ML20236C842
| ML20236C842 | |
| Person / Time | |
|---|---|
| Site: | 05000601 |
| Issue date: | 10/23/1987 |
| From: | Kenyon T Office of Nuclear Reactor Regulation |
| To: | Johnson W WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| NUDOCS 8710270364 | |
| Download: ML20236C842 (5) | |
Text
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' October 23,.'1987
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f Docket No. 50-601 Mr. W. J. Johnson Nuclear Safety Department Westinghouse Electric Corporation Water Reactor Division Box 355-Pittsburgh, Pennsylvania 15230
Dear Mr. Johnson:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION ON RESAR SP/90 As a result of our ongoing review of PDA. Module 9 of-the RESAR SP/90
-l l-application, we require addditional information in order to complete our l
review of the electrical engineering aspects of the design. Enclosed is our-l evaluation of; the electrical power systems design of the Westinghouse Advanced l
Pressurized Water Reactor RESAR SP/90 indicating certain important aspects.of the design are missing.
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Please respond to this request within 90 days of the date of this letter.- If
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you have any questions regarding this matter, call me at (301) 492-8206.
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Sincerely, l
orig 1nal signed by Thomas J. Kenyon, Project Manager Standardization and Non-Power Reactor Project Directorate Division of Reactor Projects III, IV, V and Special Projects Office of Nuclear Reactor Regulation i
Enclosure:
As stated cc: See next page l
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October 23, 1987 Docket No. 50-601 I
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Mr. W. J. Johnson Nuclear Safety Department j
Westinghouse Electric Corporation Water Reactor Division Box 355 Pittsburgh, Pennsylvania 15230 Dear Mr. Johnson-l l
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION ON RESAR SP/90 1
As a result of our ongoing review of PDA Module 9 of the RESAR SP/90 application, we require addditional information in order _ to complete our l
review of the_ electrical engineering aspects of the design. Enclosed is our evaluation of the electrical power systems design of the Westinghouse Advanced j
Pressurized Water Reactor RESAR SP/90 indicating certain important aspects of the design are missing.
Please respond to this request within 90 days of the date of this letter.
If j
you have any questions regarding this matter, call me at (301) 492-8206.
Sincerely, 4 M ': #
Thomas J. Kenyon, Project Manager Standardization and Non-Power Reactor Project Directorate Division of Reactor Projects III, IV, V and Special Projects Office of Nuclear Reactor Regulation
Enclosure:
'~
As stated cc: See next page
h Docket No. STN 50-601 F
RE!AR-SP/90
.cc:
Trevor Pratt Brookhaven National Laboratory
. Building 130-Upton, New York 11973 Mr. William Schiviey.
Westinghouse Electric Corporation ECE-410 Mail Stop 4-08 Box'355 Pittsburgh,: Pennsylvania 15230-l r
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1 ENCLOSURE 1 REVIEW OF RESAR-SP/90 WESTINGHOUSE ADVANCED PRES 5URIZED WATER REACTOR DOCKET NO. 50-601
1.0 INTRODUCTION
1 A review of the electrical power systems design of. Westinghouse Advanced Pres-surized Water Reactor RESAR SP/90 indicated certain important aspects of the design were missing.
If incorporated. these design features would improve the design considerably for future generation plants.
l
2.0 EVALUATION
An area which needs to be addressed is the basis for the absence of a fast trans-fer (simultaneous or sequential), and/or slow transfer scheme (s) and synchronizing scheme, between the unit auxiliary transformer and the startup (or standby) trans-former.
In the absence of such a scheme, with a fault on either the main or unit auxiliary transformers, the reactor coolant pumps, which provide the pre-ferred primary coolant circulation method (as opposed to natural circulation),
would be tripped potentially challenging ESF systems. With the fast transfer, the other source of power will be connected to the normal bus to supply power to the reactor coolant pumps and, thus, avoid challenging the ESF systems.
In the interest of design improvements for future generation plants, we suggest con-sideration be given to adoption of this design feature.
Another area which needs to be addressed is the absence of a secondary winding of the ESF transfomer feeding the redundant Class 1E ESF buses. There should l
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betwoinsteadofonesecondary(4.16kV).windingoftheESFtransformerwhich l
feed the redundant Class 1E buses. Two secondary windings provide a degree of independence between the redundant Class IE systems since a transient on one ESF bus would not affect the other ESF bus as much because of the impedances of the u
secondary windings. This would provide a better design for future generation plants. Provide a modified design or justification for feeding the redundant Class 1E ESF buses from one secondary winding of the ESF transfomer.
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i' We have discovered that the information is changing as the design continues to evolve as illustrated by inconsistency in the design submitted earlier with the single line submitted in the September 10, 1987, meeting. The main generator circuit breaker shown on Figure 8.3-1 of Standard Plant Design was omitted from the single line diagram presented to the staff in September 10, 1987, mee ting.
Also, the standby transformer shown on Figure ~8.3-1 is called startup transformer on the single line diagram submitted to the staff.
It appears that your philo-sophy of feeding the auxiliary power systems during startup or planned shutdown has changed completely.
In our opinion, this is a significant change and should be addressed in the Standard Plant Design.. Explain whether during plant startup or planned shutdown you still plan to feed the station auxiliary loads via the main step up transfomer through the unit auxiliary transfomer with the'gener-ator breaker open as outlined in 8.3.1.1.1 or do you plan to' feed the station auxiliary loads through the start up transformer with the deletion of generator f
breaker as shown on the single line diagram presented in the September 10, 1987, meeting.
3.0 CONCLUSION
We have reviewed the licensee's submittal and have concluded that the electrical power system design can be improved with the addition of fast transfer scheme between the unit auxiliary and startup transfonners; and by providing the second secondary winding to the ESF transformer. Additionally, the provision or dele-tion of the generator circuit breaker in your electrical power system design should be addressed.