exit Interview The inspector met with licensee management representatives (see Section I
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for attendees) on October 1, 1982. The inspector summarized the scope and findings of the inspections at this time.
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