ML18057A685
| ML18057A685 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/26/1990 |
| From: | Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-GTECI-070, REF-GTECI-094, REF-GTECI-NI, TASK-070, TASK-094, TASK-70, TASK-94, TASK-OR GL-89-10, GL-90-06, GL-90-6, NUDOCS 9101040094 | |
| Download: ML18057A685 (5) | |
Text
consumers Power POWERINli MICHlliAN'S PROliRESS Palisades Nuclear Plant:
27780 Blue Star Memorial Highway, Covert, Ml 49043 December 26, 1990 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
GB Slade General Manager POWER OPERATED RELIEF VALVE AND BLOCK VALVE OPERABILITY AND ADDITIONAL LOW-TEMPERATURE OVERPRESSURE PROTECTION - RESPONSE TO GENERIC LETTER 90-06 Generic Letter 90-06, dated June 25, 1990, requests that Consumers Power Company (CPC) advise the NRC staff of our current plans relating to the Palisades power operated relief valves (PORVs) and block valves and to low-temperature overpressure protection (LTOP).
In particular, the staff requests to know whether we intend to follow the staff positions included in Section 3.1 of Enclosure A and in Section 3 of Enclosure B to GL 90-06 as applicable; or whether we will propose alternative measures, and our proposed schedule for implementation.
The Palisades Plant has recently replaced the PORVs and block valves (November, 1989) and their associated controls.
In that process, all phases of the operation of the valves were thoroughly analyzed and tested.
Additionally, Palisades has recently installed a LTOP system in which the PORV setpoint varies with operating temperature (variable LTOP or VLTOP).
Additionally, the VLTOP operation was thoroughly analyzed to assure 10 CFR 50, Appendix G criteria are met.
The results of the analyses involved in these two installations (new valves and VLTOP) are reflected in existing Palisades Technical Specifications and administrative controls.
Many of the improvements suggested in Section 3.1 of Enclosure A and Attachment B-1 of Enclosure B have already been implemented at Palisades; however, there are some specifications suggested which we, in view of our aforementioned analyses, operational experience and testing, do not consider to be necessary or appropriate for installation at Palisades.
A.
Our response to the recommendations in Section 3.1 of Enclosure A is as follows:
9101040094 901226
- PDR ADOCK 05000255
___ f' PDR A CMS ENERGY COMPANY
NRC Recommendation 3.1.1 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 Quality 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.
CPC Response The Palisades PORVs and block valves are included in the plant operational quality assurance list. The maintenance/refurbishment program is based on the manufacturer's recommendations or guidelines and is implemented by trained personnel. Spare parts and/or components are procured in accordance with the original codes and standards.
NRC Recommendation 3.1.2 Include PORVs, valves in PORV control air systems, and block valves within the scope of a program covered by Subsection IWV, "Inservice Testing of Valves in Nuclear Power Plants," of 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 where 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' expanded MOV test program discussed in NRC Generic Letter 89-10, "Safety-Related Motor Operated Valve Testing and Surveillance," dated June 28, 1989.
CPC Response The Palisades PORVs and block valves are included in a program covered by Subsection IWV of Section XI of the ASME Boiler and Pressure Vessel Code.
The Palisades PORVs and block valves are not air operated and therefore do not employ air system control valves.
We intend to stroke t~st the PORVs in cold shutdown.
Be~ause of the valve design used at Palisades, there is no need to test PORVs above atmospheric pressure.
The valves will be exercised prior to establishing conditions where the PORVs are used for LTOP.
This is not a stroke test as specified
in the ASME code, but is performed in order to purge the valve of any condensate and thereby assure proper operation of the valve.
The block valves are included in the Palisades expanded MDV test program as discussed in Generic letter 89-10.
NRC Recommendation 3.1.3 For operating PWR plants, modify the limiting conditions of operation of PORVs and block valves in the technical specifications for Modes I, 2, and 3 to incorporate the position adopted by the staff in recent licensing actions. Attachments A-1 through A-3 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 Modes 1, 2, and 3 with the 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 />.
CPC Response The Palisades safety analysis does not take credit for operable PORVs and block valves in Hot Shutdown, Hot Standby or Power Operation.
Palisades operates with the block valves closed in these modes but does, by administrative control (System Operating Procedure SOP-I), maintain power to the block valves.
Consumers Power Company will submit proposed changes to the Palisades Technical Specifications within the schedule requested by GL 90-06.
The changes will incorporate the recommended provisions of Attachment A-1 to Enclosure A with the following exceptions:
I. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> time limit to restore a PORV or block valve to operability (Sections 3.4.4.b&d) is not adequate to perform valve repair and/or the desired shutdown.
Since Palisades operates with the block valves closed and only uses the PORVs for LTOP, it is not desirable to expedite entry into conditions requiring LTOP when one PORV is inoperable. Similarly, the 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> time limit if both PORVs are inoperable (Section 3.4.4.c) is not considered sufficient for an orderly shutdown considering the fact that the required action places the plant in conditions (i.e. Mode 3 and lower) for which LTOP is required.
- 2.
The requirement to stroke test the PORVs in Mode 3 or 4 (Section.
4.4.4.1 of Attachment A-1) will be modified to require testing in cold shutdown.
Because of the valve design used at Palisades, there is no need to test the PORVs above atmospheric pressure.
- 3. The requirement to demonstrate operability of each block valve at least once per 92 days by operating the valve through one complete cycle of full travel, unless the valve is closed due to its associated PORV being inoperable, should not be implemented.
We intend to verify the operability of the valve via a stroke test at
least once each 92 days when the plant is in Cold Shutdown and depressurized.
We do not consider it prudent to stroke the block valves with the plant at power or in hot standby or hot shutdown because of the potential for an inadvertent operation of a PORV.
It is our practice to operate with the block valves closed except when the PORVs are required for LTOP.
This mode of operation is consistent with the Palisades design basis and safety analysis.
In addition, we believe that this mode of operation is consistent with GL 90-06 in that the safety functions of the PORVs as described in Enclosure A to the Generic Letter can be met regardless of whether the block valves are normally closed or open during power operation.
B.
Our response to the recommendations in Section 3 of Enclosure B is as follows:
NRC Recommendation Modify the technical specifications and commit to use the modified technical specifications for the low temperature overpressure protection system concerning the limited conditions of operation in Modes 5 and 6 as identified in Attachment B-1 of Enclosure B.
CPC Response Consumers Power Company will submit proposed changes to the Palisades Technical Specifications incorporating the recommended provisions of Attachment B-1 of Enclosure B to this Generic Letter with the following exception:
The requirement to return an inoperable PORV to operable status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or depressurize and vent the PCS is not appropriate because it may unnecessarily restrict important operating activities during plant shutdown.
In particular, it has been our practice to conduct a PCS source term reduction evolution during planned shutdowns for refueling and maintenance outages.
The source term reduction evolution has been an important factor in reducing personnel exposure at the plant.
Because this source term reduction evolution must be conducted in cold shutdown (Mode 5) with two primary coolant pumps running and the PCS pressurized to approximately 250 psia, the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> LCO could potentially force an early termination of the PCS source term reduction effort.
An appropriate allowed outage time (AOT) will be proposed in order to limit the duration of operation with a single PORV for LTOP protection while still providing adequate operational fl exi bi l ity.
~AL-z__
Gerald B Slade General Manager CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachment
CONSUMERS POWER COMPANY Palisades Plant Docket 50-255 - License DPR-20 RESPONSE TO NRC GENERIC LETTER 90-06 At the request of the Commission and pursuant to the Atomic Energy Act of 1954 and the Energy Reorganization Act of 1974, as amended, and the Commission's Rules and Regulations thereunder, Consumers Power Company submits our response to NRC Generic Letter 90-06, dated June 25, 1990, entitled, "Resolution of Generic Issue 70, 'Power-Operated Relief Valve and Block Valve Reliability,'
and Generic Issue 94, 'Additional Low-Temperature Overpressure Protection for Light-Water Reactors,' Pursuant to 10 CFR 50.54(f)."
CONSUMERS POWER COMPANY To the best of my knowledge, information and belief, the contents of this submittal are truthful and complete.
By D~P~m~sident Nuclear Operations Sworn and subscribed to before me this ~o th day of ~
1990.
BeVeflY Avery
)NOtY Public
~
, Michigan My !tOmmission expires ~
?, !11'J.-
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