ML20247E207
| ML20247E207 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 07/19/1989 |
| From: | Trevors G NEBRASKA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| CNSS890371, NUDOCS 8907260116 | |
| Download: ML20247E207 (4) | |
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CQdPER NUCLEAR ST ATION Nebraska Public Power District
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e CNSS890371 July 19, 1989 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 205.5 Lubj ect: NpFD Response NRC Inspection Report No. 50-298/89-18 Gentlemen:
This letter is written in respouse to your letter dated June 22, 1989, transmitting Inspection Report No. 50-298/89-18.
Therein you indicated that certain of our activities were in violation of NRC requirements.
Following is the statement of each violation and our response in accordance with 10CFR2.201.
Statement Of Violation Failure to Follow a Safety Procedure 10 CFR Part 50, Appendix B, Criterion V, states, in part, that
" Activities affecting quality shall be prescribed by documented I
instructions, procedures or drawings, of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, or drawing."
CNS Procedure 0.9, " Equipment Cle97ance and Release Orders", Revision 7, dated February 23, 1989, specifies that the clearance order procedure provide a means of safely isolating equipment for repairs.
Contrary to the above, on May 18, 198?, the NRC inspector found Main Steam Line Drain Outboard Isolution Valve MS-M0-77 shut while danger-tagged open by Clearance Order 89-442.
In addition. Clearance Order 89-827 ut ilized one tag to isolate seven valves for performance of maintenance.
This is a Severity Level IV violation.
(Supplement 1)(298/8918-01)
Reason For Violation l
Main Steam Line Drain Outboard Isolation Valve MS-MO-77 was opened and the control switch danger tagged per CNS Procedura 0.9, " Equipment Clearance And Releasa Orders", to provide for water drainage from the Main Steam Isolation Valve (MSIV) cavity during performance of Equipment Specification Change (ESC)
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89-122.
ESC 89-122 was being implemented to upgrade the Main Steam Isolation 8907260116 890719 i\\
PDR ADOCK 05000298 Q
PDC a
U. S. Nuclear Regulatory Commission
. July 19. 1989 Page 2 LValve stem and disc on Main Steam Lines B, C. and.D.
A Croup I primary containa nt isolation signal caused MS-M0-77 to close which was contrary to the desired position per the Equipment Clearance and Release Order t
(CO.89-442). The identified weakness in our clearance order procedure was
'that it.did not provide adequate instruction for isolating equipment which received automatic isolation signals where personnel safety was not the primary concern.
Several Clearance Orders, including Clearance Order 89-827, were issued to isolate individual Control Rod Drive (CRD) Hydraulic Control Units (HCU) during the refueling outage for maintenance. Only one danger tag was hung per HCU to address that all the necessary valves to isolate the HCU were closed for the maintenance activities. Although System Operating Procedure 2.2.8,
" Control Rod Drive System", specifies the proper sequence to isolate the HCU and was used to tag out the HCU, it did not provide the level of safety necessary to ensure the valves remained isolated while the maintenance activities progressed.
Correctfve Steps Which Have Been Taken And The Results Achieved An additional danger tag was added to CO 89-442 to de-energize the. power.
supply to MS-MO-77 with the valve in the Open position. A Temporary Procedure Change to 0.9, " Equipment Clearance And Release Orders", was immediately initiated that instructed Operations personnel to tag out the motive force to equipment, in addition to its control switch, to prevent automatic repositioning of the equipment by an automatic initiating signal.
The Clearance Orders on the HCUs were released and the UCUs returned to proper valve lineup per System Operating Procedure 2.2.8, since the maintenance activieles had been cocpleted.
Corrective Steps Which Will Be Taken To Avoid Further Violations A permanent procedure change to CNS Procedure 0.9 was initiated and approved by the Station Operations Review Committee on June 8, 1989. The procedure change implemented the following additional instruction:
"Any component that can be automatically positioned or started and is operated by some motive force (electric, air, etc.) should have, in addition to its control switch, its breaker or air supply, etc., tagged in the position to preclude operation
.of the component by an init1ation signal."
A procedure change to System Operating Procedure 2.2.8 was initiated and is currently in routing for approval by the Station Operations Review Committee.
The procedure has been revised to only allow the isolation of a HCU for operational purposes utilizing one danger tag.
A note has also been added to 4
the procedure to require all associated valves be tagged if maintenance is to
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be performed.
Date When Full Compliance Will Be Achieved j
l Full compliance will be achieved by August 17, 1989.
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U. S. Nuclear Regulatory Commission y
July 19, 1969 Page 3 State Of Violation Inoperable Reactivity Control System Technical Specifications 3.4.b.1 allows continued operation for only 7 days.when a redundant component in the standby liquid control system is inoperable.
Contrary to the above, the Squib Valve A, a redundant component, was made inoperable on May 15, 1988, and remained inoperable until May of 1989.
The reactor operated in all Modes during that period.
This is a Severity Level IV violation.
(Supplement I)(298/8918-02)
Reason For'The Violation The reason for the violation was 1) inadequate instructions in the design changes package, 2) failure of craftsmen to follow the instructions in the design change, and 3) lack of training associated with squib valves.
A review of the design change has shown the instructions were vague, since they only required the squib valve to be " electrically disarmed" without specifying how it was to be accomplished.
The intent was to have the primer chamber disconnected from the firing circuit, thereby " disarming" the valve.
The design change also instructed the craftsmen to review the precautions in the squib valve vendor manual, which specifically states that shorting the connector pins with copper wire has proven to be an unsafe practice.. What actually occurred was that 1) the primer chamber was electrically disconnected from the firing circuit, and 2) the copper wire'was wrapped around the connector pins to disarm the primer chamber prior to its removal from the system.
Therefore, the design change instructions were not adequate and the vendor manual precautions were not adequately reviewed by the craftsmen, as specified.
Corrective Steps Which Have Been Taken And The Results Achieved Upon determining that the "A" Squib Valve had not fired, the surveillance procedure for "B" Loop was successfully~ completed, including the firing of the "B" Squib Valve. Following the investigation into the cause of the failure, the shorting wire'was removed from the "A" Squib Valve pins and the connector reinstalled. The "A" Standby Liquid Control Loop was then tested satisfactorily. Both squib valves were subsequently replaced and firing circuit resistance checks were made in accordance with a Temporary Procedure C'.ange to Maintenance Procedure 7.2.25, " Standby Liquid Control System Explosive (Squib) Valve Insert Replacement", to confirm circuit operability.
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Personnel involved with writing design changes have been informed of this event and instructed to consider the following in all future design changes:
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- 1) Avoid the use of vague words that are subject to interpretation, and 2)
Include all precautions in the design change when practical, rather than referring to another document.
1E
U. S. Nuclear Regulatory Commission
. July 19, 1989
'Page 4 Corrective Steps Which Will Be Taken To Avoid further Violations 1.
A training session associated with the squib valves will be developed covering installation and operation, and provided to CNS craft personnel.
2.
This event will be reviewed by all NPG engineering and CNS craft personnel.
3.
A permanent change will be made to Maintenance Procedure 7.2.25 to confirm circuit operability through the use of resistance verifications whenever the squib valves are replaced.
Date Of Full Compliance The corrective steps noted will be implemented and full compliance achieved by October 1989.
If you have any questions regarding this response, please contact me or G. R. Horn at the site.
Sincerely, G. A. Trevors Division Manager of Nuclear Support GAT:GRH:REW:ya cc:
U. S. Nuclear Regulatory Commission Region IV Arlington, Texas NRC Resident Inspector Cooper Nuclear Station i
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