ML18046B025
| ML18046B025 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 11/02/1981 |
| From: | Johnson B CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.E.1.1, TASK-TM NUDOCS 8111060472 | |
| Download: ML18046B025 (9) | |
Text
consumers Power company General Offices: 212 West Michigan Avenue, Jackson, Ml 49201 * (517) 788-0550 November 2, 1981 Director, Nuclear Reactor Regulation Att Mr Dennis M Crutchfield, Chief Operating Reactors Branch No 5 US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
UPDATE TO NUREG-0737 ITEM IIE.1.1 "AUXILIARY FEEDWATER SYSTEM EVALUATION" By letter dated May 29, 1981, Consumers Power Company provided a preliminary response to NUREG-0737 Action Item II.E.1.1, "Auxiliary Feedwater System Evaluation".
This response contained a conceptual design for an improved auxiliary feedwater (AFW) system for the Palisades Plant, and identified additional areas of conc.ern needing resolution before the design could be finalized.
These concerns centered on potential common mode failures associated with the location of the existing A.."'W pumps in a single room.
In the intervening period it has been determined that the problems associated with using the existing pump room cannot be satisfactorily resolved in a economical manner, and therefore Consumers Power Company has decided to amend its earlier proposal for resolution of this action item.
A modified conceptual design for the improved AFW system for Palisades is contained in the attachment.
This modified design incorporates a third AFW pump in a location which is physically separate from the existing pumps which are to be retained as-is.
The design also provides the capability for automatic actuation on low steam generator level, as well as the capability of automatic isolation of one steam generator on excessive pressure differential between the steam generators.
The modified design adapts the existing, in-place, spare high-pressure safety injection (HPSI) pump as the third dedicated AFW pump.
The spare HPSI pump (P-66C) is not required by Palisades Technical Specifications, although it does provide some added flexibility in terms of plant operation. It is noted, however, that most later CE plants are provided with only two HPSI pumps, and that the HPSI pumps are seldom, if ever, used during normal operation except for testing.
Thus, Consumers Power Company has decided that the spare HPSI pump can be better utilized in safe operation of the Palisades Plant through conversion to the third dedicated AFW pump.
Because the proposed AFW deisgn represents a significant departure from the existing design, Consumers Power Company would like to meet with staff as early as is convenient to describe in more detail the modification and its
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Mr Dennis M Crutchfield Palisades Plant November 2, l98l 2
ramifications.
A meeting date early November is requested in order to permit detailed design and procurement to proceed in an orderly manner.
CPCo. hopes to install this modification during the 1983 refueling outage (now scheduled for January 1983), thus little time remains to incorporate changes which the staff and/or Consumers Power Company may deem necessary.
Brian D Johnson Senior Licensing Engineer CC JGKeppler, USNRC NRC Resident Inspector-Palisades Attachment
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REPORT TO NRC ON
- AUXILIARY FEEDWATER PHASE II MODIFICATIONS FOR PALISADES NUCLEAR PLANT PREPARED FOR CONSUMERS POWER COMPANY B.Y BECHTEL POWER CORPORATION ANN ARBOR POWER DIVISION BECHTEL JOB 12447-059 OCTOBER 1981
1.0 2.0 3.0 4.0 A~liary Feedwater Modificat.s Phase II Report to NRC October 1981 AUXILIARY FEEDWATER PHASE II MODIFICATIONS PALISADES NUCLEAR PLANT TABLE OF CONTENTS INTRODUCTION 1
DESIGN BASES 1
SYSTEM DESCRIPTION 2
SYSTEM EVALUATION 3
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Auxiliary Feedwater Modifications Phase II Report to NRC October 1981 AUXILIARY FEEDWATER PHASE !I MODIFICATIONS PALISADES NUCLEAR PLANT
1.0 INTRODUCTION
The auxiliary feedwater system (AFWS) phase II modifications for the Palisades nuclear plant, adapt the existing, in-place, spare high-pressure safety injection (HPSI) pump, *P-66C, as a third dedicated AFW pump to improve the reliability of the AFWS.'
Consumers Power Company plans to implement'(during the April 1983, plant outage) the AFWS phase II modifications discussed herein and engineered, insofar as possible, conforming to the guidelines set forth in Standard Review Plan (SRP), Section 10.4.9, and associated Branch Technical Position ASB 10-1, and to the requirements of NUREG 0737..
The evaluation of these modifications provides assurance that the objectives are accomplished by minimizing potential failures resulting from human errors, common causes, and single-point vulnerabilities.
2.0 DESIGN BASES 2.1 The AFW Phase II modifications are designed to provide the capability of manual or automatic initiation of AFW flow on low water level in either steam generator and automatic or manual isolation of the depressurized steam generator by sensing low water level and exces-sive pressure differential between the steam generators.
2.2 The AFW Phase II modifications are designed to provide safety grade AFW flow indication in the control room (CR).
2.3 The electrical equipment, instrumentation, and con-trol circuits associated with the AFW Phase II modi-fications are powered from emergency buses that meet the power redundancy requirements.
2.4* The AFW Phase II modifications are designed to pro-vide testability of the *control circuits.
2.5 The AFW Phase II modifications are designed to meet the seismic and environmental qualif{cation guidelines applicable to the Palisades nuclear plant.
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Auxiliary Feedwater Modifications Phase II Report to NRC October 1981 2.6 The AFW Phase II modifications are designed to deliver AFW to the steam generators within two (2) minutes of low levei detection in either of the steam generators.
3.0 SYSTEM DESCRIPTION The AFW Phase II modifications use portions of the existing AFWS and supplement the existing AFWS with a third dedi-cated AFW pump.
The third AFW pump is the existing, in-place, spare high-pressure safety injection (HPSI) pump, P-66C, adapted for AFW service.
In conj unction wi*th the existing AFWS, the modified AFWS consists of two electric, motor-driven pumps and one steam turbine-driven pump, piping, valves, and associated instrumentation and controls.
The third AFW pump suction connects to the existing common*
suction header of the existing AFW pumps.
The discharge line of the third AFW pump splits to feed each steam generator upstream of the existing AFW containment penetrations through which the existing AFW discharge headers feed the steam. generators.
A new automatic flow control valve and two motor-operated automatic isolation valves in series; are provided in-each feed line from the third pump.
Two similar, motor-operated automatic isolation valves, in-series, are also added in each of the existing lines to the steam generators.
These motor-operated isolation valves are provided for feed-only-good-generator (FOGG) control.
The attached sketch schematically depicts the AFWS modifications.
The third AFW pump also takes suction from the existing 125 I 000-gallon conden'sate, storage tank.
An additional crosstie from the fire protection system provides a backup water supply.
Minimum flow recirculation for the third AFW pump is pro-vided through an independent continuously operating break-doWn orifice designed to pass minimum pump design flow of*
30 gpm at maximum pressure.
Either of the motor,;_driven pumps (existing or the new one) can be used during normal startup, and shutdown modes of operation.
In automatic mode~ the motor-driven pumps start in sequence, with the existing AFW pump starting first.
They are backed up by the turbine driven pump.
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Auxiliary Feedwater Modifications Phase II Report to NRC October 1981 Each AFW pump is protected by an automatic low-suction pressure trip and the operating pump can be stopped manually from the CR.
If the AFWS initiates automatically and ~he CR has to be evacuated, the AFW flow can be controlled manually from a remote shutdown panel.
4.0 SYSTEM EVALUATION The AFWS Phase II modifications are Seismic Category I and are designed, insofar as possible, in accordance with the criteria outlined in Regulatory Guide 1.29, SRP Section 10.4.9, ASB 10-1, and NUREG-0737.
Instrumentation, controls, and electrical equipment associated with these modifications conform to the criteria set forth in IEEE Std 279-1971.
The third AFW pump P-66C is qualified as a safety-related pump and is located in the west engineered safeguard room in the auxiliary building.
Analysis indicates that the third AFW pump meets the flow requirements specified by CE as 300 gpm total, ( 150 gpm to each steam generator) and 325 gpm to one steam generator with a delay time not greater than 120 seconds from the detection of low level in either of the steam generators.
Automatic initiation logic of the existing AFWS is modified to include automatic start of the third AFW pump.
AFW flow to each stea~* generator is monitor~d in the CR in accordance with the requirements of NUREG-0737.
The interfaces and supports of new Class iE electrical, instru-mentation, and control equipment meet Seismic* category I criteria and comply with the requirements of IEEE Std 344-1975 and Regulatory Guide 1.100.
New Class lE equip-ment comply with the-environmental qualification criteria of IEEE Std 323-1974 and.Regulatory Guide 1.89.
The electrical equipment and instrument channels are powered from emergency buses which meet the power redundancy require-ments set forth in Auxiliary Systems Branch Technical Position ASB. 10-1 of the SRP, Section 10. 4. 9.
The elec-trical "distribution and equipment arrangement satisfy the single failure criteria.
Qualification of existing equipment is being evaluated under separate ongoing pro-grams.
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Auxiliary Feedwater Modifications Phase II Report to NRC October 1981 It is concluded that the AFWS Phase II modifications dis-cussed in this draft report comply with the applicable design criteria and the NRC guidelines within the con-.
straints of the plant.
These modifications provide assurance that higher reliability of the AFWS will be achieved during loss-of-main-feedwater transient condi-tions.
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Report to NRC FOR F06{:i ~M IV\\
October 1981
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