ML20056C463
| ML20056C463 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/15/1993 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 NUDOCS 9306240184 | |
| Download: ML20056C463 (7) | |
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a PIIILADELPIIIA ELECTRIC COMI%NY v.
NUCLEAR GROUP HEADQUARTERS 955-65 CHESTERBROOK BLVD.
WAYNE, PA 19087-5691 (215) 640-6000 June 15, 1993 STATION SUPPORT DEPARTMENT Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 U.
S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
SUBJECT:
Peach Bottom Atomic Power Station, Units 2 and 3 Regulatory Guide 1.97 - Boiling Water Reactor Neutron Flux Monitoring
REFERENCE:
Letter from T. W. Shea (NRC) to G. A.
Hunger, Jr.
(PECO), dated April 13, 1993
Dear Sir:
In the referenced letter, the NRC requested Philadelphia Electric Company (PECo) to review its neutron flux monitoring instrumentation for Peach Bottom Atomic Power Station (PBAPS),
against the criteria of NEDO-31558, " Position on NRC Regulatory Guide (RG) 1.97, Revision 3, Requirement for Post-Accident Neutron Monitoring System", to determine whether it met the criteria.
The criteria in NEDO-31558 were accepted by the NRC as alternate criteria for the neutron flux monitoring instrumentation, instead of the Category 1 criteria stated in RG 1.97.
The NRC also requested, that within 60 days of receipt lof the letter, PECo provide a response to the NRC documenting the results of the review.
As requested, we_have completed our review of the neutron monitoring instrumentation at PBAPS, and have. enclosed the results-in this letter.
Restated below are the 16 criteri6 identified in NEDO-31558, Section 5, " Functional Design Criteria for Post-Accident Neutron
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U. S. Nuclear Regulatory Commission June 15, 1993 PBAPS Units 2 and 3 Page 2 RG 1.97 Response Monitoring",.followed by PECo's comparative analysis of the~
existing neutron flux monitoring instrumentation at PBAPS.
1)
Range Alternate Requirement: 1 to 100%
RG 1.97 Requiren nt: 10-6 to 100%
Existing Capability: PBAPS meets the alternata criteria with existing Average Power Range Monitor (APRM) equipment.
2)
Accuracy Alternate Requirement: 12% of rated power RG 1.97 Requirement: None Specified Existing Capability: PBAPS meets the alternate criteria with existing APRM equipment.
The APFM system accuracy is maintained by' system calibrations.
3)
Response Characteristic Alternate Requirement: 5 sec/10% change RG 1.97 Requirement: None Specified Existing Capability: PBAPS meets the alternate criteria-with existing APRM equipment.
The APRM system response time meets the alternate requirement per General Electric design specifications.
4)
Equipment Oualification Alternate Requirement: Operate in ATWS Environment j
RG J.97 Requirement: RG 1.89 and RG 1.100 Existing Capability: PBAPS meets the alternate criteria with J
existing equipment.
U.
S. Nuclear Regulatory Commission June 15,~1993' PBAPS Units 2 and 3 Page 3 RG.1.97 Response 4)
Equipment Qualification (cont'd)
Modification 2069 replaced all of the exposed undervessel Local Power Range Monitor (LPRM) cables and connections.
These new mineral insulated stainless steel sheathed coax cables'and connections were environmentally qualified to Loss of Coolant Accident (LOCA) conditions.
Some organic coax cable remains but it is enclosed'in and protected by junction boxes and conduit and was purchased to survive a LOCA environment.
Since the LOCA environment bounds the Anticipated Transient Without Scram (ATWS) environment,,the alternate criteria is met.
5)
Function Time Alternate Requirement: 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> RG 1.97 Requirement: None Specified Existing Capability: PBAPS meets the alternate criteria with existing APRM equipment.
The APRM system is' designed for function times in excess of the alternate criteria in an ATWS environment.
6)
Seismic Qualification Alternate Requirement: Seismic Qualification not Required-RG 1.97 Requirement: Seismically Qualify Cat.l. Equipment as Important to Safety per RG 1.100 and IEEE-344 Existing Capability: PBAPS meets or exceeds the alternate criteria with existing APRM equipment as seismic qualification is not required.
7)
Redundancy and Separation Alternate Requirement: Redundancy to Assure Reliability RG 1.97' Requirement: Redundant in Division Meeting RG 1.75 Existing Capability: PBAPS meets the alternate criteria with existing lu?m4 equipment.
l The system has-three redundant channels in each of two trip j
systems.
U.
S. Nuclear Regulatory Commission June 15, 1993-PBAPS Units 2 and 3 Page 4 RG 1.97 Response 8)
Power Sources Alternate Requirement: Uninterruptable and Reliable Power Sources RG 1.97 Requirement: Standby Power Source (RG 1.32)
Existing Capability: PBADS meets the alternate criteria with existing plant equipment.
The APRMs are powered from two Reactor Protection System (RPS) high inertia Motor-Generator (MG) sets.
These MG sets are powered from separate emergency buses having automatic-alternate feeds.
A manual transfer to an uninterruptable power supply is provided as an alternate feed in the event of MG set maintenance or failure.
The Neutron Monitoring System (NMS) recorders are all powered from an uninterruptable power supply (UPS) having.
two separate feeds.
The UPS consists of an inverter and a-static transfer switch.
If the UPS inverter were to fall, the static transfer switch will pick up the. alternate feed automatically.
If the static switch were to fail, a manual transfer switch can re-energize the' recorders (continuous indication of power is provided in the main control room on the APRM power meters).
The basis for the criteria is that. power should be " reliable and available during most events in order to avoid unnecessary actions".
The total loss of off-site power is the only event analyzed which would.cause.a temporary loss of NMS indication.
NMS indication will be lost until cperator action transfers RPS feed to the alternate power supply.
Power will then be restored to 3 of the 6 APRMs.
9)
Channel Availability Requirement: Available Prior to Accident RG 1.97 Requirement: Available Prior to Accident Existing Capability: PBAPS meets the criteria with existing APRM equipment.
The APRM system provides three redunant channels in each of two trip systems; of the three, two channels are required to be operable per Technical' Specifications requirements.
i
l U. S. Nuclear Regulatory Commission June 15, 1993 PBAPS Units 2 and 3 Page 5 RG 1.97 Response 10)
Quality Assurance Alternate Requirement: Limited QA Requirements Based on Generic Letter 85-06 RG 1.97 Requirement: Application at Specified Reg. Guides Existing Capability: PBAPS meets the alternate criteria with existing APRM equipment.
The majority of the equipment in the APRM system is safety quality "Q" and as such is controlled by the PBAPS Quality Assurance (QA) Plan.
Those items which are not safety related are not controlled by the QA Plan.
A review of the guidance offered in Generic Letter (GL) 85-06 indicates that existing procedures conform to the intent of the guidance that was offered. GL 85-06 is not however directly referenced in those procedures.
11)
Display and Recording Requirement: Continuous Recording RG 1.97 Requirement: Continuous Recording Existing Capability: PBAPS meets the criteria with existing APRM equipment.
Eight channels of recording capability are provided for the continuous recording of APRM, Rod Block Monitor (RBM) or Intermediate Range Monitors (IRM) signals.
12)
Equipment Identification Alternate Requirement: Identify in Accordance with CRDR RG 1.97 Requirement: Identify as Post-Accident Monitors Existing Capability: PBAPS meets the alternate criteria with existing APRM equipment.
A detailed Control Room Design Review (CRDR), in accordance with NUREG-0737, Supplement 1, has been conducted and the equipment identified.
13)
Interfaces Alternate Requirement: No Interference with RPS Trip Functions l
1 d
~a U.
S. Nuclear Regulatory Commission June 15, 1993 l
PBAPS Units 2 and 3 Page 6 RG 1.97 Response 1
13)
Interfaces (cont'd)
RG 1.97 Requirement: Isolators to be used for Alternate Functions Existing Capability: PBAPS meets the alternate criteria with existing APRM equipment.
The non "Q" portion of the APRM system is isolated from the "Q" portions in accordance with plant licensing requirements.
14) service, Test and Calibration Requirement: Establish In-Plant Procedures RG 1.97 Requirement: Establish In-plant Procedures Existing Capability: PBAPS meets the criteria with existing APRM equipment.
The APRM system is tested and calibrated under.an established set of plant procedures to maintain plant accuracy requirements.
15)
Human Factors Requirement: Incorporate HFE Principles RG 1.97 Requirement: Incorporate HFE Principles Existing Capability: PBAPS meets the criteria with existing APRM equipment.
A detailed CRDR, in accordance with NUREG-0737, Supplement 1, has been conducted.
As a result, all NMS instumentation with high and low safety significant Human Engineering Deficiencies (HEDs) have been resolved.
Additionally, Human Factors Engineering (HFE) principles are applied to NMS modifications.
16)
Direct Measurement Requirement: Direct Measurement of Neutron Flux RG 1.97 Requirement: Direct Measurement of Neutron Flux Existing Capability: PBAPS meets the criteria with existing f.PRM equipment.
1 i
U.
S.
Nuclear Regulatory Commission June 15, 1993 PBAPS Units 2 and 3 Page 7 RG 1.97 Response The APRM system uses in-core LPRM detectors to directly measure neutron flux.
The PBAPS NMS meets the post-accident design requirements defined by the alternate requirements.
If you have any questions, or require additional information, please contact me.
Sincerely, ft 1
G.
A.
Hunga, Jr., Director Licensing Section cc:
T. T. Martin, Administrator, Region I, USNRC (2 copies)
USNRC Senior Resident Inspector, PBAPS I
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