ML20039H244
| ML20039H244 | |
| Person / Time | |
|---|---|
| Site: | 05000561 |
| Issue date: | 06/07/1977 |
| From: | Cox T Office of Nuclear Reactor Regulation |
| To: | Happell J BABCOCK & WILCOX CO. |
| Shared Package | |
| ML111090060 | List:
|
| References | |
| FOIA-80-515, FOIA-80-555 NUDOCS 8201190763 | |
| Download: ML20039H244 (5) | |
Text
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5 (1) Since the DHR system is isolated at 280 F during the plant heatup phase of a startup and is put on the line at 305 F during plant cooldown, operator action is relied upon to prevent exceeding Appendix G limits at intermediate temperatures.
In addition, the staff requires additional infomation to ensure that the makeup control valve failure postulated is an appropriate assumption to maximize the inventory addition.
During shutdown plant operations with one DHR train isolated, (2) asallowedbycurrentTechnicalSpecifications,t.EhD5
.fai-lure of the remaining DHR motor-operated suction valve would remove,the plant overpressurization protection at low temperatures.
(3) Additional information is required to identify and verify that the worst-case overpressure event has been selected and analyzed.
The staff requires that each appli: ant referencing 8-SAR-205 commit to providing acceptable equipment design modificatiens which will satisfy at least the following requirements:
(1) A system shall be designed and installed which will prevent 2
the exceeding of the applicable technical specifications and
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Appendix G limits for the reactor pressure vessel during plant
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.. n cochiowrt-eestattup =Ihesystern-shallbe_ capable of.relievingc 5
pressure during overpressurization events at a rate sufficient p, t to satisfy Upset Condition Limits, particularly while the RCS s
is in a water solid condition.
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8201190763 810403 PDR FOIA MADDEN 80-515 PDR
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1 (2) The system shall be able to perform its function assuming any single active component failure. Analyses must be provided which demonstrate that the system will provide the required pressure relief capacity assuming the most limiting single failure. The cause for initiation of the event, i.e.,
operator error, component malfunction, etc., will not be considered as the single active failure. The analysis should assume the most limiting conditions (e.g., one RHR train operating or available for letdown, other components in nonnal operation when the system is water solid such as pressurizer heaters and charging pumps).
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-(3) The system shall operate automatically, providing a completely b'
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independent backup protective feature for-the operator.
(4) The overpressurization protection system shall be tested prior to placing the plant in a shutdown and cooled-down condition, or subsequent to, maintenance on the protection system.
(5) The system equipment shall be of high quality to assure oper-abi-Tf ty when-regtdred-end -shaWprovide-protection--against 2 - - ---.-
potential safety problems from inadvertent initiation during normal operation when it is not required. The system shall possess the redundancy required by IEEE 279 electrical standards.
(6) The protection system does not have to meet Seismic Category I requirements if it can be shown that an earthquake would not e
o3 of initiate an overpressure transient. The postulated earth-quake shall be of magnitude equivalent to the SSE.
If the earthquake can initiate an overpressure transient, then it shall be assumed that loss of offsite power is an expected consequence of the event and the protection system thould be designed-to Seismic Ca ngery I-requirements-and-not-require the availability of offsite power to perfom its function.
(7) The loss of offsite power shall be considered as an anticipated transient which coulJ occur while in a shutdown condition.
If this event can initiate an overpressure transient, overpressure protection systems must therefore be independent of offsite power in addition to perfoming its function assumnng any single active failure.
(8) Plant designs which take credit for an active component (s) to mitigate the consequences of an overpressurization event must include additional analyses considering inadvertent initiation or show that existing analyses bound such an event.
I (9) All potential overpressurization events shall be considered when establishing the worst case events. Some events may be prevented by protective interlocks or by locking out power. These events shall be reviewed on an individual basis.
If the interlock / power k
lockout is acceptable, it can be excluded from the analyses l
provided the controls to prevent the event are in the plant j
Technical Specifications.
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