ML18153B605
| ML18153B605 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna, 05000000 |
| Issue date: | 02/03/1989 |
| From: | Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 88-737A, GL-88-17, NUDOCS 8902100319 | |
| Download: ML18153B605 (15) | |
Text
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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 W. R. CARTWRIGHT VICE PRESIDENT NUCLEAR February 3, 1989 U.S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, D.C.
20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 NORTH ANNA POWER STATION UNITS 1 AND 2 RESPONSE TO GENERIC LETTER 88-17 LOSS OF DECAY HEAT REMOVAL Serial No.
88-737A NO/SEC-UC: jmj Docket Nos.
50-280 50-281 50-338 50-339 License Nos.
DPR-32 DPR-37 NPF-4 NPF-7 Virginia Electric and Power Company has received and reviewed Generic Letter 88-17, Loss of Decay Heat Removal, dated October 17, 1988 which identified eight recommended expeditious actions and six recommended programmed enhancements to reduce the incidences of loss of decay heat removal during non-power operation.
On January 6, 1989, we provided descriptions of the actions taken or planned to address the eight expeditious recommendations and stated that we would provide a description of the specific plans and schedules to implement the six programmed enhancements by February 3, 1989.
The descriptions of the six programmed enhancements and the plans and schedules for their implementation are provided in the Attachment.
If you have any questions or require additional information, please contact us.
Attachment:
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cc: U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W.
Suite 2900 Atlanta, GA 30323 Mr. W. E. Holland NRC Senior Resident Inspector Surry Power Station Mr. J. L. Caldwell NRC Senior Resident Inspector North Anna Power Station
COMMONWEALTH OF VIRGINIA)
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COUNTY OF HENRICO
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The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by W. R. Cartwright who is Vice President -
Nuclear, of Virginia Electric and Power Company.
He is duly authorized to execute and file the foregoing document in beha 1 f of that Company, and the statements in the document are true to the best of his knowledge and belief.
Ac kn owl edged be fore me th i s _,3___ day of
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My Commission expires:
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Notary Public (SEAL)
e ATTACHMENT NORTH ANNA POWER STATION Units 1 and 2 SURRY POWER STATION Units 1 and 2 Virginia Electric and Power Company
e RESPONSE TO GENERIC LETTER 88-17 PROGRAMMED ENHANCEMENTS Generic Letter 88-17 PrograDIDed Enhancements (1) PrograD1Ded enhancements consisting of hardware installation and/or modification, and prograDIDed enhancements that depend upon hardware installation and/or modification, should be implemented:
(a) by the end of the first refueling outage that is initiated 18 months or later following receipt of this letter, or (b) by the end of the second refueling outage following receipt of this
- letter, whichever occurs first. If a shutdown for refueling has been initiated as of the date of receipt of this letter, that is to be counted as the first
.refueling outage.
(2) PrograD1Ded enhancements that do not depend upon hardware changes should be implemented within 18 months of receipt of this letter.
(1) Instrumentation Provide reliable indication of parameters that describe the state of the RCS and the performance of systems normally used to cool the RCS for both normal and accident conditions. At a minimum, provide the following in the CR: (Control Room)
(a) two independent RCS level indications
Response
As described in our expeditious actions response, Surry has one hardpiped reactor vessel level indication system operable on each unit.
North Anna will install a hardpiped reactor vessel level system on each unit during the scheduled 1989 refueling outages. A second independent channel will be ins ta 11 ed during each units subsequent r_efue ling outage.
A Decay Heat Removal Instrumentation Study was initiated on January 6, 1989.
The purpose of the study is to examine various methods for providing the additional channel of RCS level indication in the control room.
This study will be completed in September 1989 and will support installation during the refueling outages scheduled at both stations in 1990-91.
(b) at least two independent temperature measurements representative of the core exit whenever the RV head is located on top of the RV (We suggest that temperature indication be provided at all times.)
Response
As stated in the expeditious actions response, both stations require two independent core exit thermocouple (CETCs) temperature indications available in the Control Room prior to entering and during operation in a reduced inventory configuration.
This information is periodically monitored and recorded by the control room operators.
During operations where the CETCs are not available and the reactor head is still inplace, the water level in the RCS will be maintained higher than three feet below the vessel flange.
The Residual Heat Removal (RHR) system temperature indication will remain in operation and available in the control room when the CETCs are disconnected due to reactor vessel disassembly.
The RHR system temperature is recorded on a control board strip chart and provides an indication of the decay heat removal status.
The Decay Heat Removal Instrumentation Study is also evaluating the installed CETCs system and alternative methods available to supply reliable core exit temperature conditions to the control room when the
e reactor head is located on the vessel. The study will be complete in September 1989.
System enhancement alternatives that are recommended by the study will be evaluated by management and appropriate actions implemented during the refueling outages scheduled at both stations in 1990-91.
(1) Instrumentation (continued)
Provide reliable indication of parameters that describe the state of the RCS and the performance of systems normally used to cool the RCS for both normal and accident conditions. At a minimum, provide the following in the CR: (Control Room)
(c) the capability of continuously monitoring the DHR system performance whenever a DHR system is being used for cooling the RCS.
and (d) visible and audible indications of abnormal conditions in temperature, level, and DHR system performance.
Response
Currently the Control Room indications and alarms available to monitor the RHR system performance include:
- 1)
RHR suction and discharge temperature indication and trend recording.
- 2)
RHR system flow indication.
- 3)
RHR suction and discharge MOV position indication when energized.
- 4)
RHR pump current indication.
- 5)
RHR pump breaker status indication:
- 6)
RHR system low flow alarm.
- 7)
RHR pumps auto trip alarm.
- 8)
RHR pumps discharge hi pressure alarm.
- 9)
RHR pump cooling water low flow alarm.
- 10) Component Cooling (RHR heat sink) status (temperature, flow and pump current etc.)
In
- addition, during reduced inventory conditions, the RCS level instrumentation will provide RHR suction status. A low standpipe level
- alarm, installed with the hardpiped level instrumentation, provides the operators with immediate indications of a pending loss of OHR due to reduced RCS inventory.
The Decay Heat Removal Instrumentation Study is also evaluating the OHR performance indications. This evaluation will specify any additional
e indications, alarms or trending requirements needed for reliable RHR operation in normal or reduced inventory conditions.
A report will be provided by October 31, 1989 that describes the results of the Decay Heat Removal Instrumentation Study.
The report will provide an action plan outlining the additional instrumentation to be installed during the refueling outages scheduled at both stations in 1990-91.
e (2) Procedures Develop and implement procedures that cover reduced inventory operation and that provide an adequate basis for the entry into a reduced inventory condition. These include:
(a) procedures that cover nonnal operation of the NSSS, the containment, and supporting systems under conditions for which cooling would nonnally be provided by DHR systems.
(b) procedures that cover emergency,
- abnonnal, off-nonnal, or the equivalent operation of the NSSS, the containment, and supporting systems if an off-nonnal condition occurs while operating under conditions for which cooling would nonnally be provided by the OHR systems.
(c) administrative controls that support and supplement the procedures in item (a), (b), and all other actions identified in this communication, as appropriate.
Response
Virginia Electric and Power Company is participating in the Westinghouse Owners Group project to evaluate reduced inventory operations.
This project is continuing to provide guidance and information for reduced inventory operations during normal and abnormal conditions.
As established in our expeditious actions response, procedures are being developed and
. implemented to address reduced inventory operations and entry into such conditions.
These procedures are based on the preliminary WOG reduced inventory project guidance and previous plant operating experiences. They provide an adequate basis for entry into mid loop operations and recovery from a loss of RHR while in a mid loop condition.
The WOG project's final guidelines are scheduled to be issued in August, 1989.
These final guidelines will be reviewed along with experience gained from utilizing the reduced inventory procedures during the 1988-89 outages at both stations.
Procedural changes appropriate for further improving the effectiveness of reduced inventory operations will be impl~mented not later than the 1990-91 refueling outages.
e (3) Equipment (a) Assure that adequ1te operating, operable, and/or available equipment of high reliability is provided for cooling the RCS and for avoiding a loss of RCS cooling.
- Reliable equipment is equipment that can be reasonably expected to perform the intended function.
Response
Virginia Electric and Power Company is initiating a Design Basis Documentation and Configuration Management Program (design basis reconstitution) scheduled to begin in 1989.
The RHR system will be included in this program and additional equipment availability requirements may be identified.
A review of the Preventative Maintenance (PM) program requirements is scheduled for completion by October 1, 1989.
The program review will ensure that vendor recommended maintenance is performed on components that may impact RHR system performance.
- Also, a review and any required upgrade of maintenance and surveillance test procedures that affect the RHR system will be completed by October 1, 1989.
These testing and maintenance procedure upgrades will assure adequate operable OHR equipment.
(b) Maintain sufficient existing equipment in an operable or available status so as to mitigate loss of OHR or loss of RCS inventory should they occur. This should include*at least one high pressure injection pump and one other system. The water addition rate capable of being provided by each equipment item should be at least sufficient to keep the core covered.
Response
The operating procedures have been revised to ensure that equipment necessary to mitigate a loss of RHR function or loss of RCS inventory while on RHR cooling will be available.
As stated in the expeditious actions response, both stations have initiated or will initiate procedural requirements to have one Charging/High Head Safety Injection Pump and one Low Head Safety Injection Pump available, prior to and during reduced inventory operations. Also these procedures specify the Hot Leg injection flow path as being preferable with the Cold Leg injection flow path being an alternative.
e (c) Provide adequate equipment for personnel communications that involve activities related to the RCS or systems necessary to maintain the RCS in a stable and controlled condition.
Response
Currently, both stations have sound powered, radio, and public address (Gai-tronics) capability to provide communications throughout the plant including areas where activities related to the RCS or RHR system must be performed.
An Employee Involvement Team has been evaluating communication needs between the control room and other areas of the plant, with emphasis on communication inside containment.
This team is studying various state-of-the-art systems to facilitate communications, especially in areas of high noise or areas that require breathing devices.
The results of the evaluation will be reviewed by December 31, 1989 and subsequently implemented as appropriate prior to the 1990-91 refueling outages.
(4) Analysis Conduct analysis to supplement existing information and develop a basis for procedures, instrumentation installation and
- response, and equipment/NSSS interactions and response.
The analysis should encompass thennodynamics and physical (configuration) states to which the hardware can be subjected and should provide sufficient depth that the basis is developed.
Emphasis should be placed upon obtaining a complete understanding of NSSS behavior under nonpower operation.
Response
Virginia Electric and Power Company is participating in the WOG RHR/Mid Loop Analysis program which will cover areas including the thermodynamic and physical responses of the plant to a loss of RHR capacity.
The design basis reconstitution effort will also evaluate the WOG project results in the preparation of plant specific analysis which will provide us with the necessary information to determine equipment and operational requirements or limitations.
The WOG project results will be used to evaluate instrument response characteristics as affected by various factors such as actual level differences caused by locations of the RHR suction and the level measuring devices when considered against varying RHR flow rates.
Also analyzed will be various compensatory actions to mitigate or terminate potential events caused by a loss of RHR or the loss of RCS inventory. This information will be used in:
- 1) the evaluation of our procedures for RHR operation or recovery from a loss of RHR while in reduced inventory conditions, 2) the selection and configuration of instrumentation used to ensure reliable operation, 3) and the development of restrictions that may be required on system operations such as reduced RHR flow rates in Mid Loop operation or the keeping of equipment or components available which in the past may have been routinely removed from service.
(5) Technical Specifications Technical Specifications (TSs) that restrict or limit the safety benefits of actions identified in this letter should be identified and appropriate changes should be submitted.
Response
The Technical Specifications for North Anna and Surry Power Stations have been reviewed to identify any restrictions that could be imposed on the operation of the RHR system or other systems that could be required to supply water to, or cooling of the Reactor Coolant System.
For Surry, there were no Technical Specifications identified as having negative impacts on the reliability of the RHR system or restrictions on the operation of RHR or other systems needed for reliable reduced inventory operations.
North Anna has identified several Technical Specifications that currently impose restrictions on the operation of RHR.
We have been preparing changes to the Technical Specifications which will remove or modify these restrictions. These changes will:
- 1)
Eliminate the Automatic Closure Interlock on the RHR suction valves of Technical Specification 3.7.9.1.
This will be accomplished through plant specific evaluations as well as applying the Westinghouse Owners Group report on the removal of the Autoclosure Interlock, WCAP-11736.
- 2)
Modify the OPERABILITY surveillance requirements of Technical Specifications 3.7.9.1 and 3.7.9.2 to clarify surveillance testing requirements that demonstrate RHR operability. This modification will ensure more reliable pump operation by applying a more uniform standard of surveillance.
- 3)
Reduce RHR flow requirements in Technical Specification 3.4.1.3, to require 1000 gpm flow (versus the current 3000 gpm) during reduced inventory operations. This change will enhance RHR reliability during reduced RCS inventory operations by significantly reducing vortex formations and air ingestion into the RHR pumps.
(At least 3000 gpm will still be required in all MODES while performing dilution operations of the RCS.)
As new information becomes available from design basis reconstitution, the WOG Mid Loop Operations analysis project or other sources such as future industry experiences, we will review and modify, if necessary and appropriate, the Technical Specifications for North Anna and Surry.
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e (6) RCS perturbation Item (5) of the expeditious actions should be reexamined and operations refined as necessary to reasonably minimize the likelihood of loss of OHR.
Response
The actions defined in our response to expeditious actions item 5 have been developed based on the currently available knowledge and. operational experiences of the industry. Virginia Electric and Power Company will review final WOG recommendations and experience gained utilizing practices implemented at both stations during the 1988-89 outages.
We will apply new information and restrictions which will improve the effectiveness of operating practices or further reduce perturbations of the RCS and/or RHR system while the plant is in non power operational modes.
These changes will be implemented prior to the 1990-91 refueling outages.