ML20148K972
| ML20148K972 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Browns Ferry  |
| Issue date: | 05/15/1978 |
| From: | Lear G Office of Nuclear Reactor Regulation |
| To: | Niav Hughes TENNESSEE VALLEY AUTHORITY |
| Shared Package | |
| ML20148K980 | List: |
| References | |
| NUDOCS 7811200080 | |
| Download: ML20148K972 (5) | |
Text
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'o UNITED STATES
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7 NUCLEAR REGULATORY COMMISslON g
WASHINGTON. D. C. 20555 I I [..,.fD see,*
Docket Nos. 50-259 auc$ ['"'l.1, e c'l 50-260
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g and 50-296 MAY 1,/ jgg 70bI N N(I4 j
D Tennessee Valley Authority ATTN: f1r. N. B. Hughes ft.,
Manager of Power 830 Power Building Chattanooga, Tennessee 37401 Gentlemen:
RE: BR0llNS FERRY PLANT UNITS HOS.1, 2 AND 3 We as e reviewing your letter dated October 5,1976, which discusses your use of the recirculation pump trip (RPT) to mitigate the consequences of an Anticipated Transient Without Scram (ATWS). To continue our review we need to compare your design with certain criteria described in the Enclosure. Therefore, please provide the following infomation:
1.
Your detailed point-by-point description of how your RPT meets the criteria of Enclosure 1.
Identify all instances in which you believe you do not cordom to the criteria and either propose modifications to meet the criteria, or justify your design as an acceptable alternative.
2.
Provide complete logic diagrams and electrical schematics for the RPT.
3.
Propose any plant Technical Specification changes which should result from the RPT and provide a schedule for implementation.
If some of the above information has already been submitted, please provide a specific reference. You are requested to supply one signed original and 39 copies of your response within 60 days of the receipt of this letter.
Sincerely, ggtsstion rmIOD D Permanent
- th5 g temp rary ter George L r, Chief Operating Reactors Branch #3 Division of Operating Reactors O vest rsy criteria for RPT
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Endosure 30 h0: RWOV!?ROY AC3S. OECE T~~
781120003o
$nnessee. Valley Authority 2
cc:
H. S. Sanger, Jr., Esquire General Counsel Tennessee Valley Authority 400 Connerce Avenue E 11B 33 C Knoxville, Tennessee 37902 Mr. D. McCloud Tennessee Valley Authority' 303 Power Building Chattanooga, Tennessee 37401 Mr. William E. Garner Route 4, Box 354 Scottsboro, Alabama 34768 Mr. C. S. Walker Tennessee Valley Authority 400 Commerce Avenue W 90199 C Knoxville, Tennessee 37902 Athens Public Library South and Forrest Athens, Alabama 35611 I
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.6 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 pr: set level.
g 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 from the nonnal 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.
O (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 compenents will not be disabled as a consequence of the ATWS event being analyzed.
C.
RPT System Interaction with Control Systems and Scram Systems Any co'ntrol 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 i
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)relatingtoenvironment,whichareexpectedto occur in the lifetime of.a plant.
E.
Periodic Surveillance and Preventative Maintenance Testing and Calibration Periodic surveillance and preventative maintenance tests and calibration requirements shall be identified to provide continuing assurance that thr 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-O 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 o brmance with the requirements of 10 CFR 50 Appendix B shall bs vpplied 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.,
i display formats, layout and controls) and functional controls (e.g., methods, location and identification) shall be included L
. in the design.
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Maintainability The design shall include measures which enhance maintainability to reduce mean-time-to-repair and to assure the continued availability and reliability of the system for the life '.f 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 nucicar power plants of IEEE-279, dated 1971 and supplemented by paragraph (A) through (I) above.
O 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 l
the 50% confidence level.
Reliabilit of human errors, comon-mo(WASH 1400) y calculations simila the reactor safety study shall include consideration de failures and test and maintenance outages. Applicable failure rates from the Reactor Safety Study shall be used unless similar analyses are performed using more l
l current data base.
For loss-of-offsite-power transients, the l
unavailability limit is 5 x 10-2 at the 50% confidence level.
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