ML17331B299
| ML17331B299 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 03/09/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17331B298 | List: |
| References | |
| GL-90-06, GL-90-6, NUDOCS 9403160298 | |
| Download: ML17331B299 (6) | |
Text
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/g UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0.176 TO FACILITY OPERATING LICENSE NO.
DPR-58 AND AMENDMENT NO.
161 TO FACILITY OPERATING LICENSE NO.
DPR-74 INDIANA MICHIGAN POWER COMPANY DONALD C.
COOK NUCLEAR PLANT UNIT NOS.
1 AND 2 DOCKET NOS.
50-315 AND 50-316
1.0 INTRODUCTION
On June 25,
- 1990, the staff issued Generic Letter (GL) 90-06, "Resolution of Generic Issue 70,
'Power-Operated Relief Valve and Block Valve Reliability,'nd Generic Issue 94, 'Additional Low-Temperature Overpressure Protection for Light-Water Reactors,'ursuant to 10 CFR 50.54(f)."
The generic letter represented the technical resolution of the above mentioned generic issues.
Generic Issue 70, "Power-Operated Relief Valve and Block Valve Reliability,"
involves the evaluation of the reliability of power-operated relief valves (PORVs) and block valves and their safety significance in PWR plants.
The generic letter discussed how PORVs are increasingly being relied on to perform safety-related functions and the corresponding need to improve the reliability of both PORVs and their associated block valves.
Proposed staff positions and improvements to the plant's technical specifications (TS) were recommended to be implemented at all affected facilities.
This issue is applicable to all Westinghouse, Babcock 5 Wilcox, and Combustion Engineering designed facilities with PORVs.
Generic Issue 90, "Additional Low-Temperature Overpressure Protection for Light-Water Reactors,"
addresses concerns with the implementation of the requirements set forth in the resolution of Unresolved Safety Issue (USI) A-26, "Reactor Vessel Pressure Transient Protection (Overpressure Protection)."
The generic letter discussed the continuing occurrence of overpressure events and the need to further restrict the allowed outage time for a low-temperature overpressure protection channel in operating modes 4, 5, and 6.
This issue is only applicable to Westinghouse and Combustion Engineering facilities.
By letters dated December 21,
- 1990, and January 6,
1993, the Indiana Michigan Power Company (the licensee) responded to GL 90-06.
By letter dated April 16, 1991, the licensee requested amendments to the TS appended to Facility Operating License Nos.
DPR-58 and DPR-74 for the Donald C.
Cook Nuclear Plant, Unit Nos, 1
and 2.
The proposed amendments are in response to GL 90-06.
This safety evaluation addresses the licensee's response to GL 90-06 as well as the proposed TS changes.
9403lb0298 PDR 'DOCK P
940309 05000315'DR
2.0 EVALUATION FOR GENERIC ISSUE 70 The actions proposed by the NRC staff to improve the reliability of PORVs and block valves represent an increase in overall protection of the public health and safety and a determination has been made that the attendant costs are justified in view of this increased protection.
The technical findings and the regulatory analysis related to Generic Issue 70 are discussed in NUREG-
- 1316, "Technical Findings and Regulatory Analysis Related to Generic Issue 70, "Evaluation of Power-Operated Relief Valve Reliability in PWR Nuclear Power Plants."
In addressing the reliability of PORVs and block valves, GL 90-06 provided three actions.
Action 1. stated:
"Include PORVs and block valves within the scope of an operational quality assurance program that is in compliance with 10 CFR Part 50, Appendix B.
This program should include the following elements:
"a.
The addition of PORVs and block valves to the plant operational guality Assurance List.
"b. Implementation of a maintenance/refurbishment program for PORVs and block valves that is based on the manufacturer's recommendations or guidelines and is implemented by trained plant maintenance personnel.
"c.
When replacement parts and spares, as well as complete components, are required for existing non-safety-grade PORVs and block valves (and associated control systems), it is the intent of this generic letter that these items may be procured in accordance with the original construction codes and standards."
The licensee stated in response that the PORVs and block valves are classified as gA-N in the plant Facility Data Base as part of the reactor coolant system pressure boundary.
In addition, maintenance of the PORVs and block val.ves was performed in accordance with manufacturer's recommendations and by trained plant personnel.
Finally, pressure-retaining components of the PORVs and block valves have been and will be procured in accordance with original construction codes and standards, and other components will, in the future, be procured in accordance with original construction codes and standards.
Based on this response, the staff considers actions in response to Action 1 to be satisfactory.
Action 2. stated:
"Include PORVs, valves in PORV control air systems, and block valves within the scope of a program covered by Subsection IWV, 'nservice Testing of Valves in Nuclear Power Plants,'f Section XI of the ASME Boiler and Pressure Vessel Code.
Stroke testing of PORVs should only be performed during Mode 3
(HOT STANDBY) or Mode 4
(HOT SHUTDOWN) and in all cases prior to establishing conditions'here the PORVs are used for low-temperature overpressure protection.
Stroke testing of the PORVs should not be performed during power operation.
Additionally, the PORV block valves should be included in the licensees'xpanded MOV test program discussed in NRC Generic Letter 89-10,
'Safety-Related Motor Operated Valve Testing and Surveillance,'ated June 28, 1989."
The licensee stated in response that the PORVs and block valves are currently in the Cook Nuclear Plant IST [Inservice Testing] program.
In addition, the PORV block valves have been included in the motor-operated valve (MOV) testing program.
Although the plant configuration does not permit separate testing of the PORV control air system, the current testing of the PORVs provides indirect assurance of proper operation of the control air system.
Modifications were also completed to allow testing on the two PORVs that have backup air supplies.
Based on this response, the staff considers actions in response to Action 2 to be satisfactory.
Action 3. stated:
"For operating PWR plants, modify the limiting conditions of operation of PORVs and block valves in the technical specifications for Modes 1, 2, and 3 to incorporate the position adopted by the staff in recent licensing actions.
Attachments...are provided for guidance.
The staff recognizes that some recently licensed PWR plants already have technical specifications in accordance with the staff position.
Such plants are already in compliance with this position and need merely state that in their response.
These recent technical specifications require that plants that run with the block valves closed (e.g.,
due to leaking PORVs) maintain electrical power to the block valves so they can be readily opened from the control room upon demand.
Additionally, plant operation in Nodes 1,
2, and 3 with PORVs and block valves inoperable for reasons other than seat leakage is not permitted for periods of more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />."
In response to action item 3, the licensee proposed changes to the Cook TS by letter dated April 16, 1991.
The proposed changes agreed with those proposed by the staff with one exception.
Because the Cook plant has three PORVs vice the typical two, the licensee proposed the allowance of one PORV or block valve inoperable indefinitely.
The licensee provided the rationale for the addition of the third PORV as an enhancement to the original design to support a full load rejection.
Subsequent modifications removed the full load rejection capability making the third PORV unnecessary for that task.
Accident analyses and the facility's Emergency Operating Procedures require only one functional PORV.
The current TS require only two of the three PORVs to be operable allowing for one to fail.
Based on the "spare" nature of the third PORV, the licensee proposed the exception to the staff guidance to allow operation in Modes 1, 2, and 3 with one PORV or block valve inoperable.
The staff considers the proposed exception to be acceptable.
In regard to the other changes, the licensee adopted the staff position on plant operations with the block valves closed due to leaking
- PORVs, by stipulating that power be maintained to the block valve during such conditions so that they can be readily opened from the control room upon demand.
Appropriate changes were also proposed to the Action statements for other PORV and block valve inoperability to be consistent with the staff guidance.
Since the remaining proposed changes are consistent with the staff's position previously stated in
the generic letter and found to be justified in the above mentioned regulatory
- analysis, the staff finds the proposed modifications to be acceptable.
3.0 VA UATION FOR GENER C
ISSUE 94 The actions proposed by the NRC staff to improve the availability of the low-temperature overpressure protection (LTOP) system represents an increase in the overall protection of the public health and safety, and a determination has been made that the attendant costs are justified in view of this increased protection.
The technical findings and the regulatory analysis related to Generic Issue 94 are discussed in NUREG-1326, "Regulatory Analysis for the Resolution of Generic Issue 94, Additional Low-Temperature Overpressure Protection for Light-Water Reactors."
In addressing the availability of LTOP
- systems, GL 90-06 required revision to the overpressure protection TS.
The requirement stated:
"added assurance of LTOP availability is to be provided by revising the current Technical Specifications for Overpressure Protection to reduce the AOT (Allowed Outage Time) for a single channel from 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when the plant is operating in MODES 5 or 6, Attachment...is provided for guidance for Westinghouse and CE plants."
In response to the required action, the licensee proposed changes to the Cook TS by letter dated April 16, 1991.
The proposed changes agreed with those proposed by the staff with, one exception.
Because the Cook plant relies on PORVs and the residual heat removal (RHR) safety valve for LTOP, the applicability of the LTOP system is limited to below 152'F.
Therefore, operability of the LTOP in MODE 4 is not applicable to Cook.
Based on the
- above, the licensee proposed to limit the applicability of the revised overpressure protection systems TS to the same MODE 5 and 6 conditions as the current TS.
Based on the previously approved use of the RHR safety valve for LTOPs at Cook, the proposed exception is acceptable.
In regard to the other
- changes, the licensee adopted the staff positions, including the revised AOT for operation with an inoperable LTOP of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> instead of 7 days.
Appropriate actions to verify a vent pathway when one is required were also added.
The staff has reviewed the licensee's proposed modifications to the Cook TS.
Because the proposed changes are consistent with the staff's position previously stated in the generic letter and justified in the above mentioned regulatory analysis, the staff finds the proposed changes to be acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Michigan State official was notified of the proposed issuance of the amendments.
The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change the requirements with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements.
The staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released
- offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a
proposed finding that the amendments involve no significant hazards consideration and there has been no public comment on such finding (58 FR 12261).
Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
6.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
John B. Hickman Date:
triarch 9.
1994