ML20039C348
| ML20039C348 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 12/23/1981 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.1, TASK-2.K.3.28, TASK-TM IEB-79-01B, IEB-79-1B, NUDOCS 8112290263 | |
| Download: ML20039C348 (8) | |
Text
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PHILADELPHIA ELECTRIC COMPANY co 23O1 M ARKET STREET o)
P.O. BOX 8699 8
1881 -1981 PHILADELPHIA. PA.19101 DEC2 8198! > @
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December 23, 1981 g
n Re: Docket Nos. 50-277 50-278 Mr. Darrell G.
Eisenhut, Director Division of Licensing U.S.
Nuclear Regulatory Commission Washington, DC 20555
SUBJECT:
Schedule Relief for Several NUREG 0737 Modifications on Peach Bottom Atomic Power Station
Dear Mr. Eisenhut:
This letter requests adjustments in the implementation schedule identified in NUREG 0737, " Clarification of TMI Action Plan Requirements", for several improvements in the design of the Peach Bottom Atomic Power Station Unit No.
3.
The adjustments involve four of the eighteen modifications due on or before January 1, 1982.
We are requesting an extension until February 19, 1982, to complete NUREG 0737 item II.F.1(5) (Containment Water Level).
and until April 30, 1982 to complete items II.B.3 (Post Accident Sampling System) and II.K.3.28 (Qualification of ADS Accumulators).
The engineering for these modifications was initiated in early 1980.
All of the outage related work was completed during the Unit 3 refueling outage earlier this year as planned, and a substantial portion of the non-outage installation work associated with the three modifications has been completed to date.
Currently, implementation of two of the improvements has been delayed due to a failure of vendors to deliver some of the necessary components in a timely manner.
Because of the equipment delivery delays, we are requesting minor adjustments in the implementation schedule.
6kl/
5 s 'I 9112290263 811223 PDR ADOCK 05000277 P
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r Mr.
D.
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Eisenhut Page 2 The remaining modification in question deals with NUREG 0737, item II.F.1, attachment 6, requirements regardina a containment hydrogen monitor.
The modification and the submittal of documentation to support compliance is due by January 1, 1982.
Our engineering evaluation of the existing Peach Bottom Containment Atmosphere Dilution (CAD) System hydrogen analyzers concludes that the aquipment is suitable for continued use.
The only design issue for which confirmation is pending involves the environmental qualification of several components associated with the hydrogen analyzer sampling system.
The reviews to date have not revealed any deficient analyzer components, and qualification testing is continuing on several components within the analyzer cabinets.
We propose that the environmental qualification of the hydrogen monitor be performed in accordance with the schedule applicable to Philadelphia Electric Company's efforts in response to IE Bulletin 79-01B.
The engineering evaluation of the hydrogen monitor, including an assessment of our compliance with the design criteria presented in NUREG 07?7, is presented in attachment A to this letter.
Should you have any questions regarding this matter, please do not hesitate to contact us.
Very truly yours,
/,
. x'~
A / 'l t
Attachment
A e
Attachmnt A Docket Nos. $0-277
$0-278
Subject:
Peach Bottaa Atanic Pomr Station, Units 2 & 3 Containnent Ilydrogen >bnitoring NURDG-0737, Itan II.F.l(6)
The existing PBAPS provisions for containment hylrogen nonitoring have been reviewed to assess their canpliance with the requiranents of NUREG-0737, Itan II.F.l(6). The existing equipnent has been found suitable for continued use based on the review described herein.
Description of Existing Equipnent bbnitoring of post-IOCA containment hydrogen concentration is provided by the CAD Systen Analyzers. Pedundant sets of analyzers are provided to monitor H2 concentration in each drywell and torus.
The equignent was provided in 1973 by Delphi Industries (now Consip, Inc.) under Bechtel requisition M-242.
The analyzer modules anployed are Delphi Model B 'Ihermal Conductivity Analyzers. Systen interface information is providcd on P&ID M-372.
These analyzers are not utilized during normal operation except for monthly surveillance testing per Technical Specification 4.7.A.6.c.
They will be placed in operation followmg an accident by the control roan operator in accordance with existing procedures. The analyzers may be started, sample line isolation valves opened, and calibration checks performed fran the control roan. Warm up time for stable analyzer operation is approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
Under expected post-IDCA conditions the notive force for gas sampling will be provided by the differential pressure betw en the primary containment and the analyzer exhaust, which is connectcd to the SGTS suction. Should insufficient differential pressure exist for this method of sampling, the sanple pumps provided with the analyzers for sunreillance testing purposes may be utilized.
Special provisions are not made to maintain sample line taTeratures above sample dew point. The indicated hydrogen concentration will be a conservative indication of the concentration within the containment by the amount of water vapor dilution lost due to condensation in the sample lines. All sample lines are continuously sloped toward con-tainnent or toward moisture separators and traps at the analyzers.
. Interface With Post-Accident Operations The primary containments at Peach Bottan are maintained inerted (44% O2 concentration) during unit operation in accordance with Technical Specification 3.7.A.S.
A (bntainment Atmospheric Dilution (CAD) Systan has been provided to facilitate p7st-II)CA cmbustible gas control. The CAD system analyzers describtd above are an integral part of this systcn. The systen is described it detail in PBAPS FSAR, Supplcment 1, Response to Question 14.6.
Maintet ance of containment gas concentrations below canhistible 1.imits is acc T.plished by the addition of nitrogen to limit O2 concentrations to less than 5%.
hhen the containncnt repressurization limit of 30 psig is reached, canbustible gas control is further facilitated by a controlled release of containment gas.
Indication of H2 concentration is utilized only to detertine if a level of hydrogen exists within containment such that the above described control of 02 con-centratial is needed. Based on Safety Guide No. 7 (now Regulatory Guide 1.7) assumptions, approximately one day will elapse before nitrogen addition is requircd.
Since the containments are inertcd, and post-accident canbustible gas control is maintained by oxygen deficiency, the PBAPS design is insensitive to the rate or extent of metal-water reaction up to the point where containment pressurization is limiting. This point is substantially beyond the present Regulatory Guide 1.7 design basis as dmonstrated by the consenative assessment of this margin provided in PBAPS FSAR Section 14.6.3.3.3.
An additional neans of assessing containment catustible gas concentrations is provided by the Ibst-Accident Sampling Systan being provided in response to NUREG-0737, Itan II.B.3.
This equignent will allow grab samples of drymll and/or torus gas to be taken under all plant conditions for analysis in the on-site radio-chanistry laboratory.
Caiparison Mith NURII;-0737 Requircments A suntuary of the canpliance of the existing PBAPS equignent with the clarifications of NURTI;-0737, Itan II.F.l(6) and the design criteria of MURIII-0737, Appendix B is provided below:
Clarification (1)
Design and qualification criteria are outlined in Appendix A.
Position:
The NRC Peach Bottan Project Manager has infomed us that the criteria are outlincd in Appendix B, not Appendix A.
An assessment against the criteri; provided in Appendix B is provided below.
- Clarification (2)
'Ihe continuous indication of hydrogen con-centration is not required during normal operation.
If an indication is not available at all times, continuous indication and recording shall be functioning within 30 mirates of the initiation of safety injection.
Position:
As described above, the PBAPS CAD systen hydrogen analyzers will be placcd in service by the control roan operators following a II)CA in accordance with established operating procedures. The required wornup time of approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> is sufficient response time considering the insensitivity of com-bustible gas control in inertcd containments to the rate or extent of h drogcn generation i
due to metal-water reaction.
Clarification (3)
The accuracy ard placanent of the hydrogen monitors shall be provided and justified to be adequate for their intended function.
Position:
As described above,. redundant analyzers are provided to nonitor hydrogen con-centration in each drywell and torus.
Samples are withdrawn through primary containment penetrations at the following eleuations:
drywell:
El. 127'-2" drywell:
El. 199'-9" torus:
El. 123'-0" torus:
El. 114'-0" Since the primary containment is not canpartmentalized, except into drywell and torus, multiple sample points within the containnent canpartments for each analyzer are not considered necessary.
An analysis of the erfectiveness of ccribustible gas mixing within the PBAPS pririary containment is included in FSAR Supplanent 1, Response to Ouestion 14.6 The accuracy of the hydrogen analyzers is approximately + 1% full scale, unadjusted for moisture or steam dilution within the containment. This accuracy is sufficient for their intended function, that is, determinating if a level of hydrogen exists within primary containment such that control of O2 concentration is requircd.
NUREG-0737 Appendix B Criteria Positions:
1.
The environmental qualification of the portions of this insumnentation which may be subjected to a harsh environment are being reviewed in accordance with NURED-0588 as part of PEXb's efforts in response to I.E. Bulletin 79-01B. Our reviews to date have not revealed any unqualified analyzer cmponents.
Qualification testing or equignent replacanent is continuing on several cmponents within the analyzer cabinets for which sufficient test data has not been found to be available.
Since NUREI;-0588 is not applicable to equipnent located in mild environments, we have worked with the Electric Pomr Research Institute (EPPJ) and the Atomic Industrial Forum (AIF) to develop a position on the qualification of such equiprent.
We have implemented this position by conparing the equipnent purchase specifications to the range of expected environments. De have concluded that all equignent located in mild envimments is environmentally qualified.
The analyzer modules were seismically tested to dmonstrate operability following a safe shutdown eartlquake as part of their original design verification.
A seismic analysis of the analyzer cabinets and supports has recently been cmpleted by the manufacturer. The results of this analysis have been reviewed and found acceptable.
The existing control roan recorders have not been seismically qualified. We have initiated a nodification for their replacanent.
In the rcriote event of a IfCA acompanied by a seismic event which might disable the recorder prior to its replacment, the operator can observe hydrogen concentration on the seisnically qualified control room indicators.
2.
The PBAPS containment hydrogen analyzer provisions are designed such that no single active failure will prevent the adequate display of containment hydrogen concentration to the control roan operator.
In order to assess proper analyzer operation, the capability to perfom a calibration check on each analyzer fran the control rom has been provided. An additional check may be provided by the laboratory analysis of containment gas samples taken from the post-accident sample stations. Redundant dry wll and torus analyzers are electrically independent, energized
o fran Class lE power sources, and physically separated in accordance with project separation criteria for safety-related circuits. All channels are providal with direct control roan indication and recording.
3.
All CAD systan analyzers are powered fran station Class lE powr sources.
4.
CAD systan analyzers are maintained in an operable condition during power operation in accordance with Technical Specification 3.7.A.6.c.
5.
Many of the listed Regulatory Guides pertaining to quality assurance were not in existance at the time the PBAPS CAD systan analyzers were procured. However, the analyzer systan was specified, procured, designed, fabricated, and installed in accordance with quality assurance programs which cceplied with the applicable portions of 10CFR50,e\\opendix B.
6.
Refer to discussion under " Clarification (2)", above.
7.
Co minment hydrogen concentration is displayed on analog stripchart recorders to provide the operators with trend and transient information.
8.
The CAD Analyzers are identified as a part of the CIO systan and are well understood by the operators to be for use under accident conditions. 'Ihis under-standing is reinforced by written emergency procedures which require their use.
9.
Signals fran the CAD Analyzers are not transnitted for any use other than control roan indication.
10.
The means of checking analyzer calibration which have been provided are described under (2), above.
11.
Periodic surveillance testing of the CAD analyzers during unit operation is perfonmd in accordance with Technical Specification 4.7.A.6.a.
- 12. I&unistrative control of the ramval of channels from senrice is maintained.
- 13. Administrative control of the access to setpoint adjustnents, calibration adjustments, and test points is maintained.
14.
There are no known conditions which might cause ananalous control roan indications of hydrogen concentration.
4 15.
The PBAPS hydrogen analyzers have been designed to facilitate the recognition, location, replacanent, repair, or adjustment of malfunctioning corponents and modules.
- 16. Thermal conductivity analysis of gases is a proven, reliable means of detemining hydrogen concentration.
- 17. Bbnitoring of containment hydrogen concentration during normal operation is not required in accottlance with clarification (2), above.
18.
Periodic surveillance testing of the CAD analyzers is performed in accordance with Technical Specification 4.7.A.6.a.
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