ML20040A359
| ML20040A359 | |
| Person / Time | |
|---|---|
| Site: | 05000561 |
| Issue date: | 05/17/1976 |
| From: | Israel S Office of Nuclear Reactor Regulation |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML111090060 | List:
|
| References | |
| FOIA-80-515, FOIA-80-555 NUDOCS 8201200807 | |
| Download: ML20040A359 (5) | |
Text
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NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D. C. 20666 e
E I 7 IPS Thomas A. Ippolito, Chief, Electrical, Instrumentation & Control Systems Branch, DSS Victor Benoroya, Chief, Auxiliary and Power Conversion Systems, r.,
DSS THRU:
Thom s M. Novak, Chief, Reactor Systems Branch, DSS B-SAR-205 FIRST ROUND REVIEW The enclosed coments are offered pertaining to several events analyzed in Chapter 15.0 of B-SAR-205. We are forwarding these observations to the cognizant Branches for resolution, as appropriate, It is our understanding that any further inquiry needed of the vendor with regard to the suitability of his design,in these matters will be pursued by the Branch responsible for the review of the individual systems.
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S. Israel, Section Leader Reactor Systems Branch Division of Systems Safety Office of Nuclear Reactor Regulation
Enclosure:
Coments cc:
D. Ross T. Novak S. Israel R. Fitzpatrick A. Ungaro T. Cox4c-G. Mazetis 1
1 e2012coso7 e104o3 PDR FOIA MADDEN 80-515 PDR
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ESFAS SYSTEM For a feedwater valve failure, feedwater pump failure, feedwater
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line break upstream of the first check valve, or a complete loss of feedwater, page 15.1.8-3 states that the auxiliary feedwater pumps are started on cond3tions indicative of low feedwater flow, such as LOW STEAM GENERATOR LEVEL or LOSS OF MAIN FEEDWATER PUMPS.
Since these actuation signals are not identified as ESFAS parameters in Section 7.3, it would appear that consideration should be given to upgrading the quality of this instrumentation.
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SECONDARY SIDE VALVES Credit is taken for main steam or feedwater isolation for a number of events in Chapter 15.0.
The closure times assumed for these valves should be identified and the times limited by station Technical Specifications.
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ESSENTIAL AUXILIARIES Table 15.1-5 indicates that the main feedwater isolation valves and associated controls are safety components (BOP). The interface criteria ori page 10.5-2 recognize the essentiality of main feedwater isolation by adopting seismic Category 1 valves, piping and associated supports of the main feedwater system from and including the main feedwater isolation valves.
Two qualified valves are provided (V8andV22).
However, it is noted that main steam line isolation is also a safety function for which B&W has indicated the need for safety components (B0P).
As is stated above, main feedwater isolation is properly designed with two redundant, seismic Category 1 valves in each line.
It is therefore not obvious why this same level of safety hasn't been carried to main steam line isolation (only one seismic Category 1 valve is shown in each line).
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SECONDARY SIDE MANUAL ACTIONS p.17' For the loss of offsite power event in Section 15.1.9, it is noted that operator action is required by 10 minutes for decay heat removal.
This action, as briefly described on page 15.1.9-3, is to maintain the steam relief valves (modulating atmospheric dump valves) open by continually resetting the pressure setroint. The practicality of this operation over the duration of the event is not clear. Agreement is needed that credit for manual action tc mitigate the consequences of this event is appropriate.
Suggested areas of concern are:
1.
Where are these setpoint adjustments perfonned?
2.
How many relief valves are involved?
3.
How sensitive is the 10 minute requirement to either premature actuation or delayed action?
4.
Since the operator must devote his full attention to this steam relieving manual action for at least 45 minutes (according to text), do any other conditions g_
exist to require the operator's attention during this time?
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5.
How are the setpoint adjustments physically perforced?
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