ML20063L377
| ML20063L377 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 09/07/1982 |
| From: | Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO. |
| To: | Miraglia F Office of Nuclear Reactor Regulation |
| References | |
| SBN-321, NUDOCS 8209090078 | |
| Download: ML20063L377 (4) | |
Text
PUBLIC SERVICE SEABROM SWON Engineering office.
Companyof NewHampshir e 1671 Worcester Road Framinoham. Mossochusetts 01701 (617) - 872 - 8100 September 7, 1982 SBN-321 T.F.
II 4. 4.9 8 8 7.1.2 United States Nuclear Regulatory Commission lia shing ton, D. C.
20555 At tent io n:
Mr. Frank J. Miraglia, Chief Licensing Branch No. 3 Division of Licensing Re fe re nc e s:
(a)
Construction Permit CPPR-135 and CPPR-136, Docket No s. 50-443 and 50-444 (b)
PSNil Le t ter, dated August 27, 1982, " Reliability Analysis of the F.nergency Feedwater System", J. DeVincentis to F. J. Miraglia (c)
PSNil Letter, dated July 27, 1982, " Response to Requests for A3ditional Information (RAIs) from Instrumentation and Controls Systems Branch (ICSB);
A-K",
J. DeVincentis to F. J. Miraglia
Subject:
Seabrook Station Emergency Feedwater System Design Changes
Dear Sir:
During the Staf f review of the Seabrook Station Emergency Feedwater System (ERJ), a number of design changes have been recommended and are being implemented.
These design changes are based on the review of the Emergency Feedvater System Reliability Analysis [ Reference (b)) and also bring the Seabrook design into compliance with the latest Standard Revie4 Plan.
The se design changes will be incorporated into a revision to the Final Safety Analysis Report as soon as the final details are established.
The following describes design changes which are presently being implemented relative to the Seabrook EFW System.
An attached simplified sketch is included for clarification of some of the design changes.
1.
A continuous minimum flow recirculation path will be provided f rom each EFil pump's discharge to the condensate storage tank via the opposite pump's suction line.
This recirculation path will assure a continuous flow through an ERJ pump should flow to all four steam generators be reduced below that necessary to prevent pump damage.
The original recirculation path will be retained for use during periodic pump perf ormance testing.
/deo/
B209090078 820907 PDR ADOCK 05000443 A
United States Nuclear Regulatory Commission September 7, 1982 At tent io n:
Mr. Frank J. Miraglia, Chief Page 2
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2.
Re d unda nt, safety grade flow isolation valves will be provided in each EFW branch supply line to each steam generator.
Safety grade controls will be provided at both the main control board and remote shutdown locations for these valves.
Further information relative to this modtfication can be found in Reference (c).
3.
Manual isolation valves will be provided upstream of each pair of flow isolation valves to each steam generator.
These manual isolation valves will permit isolation of any EFW flow isolation valve while retaining the availability of both EFW pumps and the Startup Feedwater pump.
4.
Safety grade, Selsmic Category 1 air accumulators will be provided as a back-up air supply for the actuators of both main steam supply valves (MS-V127 and MS-V128) to the turbine-driven EFW pump, P-37A.
These accumulators will be sized to provide at least two complete valve operations plus maintain the valves closed for a minimum of four hours.
This safety grade air supply will upgrade the reliability of these valves consistent with the Class LE controls presently utilized in the design.
5.
The Startup Feedwater (SUF) pump discharge valve to the EFW header, FW-Vl56, will be relocated out of the EFW Pump Room.
This will assure the.2bility to cross-tie the SUF pump to the EFW System should use a series of potential failures render both EFW pumps inoperable and the EFW Pump Room inaccessible.
Additionally, during both our in-house and your Staf f review of Ref erence (b), three areas were found which should be clarified or corrected.
First, on Page 12 of Reference (b), an asterisk notes that only one of the steam admission valves (MS-V127) to the turbine-driven EFW pump can be controlled f rom the remote shutdown panels.
In conjunction with modification #4 listed above, Class LE controls for the other steam admission valve (MS-V128) will also be provided at the remote shutdown loca t io n.
These modifications will ensure the ability to start and/or stop the turbine-driven EFW pump f rom either the main control board or the remote shutdown panels.
Second, on Page 15 of Reference (b), relative to the manual valve realignments required to provide SUF pump flow to the EFW header, it states that the SUF pump rectreulation isolation valve (FW-V109) must be closed to prevent a diversion of pump flow to the Condensate Storage Tank (CST) should the rectreulation flow control valve (PCV-4326) fail open.
Uhat was not considered, however, is that the capacity of the SUF pump is significantly greater than that of an EFW pump.
At a TDR equivalent to the design rating of the EFW pump, the SUF pump has a flow capacity greater than an EFW pump, even when maximum flow is diverted back to the CST through the rec treulation valve.
The re fo re, it is unnecessary to close valve FW-V109 to ensure suf ficient flow f rom the SUF pump to the steam generators.
This is one less manual action necessary for this operation.
Third, on Page 29 of Reference (b), a note on the bottom of the page indicates that a loss of of f-site power will result in closure of the
United States Nuclear Regulatory Com:ntssion September 7, 1982 At ten t io n:
Mr. Frink J. Miraglia, Chief Page 3 mitn feedw: iter isolation valves.
This note is incorrect - the main feelwater isolation valves will not close due to a loss of of f site power.
A-iditionally, it should be noted that the loss of off-site power does not re sul t in a loss of control of the a tin feedwater regulating valves nor the main feedwater regulating bypass valves.
The result is, the SUF pump can be utilized to supply feeJwater to the steam generators
<iuring a loss of of f site power event without the need of manual valve alignments to provide flow through the ERJ System.
Flow from the SUF pump to the steam generators can be accomplished uttilzing the normal m.11n Fee]witer System.
It is hoped that the above information will assist your Staf f in their evaluation of the Seabrook Station Energency Feedwater System and preparation of the Safety Evaluation Report.
If further inf ormation is necessary, ple:Ise feel f ree to contact us.
Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY q
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J. DeVincentis Project :11 nager PA/kac l
cc:
Mr. Robert Ja ro s s, Argonne National L1boratories
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