ML20092G683
| ML20092G683 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 06/15/1984 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| 2NRC-4-082, 2NRC-4-82, NUDOCS 8406250198 | |
| Download: ML20092G683 (4) | |
Text
Y 2NRC-4-082 (412) 787 - 5141 Telecopy Nuclear Construction Division June 15, 1984 Robinson Plaza, Building 2 Suite 210 Pittsburgh, PA 15205 United States Nuclear Regulatory Commission.
Washington, DC 20555 ATTENTION:
Mr. Darrell G. Eisenhut, Director Division of Licensing Office of Nuclear Reactor Regulation
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Identification of Backfit Requirement Number 5 Gentlemen:
In Draft SER Sect ion 7.3.3.15 (attached), the URC identified the concern that certain motor-operated valves, such as those for cold-leg accumulator isolation, could have circuitry which could have a nondetect-able failure.
Duquesne Light Company responded to this concern in letter 2NRC-4-032 of March 28, 1984, by proposing a circuit modification. The NRC responded to this in a letter from Mr. G. W. Knighton to Mr. E. J. Woolever dated May 8, 1984, describing even more circuit modifications which would be necessary to satisfy the staff's understanding of IEEE-279.
DLC has re-evaluated the design as described in letter 2NRC-4-076, dated June 8,1984, to the NRC and concluded that the existing design complies with IEEE-279 in that the valves are administrative 1y controlled and nonitored to insure that no " protective action" is required.
Historically, the design of the valve control for this type of valve has included provisions to administrative 1y remove the power to the valve operators in order that the valves were not inadvertently shut when
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accumulator avaiability was required.
In addition to administrative control of powe r removal, the Beaver Valley Power Station Unit 2 design includes provision to continuously monitor the valve pos it ion.
The staff position that the circuit should be designed against a nondetectable failure appears to constitute a new interpretation of IEEE-279.
10CFR 50.109, GNLR 84-08, and NRC Manual Chapter 0514 identify such a requirement as a backfit.
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United Stctes Nuclect Ragulstory Commission Mr. D rrell.G, Eisenhut, Director Page 2 DLC requests that the propo sed requirement be submit ted to NRC management fo r ap proval, in accordance with the Of fice of Nuclear Reactor Regulation (NRR) procedure for management of plant specific backfitting, prior to transmittal as a licensing requirement.
DUQUESNE LIGHT COMPANY By E. M/. Wo'olever KAT/wjs Vice President Attachment cc:
Mr. H. R. Denton (w/a)
Mr. G. W. Knighton, Chief (w/a)
Ms. M. Ley, Project Manager (w/a)
Mr. M. Licitra, Project Manager (w/a)
Mr. G. Walton, NRC Resident Inspector (w/a)
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D rc+sa mentrcl could Isad to consequential damage of safety-related e or prevent rotection systeris.
The s a
ndependence
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between manual and automatic safe
-4 astin s and believes that a safety-significant islu e introduced if the operator is prove 'tud
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- 4ap1lianed centrol, TMs 4 s-an-open-ites.
7.3.3.15 Power Lockout for Motor-Operated Valves Certain motor-operated valves, such as those for cold-leg accumulator isolation, require power 19ckout (removal) to meet the single-failure criterion.
The power lockout scheme used by the applicant uses an additional, manually controlled (via removable banana plugs) contactor.
The staff has concluded that a short or relay failure in this circuitry could constitute a nondetectable failure and thus violate the single-failure criterion.
The staff has expressed this con-corn to the applicant and considers this item open subject to its review of the applicant's pending response.
'O 4 Conclusion Later.
l 7.4 Systems Requ for Safe Shutdown l
7.4.1 Oucription andassoctNedcontrolsandinstrumentation This sectisn describes the equipmen of systems required for safe shutdown \\
also describes controls and instru-l
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mentation outside the main control m that nable safe shutdown of the plant in case the main control room a at be evacuated.
l 7.4.1.1 Safe Shutdown ystems Securing and ma ining the plant in a safe shutdown condition ca be cone i
by appro tdealignmentofselectedsystemsthatnormallyserveavar of t
ocer onal functions.
The functions that the systems recuirec for safe sn wn must provide are i
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s (1) prevent the reactor from achievfng criticality g
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"(2) provide an adequate heat sink's'o that the design and safety limits of the reactor coolant system temperature and pressure are not exceeded To perform the above functions, the systems required for safe shutdown must provide the following:
V (1) baration I
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l (2) adequate supply of auxiliary feedwater (3) residual heat removal j
In addition to the operation of systems required to provide these functions to achieve and maintain safe shutdown, the following conditions are applicable:
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(1) The turbine is tripped (in addition to automatic trip this can be accom-plished manually at the turbine as well as from the control room).
(2) The reactor is tripped (in addition to automatic trip this can also be accomplished manuelly at the reactor trip switchgear as well as from the control room).
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(3) All automatic protection and control systems are functioning (see Sec-tions 7.2 and 7.3).
1 The monitoring indicators for maintaining hot standby are as follows:
(1) water level for each steam generator (2) pressure for each steam generator 1
(3) pressuri:er water level i
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(4) pressurtzer pressure 32/21/84 7-34 BEAVER VALL!v 05!9 !!! '
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