IR 05000298/1990004
| ML20034C056 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 04/19/1990 |
| From: | Constable G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20034C055 | List: |
| References | |
| 50-298-90-04, 50-298-90-4, NUDOCS 9005020016 | |
| Download: ML20034C056 (6) | |
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APPENDIX U.S. NUCLEAR REGULATORY COMMIS$10N
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REGION IV
NRC Inspection Report:
50-298/90-04 Operatingbcense:
DPR-46 j
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Docket: 50-298
Licensee:
Nebraska Public Power District (NPPD)
P.O. Box 499 i
Columbus, Nebraska 6860'-0499
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Facility Name:
Cooper Nuclear Station (CNS)
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inspection At: CNS, Nemaha County, Nebraska l
Inspection Conducted:
February 16 through March 15, 1990 Inspectors:
G. A. Pick, Resident Inspector, Project Section C Division of Reactor Projects
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W. R. Bennett, Senior Resident inspector, Project Section C
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Division of Reactor Projects i
Approved:
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G. L. constanie, Uniet, Project section c urte '
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DivisionofReactorProjects
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Inspection Summary Inspection Conducted February 16 through March 15, 1990 (Report 50-298/90-04)
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Areas inspected:
Routine, unannounced inspection of operational safety verification, monthly surveillance observations, monthly maintenance observations, and refueling activities.
Results: The licensee commenced the refueling outage for Cycle 13 on March 5,
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1990, contractor performance appears to indicate better training of contractors.
than was apparent in previous refueling outages. The licensee demonstrated
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responsiveness to an NRC Infonnation Notice which could affect maintenance of secondary containment. No violations or deviations were identified in this inspection.
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9005020016 900420 FDR ADOCK 05000298
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DETAILS
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1.
persons Contacted
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l principal Licensee Employees
- G. R. Horn, Division Manager of Nuclear Operations i
J. M. Meacham, Senior Manager of Operations
- S. M. Peterson,_ Senior Manager of Technical Support Services i
- R. Brungardt, Operations Manager
- R. L. Gardner Maintenance Manager
- J. V. Sayer, Radiological Manager i
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- H. T. Hitch, Plant Services Manager
'J. Flaherty, Engineering Manager
- R. A. Jansky, Outage and Modifications Manager i
D. W. Bremer, Operations Support Group Supervisor
- L. E. Bray, Regulatory Compliance Specialist l
- Denotes those present during the exit interview conducted on March 19, 1990.
The NRC inspectors also interviewed other licensee employees and contractors during the inspection period.
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2.
plant Status
The end of fuel cycle power coastdown continued this inspection period.
The nexinom achievable full power decreased, due to fuel burnup, from 92 percent on February 15, 1990, to 90 percent on March 2, 1990. The plant was manually scramned on March 3, after power had been decreased, in
preparation for the Cycle 13 refueling outage. Defueling was conpleted on March 15.
3.
Operational Safety ~ Verification (71707)
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The inspectors observed plant shutdown activities on March 2 and 3, 1990.
The operators began decreasing power, in. increments, at 12:03 p.m. by
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t reducing recirculation pump flow. After reaching minimum recirculation-
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flow, power was further decreased by. rod insertion. - The operators manually scrammed the reactor from 17 percent power, at I a.m. on March 3
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1990.
Following the manual scram, the reactor water level reached -
11.5 inches. The group isolation and reactor scram low level setpoints are set at 12.5 inches. Group isolations occurred in reactor water l
cleanup (RWCU), shutdown cooling, and secondary containment ventilation isolations along with an automatic scram signal. The water level shrink occurred due to void collapse on the the sudden loss of heat energy. The operators recovered level immediately and reset the group isolations.
Low level isolations have been a recurring problem at CNS following manual scrams. ~ The licensee previously changed the shutdown procedure to require
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increasing reactor vessel level to 45-50 inches prior to a r>anual scram in an attempt to prevent low level isolations. Prior to the manual scram.
the reactor operators raised reactor vessel level to approximately j
46 inches and transferred the feedwater flow contml from the feedwater j
discharge valves to the startup valves.
This was an attempt to prevent
the void collapse and subsequent level shrink from causing a reactor i
scram signal and group isolation; however, these measures did not I
alleviate the problem. The licensee has had General Electric perfom an
analysis to determine the feasibility of lowering the scram and isolation setpoint to prevent unnecessary isolations and scram signals.
Proposed Technical Specification (TS) Change No. 79 is in the licensee review process to lower these setpoints.
l After the reactor was shut.down, another RWCU isolation occurred on high l
flow. A high flow condition did not exist but had been sensed due to
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flashing of the coolant at the pump suction and in the flow sensor. The e
coolant flashed to steam when coolant temperature and pressure reached a
saturation conditions. During this outage, the licensee will implement Design Change 89-256 which will increase coolant subcooling in t1e RWCU t
suction and should eliminate this problem.
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The inspectors verified that selected activities of the licensee's radiological protection program were implemented in conformance with facility policies, procedures, and regulatory requirements.
Radiation and contaminated areas were properly posted and controlled.
Surveys were -
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performed during and after the reactor shutdown to verify proper
radiation area postings. Postings were modified as required. The
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licensee, during this inspection period, made a concerted effort to
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reduce the number of contaminated areas in the plant.
Improvement was noted by the inspectors, especially in the radwaste building. The effort
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to reduce the number of contaminated areas is planned to continue through the outage. Radiation work permits were properly processed and contained
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appropriate infomation to ensure that work could be performed in a safe i
and controlled manner.
Contractor personnel were observed to be using
good radiological control practices possibly due to specific training-i given prior to the start of the outage.
Radiation monitors were properly used to check for contamination.
.j During review of NRC morning reports, the inspector noted that two
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similar plants reported that they discovered it was possible to operate
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in an unanalyzed condition.
Following a reactor scram, the plants
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specified that procedures required placing the mode switch in shutdown,
which bypassed the automatic low pressure closure of the main steam.
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isolation valves (MSIVs). The inspector discussed these reports with licensee personnel who demonstrated that this was not a concern at CNS i
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because the MSIV closure is not bypassed with the mode switch in the
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shutdown position. The licensee informed the inspector that these events
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had been previously discussed at a BWR Owner's Group Emergency Operating
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Procedures meeting, j
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The inspectors observed security personnel perfonn their duties of vehicle, personnel, and package search. During this inspection period, i
the inspectors noted improvement by contractor personnel in knowledge of
licensee security procedures. The security department processed
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approximately 600 badges with minimal problems noted. Site tours were
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conducted by the inspectors to ensure that compensatory measures were
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properly implemented as required. The protected arec barrier had adequate illumination.
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No violations or deviations were identified in this area.- Control of
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plant operations during the shutdown was proper and conservative.
Training of plant contractors appears to have improved compared to the last refueling outage.
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4.
Monthly Surveillance Observations (61726)
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The inspector observed three local leak rate tests (LLRT) during the period March 5-9, 1990:
l Core Spray (CS)-MOV-11A ard CS-MOV-12A CS outboard and inboard
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injection valves
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Residual Heat Removal (RHR)-MOV-21B Loop B drain to the torus
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RHR-MOV-26B and RHR-MOV-318 RHR Loop B drywell spray line isolation
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valves
The tests were perfonied in accordance with Surveillance
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Procedure (SP) 6.3.1.1, " Primary Containment Local Leak Rate Tests,"
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l Revision 26, 1989. The personnel performing the test utilized a test rig (
containing calibrated instruments which included a pressure gauge, flow meters, and a pyrometer. The personnel followed proper radiological practices preventing the spread of contamination. The licensee uses two
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methods, makeup flow and pressure decay, to determine local leak rates.
Initially, the licensee attempts to measure the leak rate using the makeup
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flow method since the test data is more accurate and obtained faster.
However, for undetectable leakage the pressure decay method is used. The personnel properly connected the test rig. A station operator pressurized the test volumes with air and drained the test volume prior to start of the test to eliminate entrapped water which could affect test data.
After pressurizing the test volume, the licensee perforned a soap bubble test to check for air leaks around the flanges and valve bonnets.
i The inspector reviewed SP 6.3.10.8, " Secondary Containment Leak Test,"
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Revision 13, dated October 5,1989, which was performed on March 5,1990.
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The test was performed to verify secondary containment integrity prior to
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l performing core alterations, as required by TS. The inspector verified
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that all prerequisites and applicable steps of the procedure were documented, and that results met TS acceptance criteria.
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Prior t'o performance of this test, the inspector discusse'd with the licensee the impact of NRC Information Notice No. 90-02, " Potential Degradation of Secondary Containment." The licensee demonstrated to the inspector that they had adequately reviewed the information notice and that it did not affect CNS.
No violations or deviations were identified in this area.
The licensee demonstrated good communications among departments during perfomance of surveillances. The licensee adequately reviewed an NRC-Infomation Notice prior to perfoming a test which could have been affected by the notice.
5.
Monthly Maintenance Observation (62703)
On March 6,1990, the inspector observed electricians meggering a control cable for the condensate inlet valve to Steam det Air Ejector A.
All resistance values measured indicated no breakdown in the cable insulation.
The breaker was properly tagged out using Clearance Order 90-193. The meggering was conducted on 12 randomly selected balance-of-plant control and power cables which run through the heater bay. This activity was performed to check for indication of insulation degradation. Previously, the licensee had to replace cables which had become embrittled due to being routed too close to a main steam line.
On March 7,1990, the inspector observed electricians disconnect motor leads to CS Test Line Valve CS-MOV-2SB motor operator. The electricians used Maintenance Procedure (MP) 7.3.33 " Electrically Disconnecting and Connecting Limitorque Valve Operators," Revision 5, dated January 11, 1990, to disconnect the leads.
The electricians removed the motor operator in preparation for valve body thickness measurements and generated a disconnection /reconnection diagram as they removed the numbered leads.
On March 12, 1990, the inspector observed the diesel. generator vendor technical representative and a mechanic conduct a boroscopic examination of cylinder intake and exhaust valves.
Their examination determined that all valves were in good condition, had minimal wear, and had minimal carbon deposits. The plant chemist checked the service water side of the jacket water heat exchanger for microbiological corrosion.
No violations or deviations were identified in this area.
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Refueling Activities (60710)
On March 8,1990, prior to fuel handling, the inspector. observed licensed operators perform SP 6.1.27.4, " Refueling Interlocks. Functional Test,"
Revision 0, dated February 20, 1989.
This procedure tests the refueling interlocks between the reactor manual control system and the refueling platform as required by TS. The procedure prerequisites were completed prior to performance of the procedure.
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During the period March 5-8, 1990, the inspectors observed, in part, the disassen61y of the reactor vessel in preparation for defueling. The
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inspector observed transfer of the drywell head and steam separator bolt detensioning. The lead mechanic utilized the procedure, controlled the j
work activities, and remained cognizant of upcoming disassembly
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evolutions.
The inspectors observed several operator crews perform the spiral off-load of the core during the period March 9-15, 1990.
Each crew
performed the offload in accordance with applicable procedures and maintained required communications. The offload was performed with no
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major problems.
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During all fuel bundle transfers from the reactor vessel to the spent i
fuel pool, reactor engineers independently verified the proper refuel
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procedure step conduct, proper transfer locations, and bundle set L41 number.
No violations or deviations were identified in this area.
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t 7.
Exit Interviews (30703)
An exit interview was conducted on March 19, 1990, with licensee representatives identified in paragraph 1.
During the interview, the NRC inspectors reviewed the scope and findings of the inspection. Other meetings between the inspectors and licensee management were held periodically during the inspection period to discuss identified concerns.
The licensee did not identify as proprietary any information provided to, or reviewed by, the NRC inspectors.
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