ML20002C598
| ML20002C598 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 05/26/1978 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Bixel D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8101100545 | |
| Download: ML20002C598 (6) | |
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- MAY 2 g 1978 Consumers Power Company ATTN: Mr. David Bixel Nuclear Licensing Administrator,'
212 West Michigan Avenue l
Jackson, Michigan 49201
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Gentlemen:
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I By letter dated August 31, 1976, we requested that.you comit to install i
a recirculation pump trip in the Big Rock Point Plant to provide additional l
protection for the public health and safety from a postulated, anticipated transient without scram ( ATVS}.
In. response, your letter _ dated October 11, 1976, stated your conytetions,that a recircu~1stio'n pump trip is not required at the Big Rock Point Plant because of the plant procedures wtiich rewire rapid manual shutdown followirig certain transients. Your letters of i
October 11, 1 974, and Moyenber 21, 1975, provided an analysis of contain-ment pressures and temperatures that could result from an ATWS assuming manual operation of the recirculation punp trip within 1 to '5 minutes of
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the event. We do not grant credi_t for operator action in less than 10 i
minutes following a transient,or emergency condition.
Your analysis shows that the design limits are exce'eded 1,f a puip trip is delayed,for 10' minutes following initiation of the transient..
In a telephone conversation ed May 17, 1978, representatives of i
staff agreed that a recircula' tion pw:,ip trip you.ld be installed a,your t the Sig Rock Point Plant to previde the additional protection and to satisfy
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our re@irements. Please use the ' crit'eria provided in the enclosure in~
l the design of the recirculation _pdep, trip. j,
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Within 60 days of the receipfof this letter please provide a confirmation i
of your intent to install a rectrY:ulation pdmp trip and your schedule for i
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installation. Also provide ti,e folloiting,information-i 1.
Your detailed point-by-point description of how your RPT meets the criteria of Enclosure 1. ildentify all instances in which you believe you do not conform, to the criteria and either propose l
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modifications to meet the, crit,eria,,or justify your design as an i
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acceptable alternative.
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Provide complete logic diagres and electrical schematics for the RPT.
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Propose any plant Technical Specification changes which should result fra the RPT and provide a schedule for impleentation.
If you have any questions, please contact Stan Nowicki on 301-492-7403.
Sincerely.
Orh:naf 0, mad by Dennis L' ZimaEn", Chief
' Operating Reactors Branch #2 '
[ Di, vision of Operating Reactors
Enclosure:
Criteria for Recirculation Pep Trip (RPT) in Operating BWR's cc w/anclosure:
See next page DISTRIBUTION Docket NRC PDR Local PDR ORB #2 Reading VStello DEisenhut 0 ELD OI&E (3)
DLZiemann SJNowicki HSmith BGrimes TBAbernathy JRBuchanan ACRS (16)
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NRC PORM 318 (9 76) NRCM 0240 A u. e, sovsmeemawr enmtme orreca. sore-essene
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I'7I 2 +7 0 78 Consumers Power Company cc w/ enclosure:
Mr. Paul A. Perry, Secretary Consumers Power Company 212 West Michigan Averue Jackson, Michigan 49201 Judd L. Dacon,' Esquire Consumers Power Company 212 West Michigan Avenue Jackson, liic higan 49201 Hunton & Williams George C. Freeman, Jr., Esquire P. O. Box 1535 P.ichmond, Virginia 23212 Peter W. Steketee, Esquire 505 Peoples Building Grand Rapids, Michigan 49503 Charlevoix Public Library 107 Clinton Street Cha rl evo i.t:, Michigan 49720 i
P00R ORIGINAL
E ENCLOSURE 1 CRITERIA FOR RECIRCULATION PUMP TRIP (RPT) IN OPERATING BWR'S A.
General Functional Requirement The RPT system shall automatically initiate the appropriate action whenever the conditions monitored by the system reach a preset level.
B.
Independence and Integrity The RPT system and components shall be independent and separate from components and/or systems that initiate the anticipated transient (s) being analyzed and diverse frs the nomal scram system (postulated to fail) to minimize the probability of the ATWS disabling the operation of the mitigating system.
Diversity can be achieved by incorporating as many of the following methods as is practicable:
(1) Use of components from different manufacturers.
(2) Use of electromechanical devices versus electronic devices.
(3) Use of energized versus deenergized trip status.
(Forsome components, such as relays, this alone may not be acceptable).
(4) Use of AC versus DC power sources.
(5) Use of sensors employing different principles for measuring the same parameters.
Tests and/or analyses shall be performed to demonstrate that the function of the RPT system and components will not be disabled as a consequence of the ATWS event being analyzed.
C.
RPT System Interaction with Co'ntrol Systems and Scram Systems Any control systems or control equipment and components that are used for both normal control functions and as part of the RPT system shall be classified as part of the RPT system and shall meet all the requirements for the RPT system, including independence from the scram system.
For shared components, test and/or analyses shall be performed to demonstrate that no credible failures exist in the portions of the control systems which interface with the shared system that could disable the RPT system.
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.. D.
Equipment Qualification The RPT system equipment and components shall be tested to verify that the system will provide, on a continuing basis, its functional capability under conditions relevant to the postulated ATWS, including extremes of conditions (as applicable) relating to environment, which are expected to occur in the lifetime of a plant.
E.
Periodic Surveillance and Preventative Maintenance Testino and Calibration Periodic surveillance and preventative maintenance tests and calibration requirements shall be identified to provide continuing assurance that the RPT system, including sensors and actuated equipment, is capable of functioning as designed and that system accuracy and performance have not deteriorated with time and usage. These requirements shall be particularly
. directed toward the detection of those failures or degradation of accuracy and performance which would not otherwise be likely to be detected during the course of normal operations.
Integrated system testing shall also be performed to verify overall system performance. The frequency of testing and calibration shall be determined and justified in accordance with the availability and reliability requirements of the system.
F.
Quality Assurance A quality assurance program in conformance with the requirements of 10 CFR 50 Appendix B shall be applied to the RPT system design and equipment.
G.
Administrative Controls Administrative controls shall be established to control the access to all set point adjustments, calibration and test points.
H.
Information Readout The RPT system shall be designed to provide the operator with accurate, complete and timely information regarding its status.
For those functions, including operations, test or maintenance, and calibration, which require direct operator interaction, human engineering factors such as information displays (e.g.,
display formats, layout and controls) and functional controls (e.g., methods, location and identification) shall be included in the design.
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Maintainability The design shall include measures which enhance maintainability to reduce mean-time +.o-repair and to assure the continued availability and reliability of the system for the life of the plant. The system design shall include features which facilitate the recognition, location, replacement, repair and/or adjustment of malfunctioning equipment, and components or modules.
J.
Availability and Reliability Two options are provided.
Fulfilling the requirements of either (1) or (2) below will provide the reliability appropriate for the RPT system.
Option 1 The RPT system shall satisfy all requirements for a safety system in the nuclear power plants of IEEE-279, dated 1971 and supplemented by paragraph (A) through (I) above.
t Option 2 The RPT system shall satisfy (A) through (I) above and in addition for all initiating events except loss of offsite power shall have a calculated unavailability of approximately 10-3 per demand at i
the 50% confidence level. Reliability calculations similar to the reactor safety study (WASH 1400) shall include consideration of human errors, common-mode failures and test and maintenance outages. Applicable failure rates from the Reactor Safety Study shall be used unless similar analyses are performed using more current data base.
For loss-of-offsite-power transients, the unavailability limit is 5 x 10-2 at the 50% confidence level.
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