05000298/LER-1985-001, :on 840922,during Secondary Containment Leak Test,Fuel Handling Operations Conducted W/O Verification of Secondary Containment Integrity.Caused by Combination of Procedural & Personnel Errors
| ML20107D375 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 02/14/1985 |
| From: | Mace E, Thomason P NEBRASKA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| CNSS850069, LER-85-001, LER-85-1, NUDOCS 8502220348 | |
| Download: ML20107D375 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| 2981985001R00 - NRC Website | |
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LICENSEE EVENT REPORT (LER)
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NAME TELEPHONE NUMSER AREA CODE E. M. Mace, Plant Engineering Supervisor 41012 81215 l-13 1811 1 I COMPLETE ONE LINE FOR EACM CORAPONENT FAILURE DGOCRISGO IN TMs3 REPOst? dist "O
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During plant shutdown conditions, a Secondary Containment Leak Test was performed to verify secondary containment integrity prior to defueling operations. This test is required by Cooper Nuclear Station Technical Specifications, paragraph 4.7.C.I.c.
Af ter completion of what was considered to be a satisfactory Secondary Containment Leak Test, the reactor core was completely defueled.
Af ter defueling operations had been completed, it was discovered that plant condi-tions had existed during the Secondary Containment Leak Test which invalidated the results. Therefore, fuel handling operations had been conducted without verification of secondary containment integrity, which is a violation of Cooper Nuclear Station Technical Specifications. This violation was caused by a combination of procedural and personnel errors, with no generic implications.
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NRC Form 308A U S NUCLE *J 5:ETULATORY COMMISSION LICENSEE EVENT REPORT (LER) TEXT CONTINUATION AreRovEo oMe No siin-cio.
EXPIRES 8/3U85 FACILITY NAME (1)
DOCKET NUMSER (28 LER NUMSER 16)
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<.-.a mc r, unew nn On September 18, 1984, during plant shutdown conditions, Surveillance Procedure 6.3.10.8, Secondary Containment Leak Test, was conducted. This test is required by CNS Technical Specification 4.7.C.1.c. in order to verify secondary containment integrity prior to fuel hcndling operations. This test failed because the required 1/4 inch of water vacuum could not be attained in secondary containment. The failure of the test was attributed to a Reactor Recirculation Motor Generator (RRMG) set ventilation exhaust valve which had been dismantled for maintenance, thus providing a secondary containment leakage path during the test. On September 20, 1984, follcwing repair work on the RRMG set ventilation exhaust valve, a second Secondary Containment Leak Test was performed with satisfactory results. On September 22, 1984, fuel handling operations were commenced and core defueling was completed on September 29, 1984.
Due to the failure of the first Secondary Containment Leak Test, a Nonconformance Report was issued to document the failure and its cause, as described above. On November 30, 1984, the CNS Quality Assurance Department completed its review of the nonconformance report and identified documentation which showed that the original evaluation was invalid (i.e., the 48 inch RRMG set ventilation exhaust valve had not been dismantled during the test). Accordingly, another investigation was initiated to determine the cause of the failure of the first test.
The resulting investigation included a review of the plant conditions which had changed between the first test and the second test. After extensive research, which included discussions with the operators involved, analysis of several Control Room recorder charts, a review of maintenance work which may have been in progress, and a review of pertinent operating logs, it was determined that (1) the mechanical vacuum pumps had assisted the SBCTS during the successful test and (2) one of the redundant SBGTS discharge lines may have been flooded with water which could have affected both tests. After an independent verification of this data, the Station Operations Review Committee convened on January 16, 1985 and determined that fuel handling operations had been conducted without verification of secondary containment integrity and that the event was reportable.
With the plant still in shutdown conditions, on February 12, 1985, after the redun-dant SBGTS discharge line had been drained and the secondary containment had been returned to the same configuration that existed on September 20, 1984, a satisfactory Secondary Containment Leak Test was performed. Based upon the results of this test, it is suspected tha..he actual cause of the failure of the first Secondary Contain-nent Leak Test was the flooded SBGTS discharge line.
Procedural and personnel errors identified which contributed to this event are:
1.
Surveillance Procedure 6.3.10.8 did not specify the exact plant conditions necessary to ensure that a valid Secondary Containment Leak Test was performed.
2.
Surveillance Procedure 6.4.8.7, "Offgas Loop Seal Blowdown and Fill", was in error, which could have allowed a water obstruction to be created in one of the redundant SBGTS discharge lines.
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NRC Form 3esA U.S. NUCLEAA KE2ULATORY COMMISSION UCENSEE EVENT REPORT (LER) TEXT CONTINUATION An RovEo ove No. am-oin EXPIRES 8/3t/85 FACILITY NAatt HD DOCKET NUMOEM (2)
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The Control Room Operators on duty at the time of the second Secondary Contain-ment Leak Test failed to recognize that existing plant conditions would not permit a valid test of secondary containment integrity.
Corrective actions taken to preclude recurrence of this event are:
1.
Surveillance Procedure 6.3.10.8 is being revised to specify the required plant conditions necessary to conduct a valid s,econdary containment integrity test.
2.
Surveillance Procedure 6.4.8.7 will be changed to preclude creating a water obstruction in the SBGTS discharge line.
3.
Training will be conducted for licensed operators on the interrelationship between various systems and plant conditions that affect the validity of testing conducted to verify secondary containment integrity.
This event had no effect on the public health and safety and has no generic inplications.
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COOPER NUCLEAR STATION Nebraska Public Power District
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CNSS850069 February 14, 1985 U. S. Nuclear Regulatory Cormiission Document Control Desk Washington, D.C.
20555
Dear Sir:
Cooper Nuclear Station Licensee Event Report 85-001 is forwarded as an attachment to this letter.
Sincerely, k-,
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p. V. Thomason f
Division Manager of Nuclear Operations PVT:lb
- Attach, cc:
R. D. Martin L. G. Kuncl J. D. Weaver L. R. Berry INPO Records Center ANI Library
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