ML20197G077
| ML20197G077 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 11/17/1983 |
| From: | Houston R Office of Nuclear Reactor Regulation |
| To: | Novak T Office of Nuclear Reactor Regulation |
| References | |
| CON-WNP-0681, CON-WNP-681 NUDOCS 8312050614 | |
| Download: ML20197G077 (6) | |
Text
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5^ -] 17 NOV 171983 i
f-!E!!0RA!!DUM FOR: Thomas 11. t!ovak, Assistant Director for Licensing Division of Licensing FR0ft:
R. Wayne Houston, Assistant Director for Reactor Safety Division of Systems Integration
SUBJECT:
titlP-2 SSER INPUT FOR CHAPTER 7; IllSTRUf'E!!TATI0fl AMD C0tlTROLS Plant !!ame: tiilP-2 Docket No.:
50-397
.g /pu,f 'e 7 $ !j_f Licensing Status: OL Responsible Branch:
LB J2 j
Project fianager:
R. Auluck Review Branen:
ICSB d
Review Status:
Incomplete Enclosed is Instrumentation anu Control Systens Branch (ICS8) input for Section 7 (Instrunentation and Controls) of the UflP-2 Supplemental Safe-ty Evaluation Report (SSER).
This input addresses outstanding issue #13 (Control Systems Failures) and confimatory issue 816 (Automatic Depressur-ization System - ADS, Low Pressure Core Spray-LPCS, and Low Pressure Cool-ant Injection - LPCI Setpoints).
Outstanding issue 113 is comprised of three separate, but related, sub-parts. First, the applicant aust demonstrate that the failure of any Class 1E or non-Class IE instrumentation bus will not result in an event requiring operator action concurrent with the failure of instrumentation upon which these actions should be based.
This issue is discussed in SER Section 7.5.2.3.
Second, the applicant must demonstrate tnat the failure of control systens exposed to the environnent following a high energy line break will not cause the event to be nore severe than assumed in the safety analyses. This issue is discussed in SER Sec-tion 7.7.2.1.
Third, the applicant must demonstrate that the failure of any power source, sensor, or instrunent sensing line con.aon to two or more control systems will not result in transients or accidents more severe than considered in the plant safety analyses. This issue is discussed in SEP Section 7.7.2.2.
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The applicant initially responded to these concerns in letter 002-33 574 dated June 24, 1933.
As a result of our review of tnis infornation, a
Contact:
R. Kendall, ICSS X29451
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T. r'avak nu+cr of questions (031.143 throujn 031.159) re<1 nesting additional in-formation were for'siirded to the applicant. The responses to tnese quas-tions..ere provided by letter,qc.p310a0 dated Fovenber 10, 1993.
Based r
on our r'2Vieu of these responses, ve conclude that the rajority of the staff's concerns regarcing outstanding issue 313 have been resolved.
Hou-ever, :e are still pursuing resolution of several re..iaining ite.s uitn the applicant. Therefore, it does not appear passible to resolve tnis issue prior to plant operation as required in the SEP.
The 1pplicant has concluded that their design conforns with staff require.ients regarding control systens failures.tnd that the failure of power busas or cor. trol systems as described above do not result in unacceptable safety consequen-ces. Therefore, we are revising the appropriate sections of the SER (en-closed) to require that outstanding issue l'13 he resolved nrior to start-up following the first refueling.
This is consistent with past staff practices on recently licensed reactors (e.g., Susquehanna, LaSalle, and crand Gulf) for this issue.
"e will provide the final resolution of this issue in a future suppleaent to the SER.
'Je have reviewed the setpoints useri for.\\0S, LOCS, and LPCI initiation on reactor vessel lo,i water level of concern in confirnatory issue ;.'14
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on our review of the final values for these setpoints, m conclude that they are acceptable, and therefore, that this issua is resolved.
OrlginalSigned By R.Wayna Houston
- a. 'Jayne Hnuston, Assistant Director for Daictor Safety Division of Systew Inte<; ration
Enclosure:
DISTRIBUTION:
As stated Docket File ICSB R/F cc:
R. attson R. Kendall (PF)(2)
A. Schwencer F. Rosa N. t.uluck AD/RS Rdg.
D. liof fnan T. Collins WNP-2 S/F 4
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7.5.2.3 IE BULLETIN 79-27, LOSS OF NON-CLASS 1E INSTRUMENTATION AND CONTROL SYSTEM POWER BUS DURING OPERATION As a result of an event involving the loss of a signi-ficant amount of control room information at the Oconee plant, the staff issued IE ButLetin 79-27.
By Letter dated April 27, 1981 (R. L.
Tedesco to R.
L.
Ferguson) the staff requested the applicant to review WNP-2 with respect to this' bulletin.
In response to this concern, the applicant initiated a detaited analysis of the WNP-2 power sources to deter-mine whether modifications (including changes to plant procedures) are required to allow the operator (s) to attain a safe shutdown condition fotLowing the loss of any Class 1E or non-Class 1E instrument bus.
This ana-Lysis has not been completed.
However, the staff has reviewed the methodology used for this analysis and determined that the methodology is acceptable.
The staff wilL require that the applicant resolve this concern prior to startup folLowing the first refueling.
Accordingly, we wilL condition the operating License to reflect this requirement.
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, 7.7.2^.1 QUALIFICATION OF CONTROL SYSTEMS Operating reactor Licensees were informed by IE Informa-tion Notice 79-22 " Qualification of control Systems" that the failure of certain non-safety grade or control equipment due to the adverse environment of a high ener-gy line break could impact the safety analyses and the adequacy of protective functions performed by safety grade equipment.
By letter dated April 27, 1981 (R.
L.
Tedesco to R.
L.
Ferguson) the staff requested the ap-plicant to review WNP-2 with respect to this concern.
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The applicant has initiated a detailed analysis of the WNP-2 non-safety grade (control) systems to deternine whether failure of these systems as the result of high energy line break events could complicate the event be-yond the FSAR analyses.
This analysis has not been com-pleted.
However, the staff has reviewed the methodol-ogy used for this analysis and has determined that the methodology is acceptable.
The staff wilL require that the applicant resolve this I
concern prior to startup folLowing the first refueling.
j Accordingty, we wilL condition the operating License
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to reftect this requirement.
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. 7.7.2.2 CONTROL SYSTEM FAILURES The staff raised the concern that two or more control systems receive power from a common source or signals from a common sensor or instrument sensing line, the failure of the power sources, sensors, or sensing Lines could result in event sequences not bounded by the FSAR Chapter 15 analyses.
By letter dated April 27, 1981 (R. L.
Tedesco to R. L.
Ferguson) the staff requested the applicant to review WNP-2 with respect to this con-cern.
In response to this concern, the applicant initiated a detailed analysis of the power sources, sensors, and in-strument sensing Lines common to two or more control systems to determine whether their failure could result in an event more severe than considered in the analyses, or require action or response beyond the capability of operators or safety systems.
This analysis has not been'compteted.
However, the staff has reviewed the methodology used for this analysis and determined that the methodology is acceptable.
The staff wi l L require that the applicant resolve this concern prior to startup folLowing the first refueling.
Accordingly, we wilL condition the operating License to reftect this requirement.
- 7.3.2. 2 AUTOMATIC DEPRESSURIZATION SYSTEM (ADS), LOW PRESSURE CORE SPRAY (LPCS) SYSTEM, AND LOW PRESSURE COOLANT INJECTION (LPCI) SYSTEM SETPOINTS The reactor vessel water level sensing switches used to initiate the ADS, LPCS, and LPCI on vessel low water Level (Level 1) initially had setpo'nts (-149 inches) very near the end of their range (-150 inches).
The staff expressed concern that setpoint drift and instru-ment errors could carry these setpoints beyond the range of their instruments, thus preventing automatic initi-ation of safety systems.
The final value estaotished for these setpoints by the applicant is -129 inches.
This revised value takes into account instrument drift, system accuracy, environ-mentally induced errors, and calibration errors and is included in the WNP-2 Technical Specifications.
These setpoints, are selected in accordance with standard Gen-eral Electric setpoint methodology which is designed to ensure that sufficient margin exists between the set-points and the end of their instrument's range.
Based on its review, the staff concludes that the level 1 initiation setpoints for ADS, LPCS, and LPCI are acceptable.
This resolves confirmatory issue 16.
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