ML20076M313
| ML20076M313 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 10/03/1994 |
| From: | Boulette E BOSTON EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BECO-LTR-94-120, NUDOCS 9411070202 | |
| Download: ML20076M313 (2) | |
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l GL 89-19 s
Boston Edison l
Pilgrim Nuclear Power Station I
Rocky Hill ficad Piyrnouth. Massachusetts 02360 I
i E. T. Boulette, PhD senior Vice President-Nuclear October 3,1994 BECo Ltr. #94-120 l
U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Docket No. 50-293 License No. DPR-35 Pilgrim Nuclear Power Station Response to Feedwater Trio Technical Specifications (TAC #M74981) 1 l
By letter dated June 20,1994, the NRC requested information from the Boston Edison Company (BECo) conceming the reactor vessel overfill (feedwater) protection trip vis-s-vis an NRC Safety Evaluation (SE) issued in response to a Boiling Water Reactor Owners Group (BWROG) initiative.
This system was installed at Pilgrim in the late 1970's and described in our letter of May 4,1990, made in response to Generic Letter (GL) 89-19.
The description provided in that letter is of a "2 out-of 2" design. The NRC SE of June 24,1994 applies to Pilgrim's Main Feedwater Pump (MFP) trip on high reactor water level, and Pilgrim was l
listed in NUREG 1218, " Regulatory Analysis for Resolution of USl A-47", Table A.1, which is one of l
the SE's criteria.
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Our "BECO-90-067, Forwards Response to Generic Ltr 89-19, Request for Action Related to Resolution of USI A-47, Safety Implication of Control Sys in LWR Nuclear Power Plants. Reactor [[system" contains a listed "[" character as part of the property label and has therefore been classified as invalid. Pump Trip Sys for Water Overfill Protection Adequate|May 4,1990, letter]] confirmed that PNPS operators are trained on the MFP trip system, associated emergency operating procedures (EOPs), and receive simulator training on the EOPs.
Our "BECO-90-067, Forwards Response to Generic Ltr 89-19, Request for Action Related to Resolution of USI A-47, Safety Implication of Control Sys in LWR Nuclear Power Plants. Reactor [[system" contains a listed "[" character as part of the property label and has therefore been classified as invalid. Pump Trip Sys for Water Overfill Protection Adequate|May 4,1990 letter]] also explained that Pilgrim's Technical Specifications No not include requirements specifically related to the MFP trip. We have reviewed your June 20,1994, request to incorporate Technical Specification changes for this trip and have concluded that such changes are not required.
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The MFP trip terminates feedwater flow when the water level in the reactor vessel ls higher than the normally anticipated operational band and lower than the steam line nozzles. The MFP trip may be encountered during the level transient following a reactor scram or upon the failure of the feedwater controller, whereby feedwater regulation valves move to their fully open positions. The feedwater controller failure event is described in Pilgrim's Updated Final Safety Analysis Report (Appendix G, Event 36). Event 36 occurs when feedwater controller failure maximum demand leads to an excess of coolant inventory. When operating, any adverse responses of the reactor caused by cooling of the moderator is compensated by a scram accomplished through the combined actions of the Neutron Monitoring Reactor Protection and Control Rod Drive Systems. When pressure relief is required it is I
achieved through the operation of the Nuclear System Pressure Relief System. As can be seen, protection from the adverse effects of cooling the moderator is provided by scrams and the pressure relief system, not directly by the MFP trip (which is not credited in the accident analysis). The purpose of the MFP trip is to prevent turbine damage due to excessive moisture carryover, and to prevent water intrusion into the steam lines, protecting the main turbine and steamlines. It can therefore be seen that this trip is a plant design feature incorporated to protect equipment, but has no nuclear 1;
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t.afety-related function.
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9411070202 941003 0'N C 50 I"
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. Technical Specifications are to impose conditions on or limit reactor operation to prevent or minirnize i
the possibility of an event that could pose an immediate threat to public health and safety. The Staff's l
Final Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors dated July 22,1993 established a specific set of objective criteria as guidance for determining which reguldtory requirements and operating restrictions should be included in the Technical Specifications.
The MFP trip is not credited for fuel protection in any design basis accident or abnormal operational i
transient described in Pilgrim's Updated Final Safety Analysis Report. Therefore, the MFP trip does not satisfy NRC inclusion criteria and should not be added to the Technical Specifications.
Furthermore, Technical Specification requirements for the MFP trip are also not necessary because Pilgrim has procedural requirements to periodically verify availability and functionality of the MFP trip, and the MFP trip is included in Pilgrim's Master Surveillance Tracking Program. Hence, the MFP trip is tasted and there would be no increase in equipment reliability resulting from adding it to Technical t
l Specifications. In addition, Pilgrim's operating procedures include steps to prevent reactor vessel overfill events and steps to mitigate reactor vessel overfill events should they occur.
For these reasons, Pilgrim will not be adding Technical Specification requirements for the MFP trip.
We also believe we have satisfied the requirements of GL 89-19 and, therefore, it should be closed for Pilgrim.
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. T. Boulette, PhD ETB/PMK/nas/TS/Feedwtr Attachment cc:
Mr. R. Eaton, Project Manager Division of Reactor Projects - 1/11 Mail Stop: 14D1 U. S. Nuclear Regulatory Commission 1 White Flint North 11555 Rockville Pike Rockville, MD 20852 U.S. Nuclear Regulatory Commission Region i 475 Allendale Road King of Prussia, PA 19406 Senior Resident inspector Pilgrim Nuclear Power Station
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