IR 05000341/1992019
| ML20034F408 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 02/25/1993 |
| From: | Burgess B, Nejfelt G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20034F406 | List: |
| References | |
| 50-341-92-19, NUDOCS 9303030106 | |
| Download: ML20034F408 (5) | |
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NUCLEAR REGULATORY COMMISSION
REGION III
Report No. 50-341/92019(DRS)
Docket No. 50-341 License No. NPF-43 Licensee:
The Detroit Edison Company 6400 North Dixie Highway Newport, MI 48166 Facility Name:
Fermi 2 Nuclear Power Station Inspectisn At:
Fermi Site, Newport, MI Inspection Conducted:
October 27, 1992, through February 24, 1993 d#/f/93 Inspector:
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A
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Nejfeg Da'te G'.
M.
d+/ar/[3 Approved By:
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B. L. ~ Burgep's, Chief Date Operational Programs Section Inspection Summary Inspection conducted onsite October 27-30, 1992.
Data analysis a
completed in-office on February 24, 1993 (Report No.
50-341/92019(DRS)).
Announced inspection'of the licensee's Containment Integrated Leak Rate Test (CILRT), utilizing NRC Manual Chapters 35702 (quality verification), 70307 (review),
70313 (observation), and 70323 (analysis).
Results: Excessive as-found containment isolation valve local leak rates, prior to the October 1992 CILRT, resulted'in the second consecutive. administrative Fermi CILRT failure.(Paragraph 2).
After valve adjustment and repairs, the licensee performed the CILRT.
The engineers and technicians worked effectively and closely monitored the test (Paragraph 4).
The collected and reviewed CILRT data successfully demonstrated that containment leakage was well below regulatory requirements (Paragraph.5).
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a 9303030106 930225 PDR ADOCK 05000341 G
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DETAILS
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1.
Persons Contacted
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The Detroit Edison Company (DECol W.
Orser, Senior Vice President D.
Gipson, Vice President, Nuclear Operations R.
McKeon, Plant Manager R.
Stafford, General Director, Nuclear Assurance
+ B.
Sheffel, General Supervisor, Inservice Inspection
+ S.
Hare, CILRT Test Lead U.
S.
Nuclear Reculatory Commission (NRC)
S.
Stasek, Senior Resident Inspector F.
Brush, Resident Inspector All of the above individuals attended the onsite pre-exit interview conducted October 30, 1992.
+ Denotes those participating in the telephone exit on February 24, 1993.
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2.
Local Leak Rate Testina History (70307)
The October 1992 CILRT represented the second consecutive administrative failure.
The administrative failure was due to the cumulative as-found leakage from completed local leak.
rate tests (LLRT) of containment isolation valves exceeding
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the 0.75% limit specified by 10 CFR 50, Appendix J,.
Criterion III (See Licensee's Event Report No.'50-341/92-007 dated September 13, 1992).
The first CILRT-administrative failure occurred in 1989 because of-excessive leakage through the. main steam isolation valves.
The number of 1992 LLRT valve failures represented an appropriately 35 percent reduction'in the number of LLRT valve failures found before the 1989 CILRT.
The licensee-i attributed this improvement to the installation of modifications to replace problematic valves, and the improved ~ training provided to maintenance personnel prior to performing valve work, a
No violations of NRC requirements'werefidentified.
3.
Containment Intecrated Leak Rate Test Procedure Review (70307)
Prior to the performance of the CILRT, the111censee properly established needed system lineups using CILRT Procedure
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43.401.100, Revision.22.
For example, the torus drywell
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vacuum breakers were blocked open to prevent artificial
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leakage barriers and a detailed containment inspection of the drywell was completed.
Components not designed to withstand test pressure, such as fire extinguishers and light bulbs, were removed for protection.
The' inspector verified that pipe caps were removed and.ILRT tags hung for several accessible vent' paths.
Examples included the high.
pressure core injection steam supply vent valve and a drywell purge vent valve.
The location of these vents was facilitated by the distinctive tags identifying LLRT boundaries and valves.
The inspector reviewed the Certificate of Calibration for humidity detectors and calibration records for selected CILRT pressure gauges and rotameters.
This review included verification that the instrumentation calibration range was traceable to a recognized industry standard, that the calibration due date had not expired, and that functional checks were made of test equipment after installation and prior to pressurization.
CILRT instrumentation included four humidity detectors in the torus and eight in the drywell.
Also, 26 resistive thermocouple' detectors (RTDs)
were used in 20 containment zones.
The CILRT procedure provided the containment locations of required instrumentation.
The inspector reviewed documentation to support the placement of calibrated instrumentation inside containment.
No discrepancies were identified.
Prior to the start of containment pressurization, the CILRT director briefed control room personnel on the various methods for venting the containment.
Each shift, the oncoming operations crew reviewed the preferred containment vent path method during the CILRT.
In an emergency, such as a fire inside containment, the control room operators knew
that the newly installed unfiltered harden vent could be i
used.
To minimize the likelihood of an inadvertent and unmonitored release from the containment, an administrative control was placed on the use of the harden vent, requiring the permission of the Radiation Protection Superintendent.
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No violations of NRC requirements were identified.
4.
Containment Intearated Leak Rate Test Witnessina (70313)
The inspector observed the CILRT on October-27.and 28, 1992.
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Test personnel complied with surveillance procedure
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H 43.401.100, Revision-22, regarding the stabilization and l
verification of air flow.
Technicians _ recorded data at 10.
minute intervals and toured containment boundaries hourly.
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The containment was pressurized to approximately 59 psig at the commencement of the test.
During the CILRT, the inspector surveyed the containment boundary to spot-check the test lineup.
The inspector found no lineup
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discrepancies.
Prior to depressurizing the containment, the venting path was verified.
This verification found excessive leakage past T46-F407, a standby gas treatment system air operated butterfly valve.
The licensee avoided potential reactor building ventilation system overpressurization by cycling the noncontainment valve, T46-F407, fully closed.
The inspector observed that the procedure to-verify the containment vent path contained sufficient information to prevent damage to the reactor building ventilation system in the event that a rapid depressurization of containment was needed.
- No violations of NRC requirements were identified.
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Test Result Evaluation (70323)
The 1992 Fermi 2 Nuclear Power Station CILRT was successful.
The BN-TOP-1 time analysis method demonstrated that containment leakage was less than the maximum allowable containment leakage of 0.5 weight percent per day at a peak
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accident pressure of 59.5 psig.
The. measured and corrected 24-hour containment leakage was 0.170% p/ day with an upper 95% confidence of 0.217.% p/ day.
The inspector independently verified that the BN-TOP-1 termination criteria were satisfied for a successful test.
No violations of NRC requirements were identified.
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Ouality Assurance Program Involvement to Ensure Containment Intecrity (35702)
The inspector reviewed Inservice Inspection'and. Performance.
Evaluation Program, ISI/ PEP, RF-02, Summary Report, of July 26, 1991, Appendix B.
The report attributed improved LLRT performance to the replacement of. valves with a history of leakage, and the improved training provided to maintenance personnel prior to performing valve work.
The audit demonstrated a. steady decrease in the number of outage valve failures in outage 88-01, refueling outage (RF). -01, and RF-02.
Comparing the results from the 1992 CILRT.with those for the 1990 CILRT,-the containment integrity' improved approximately 25% using-the most conservative containment'
leakage rates.
No violations of NRC requirements were identified.
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7.
Exit Interview
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The inspector met with licensee representatives (denoted in Paragraph 1) on October 30, 1992.
Following review of all data submitted by the licensee, an exit interview was conducted by telephone on February 24, 1993. The inspector summarized the scope and findings of the inspection activities.
The licensee acknowledged the inspection findings and that with two consecutive CILRT administrative failures, it was necessary to either perform an CILRT next outage or pursue an exemption.
The inspector also discussed the likely informational content of the inspection report with regard to documents or processes reviewed by the inspector during the inspection.
The licensee did not identify any such document / processes as proprietary.
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