ML25196A269
| ML25196A269 | |
| Person / Time | |
|---|---|
| Issue date: | 08/18/1977 |
| From: | Bender M Advisory Committee on Reactor Safeguards |
| To: | Hendrie J NRC/Chairman |
| References | |
| Download: ML25196A269 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, D. C. 20555 Honorable Joseph M. Hendrie Chairman August 18, 1977 U. S. Nuclear Regulatory Comnission Washington, DC 20555
Subject:
REPORI' ON BABCOQ{-205 STANDARD NUCLEAR STEAM SYSTEM
Dear Dr. Hendrie:
At its 208th Meeting, August 11-13, 1977, the Advisory Committee on Reactor Safeguards completed its review of the application of Babcock
& Wilcox Company (Applicant) for a Preliminary Design Approval (PDA) for its Standard Nuclear Steam System (NSS), Babcock-205. A Sulx::omnittee meeting was held with representatives of Babcock & Wilcox Company (B&W) and the Nuclear Regulatory Commission (NRC) Staff in Washington, D.C.,
on July 27, 1977. The Committee had the benefit of discussions with representatives of the NRC Staff and the Applicant. The Cornnittee also had the benefit of earlier reviews of other Standardized Nuclear Steam Supply Systems and of the documents listed.
The B&W Standard Safety Analysis Report (B-SAR-205) describes the B&W standardized two loop NSS for a 3820 MWt pressurized water nuclear plant with a core thermal power output of 3800 MWt.
Its scope in-cludes the Reactor, Reactor Coolant System, Pressurizer Relief System, Emergency Core Cooling System, Decay Heat Removal System, Chemical Addition and Boron Recovery System, Makeup and Purification System, Instrumentation and Controls, and Fuel Handling System.
The reference design is similar to recent B&W 3620 MWt NSS designs reported on by the Cornmittee: Bellefonte Nuclear Plant Units 1 and 2 (July 16, 1974),
Washington Public Power Supply System Nuclear Power Stations 1 and 4 (June 11, 1975) and Pebble Springs Nuclear Plants 1 and 2 (February 11, 1976). Earlier ACRS reports on PDA applications for standard reference nuclear steam supply designs are the March 14, 1975 report on the General Electric Company GESSAR-238 Nuclear Island and the Dece~ber 17, 1976 report on the General Electric Company GESSAR-238 and GESSAR-251 Nuclear Steam Supply Systems, the September 17, 1975 report on Combustion Engineer-ing, Inc., CESSAR-80, and the Sept2ffiber 18, 1975 and July 14, 1976 reports on Westinghouse Electric Corporation RESAR-41 and RESAR-35.
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Honorable Joseph August 18, 1977 The Applicant has selected horizontal ground accelerations of 0.3g and 0.15g as appropriate design values for the safe shutdown and opera-ting basis earthquakes, respectively. Designs for the protection of Babcock-205 safety-related components and systems from other site-related hazards will be included in the balance of plant design. The reference NSS design includes the*interface requirements information essential to a balance of plant safety design consistent with the assurrptions used in the NSS design-basis accident analyses. Since the utility-applicant will be responsible for instituting the quality assurance programs necessary to assure that all safety-related design requirements have been met, the Corrmittee will review these matters in more detail with the utility-applicants on a case-by-case basis.
The N.RC Staff had listed thirteen outstanding issues in its report to the ACRS.
The N.RC Staff now believes that it has the information it needs to resolve eight of the thirteen issues, and that the remaining five issues can be resolved before the anticipated ti.111e of granting the PDA.
The ACRS recommends that all outstanding issues be resolved in a manner satisfac-tory to the NRC Staff.
The Committee believes that for Babcock-205, as well as for other standardized nuclear stea~ supply systems, studies should be made to quantify the reliability, effectiveness and safety margins for the Emergency Core Cooling Systems. The studies should include evaluation of current N.RC and EPRI programs on alternate ECC Systems to determine what, if any, improvernents are practicable and desirable. These efforts will require the substantiation of the bases for best estimate analyses and verification of codes, and increased input to and participation in the related N.RC progra'11S for safety research.
New features in the instrument and control systems have been introduced through the specification of functional designs and design criteria which the N.RC Staff has found to be adequate for the PDA.
On all issues involving instrwnentation and control, the Corrmittee will use the case-by-case basis to ascertain progress of the work until the Babcock-205 design has progressed to the stage where Final Design Approval is achieved.
The Corrunittee has encouraged Applicants to consider instrumentation with the necessary ranges and diversity to follow the course of an accident.
Regulatory Guide 1.97 (Revision 1) embodies these recorrmendations.
For standardized PWR's, such as Babcock-205, the Corrrnittee recommends that a study be made of the merits of including instrumentation to sense the water level in the reactor pressure vessel.
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Honorable Joseph M. Hendrie 3 -
August 18, 1977 The Babcock-205 design includes provisions which anticipate maintenance, inspection, and operational needs of the plant throughout its service life. The Committee believes that the NRC Staff and the Applicant should continue to seek improvements in provisions of this type and, in addition should review procedures for reroving accumulations of radioactive contamination so that maintenance and inspection programs and eventual decommissioning can be more effectively and safely carried out.
The Comni ttee believes that B&W and the NRC Staff should intensify their review for design provisions that will further improve protection against sabotage and that provisions found timely should be incorporated in early applications of Babcock-205.
With regard to other generic problems cited in the Corrnnittee's report, "Status of Generic Items Relating to Light-Water Reactors: Report No. 5," dated February 24, 1977, items considered relevant to Babcock-205 are: II-3, 4, 5, 6, 7, 9, 10; IIA-3, 4, 5, 6, 7; IIB-1, 2; IIC-1, 4, 5; IID-1, 2. These problems should be dealt with by the Staff and the Applicant as solutions are found.
The Corrmittee believes that methods that seek to develop reference systems through standardization and through replication need to be coupled with ongoing programs that will permit design changes which improve safety and which, when justified, will be implemented in a timely manner.
Use of reference systems should lead to more efficient and ef-fective licensing reviews. Standardized designs such as Babcock-205 will contribute to this process. A transition period will be required in which the Committee will still give attention to the items noted, on a case-by-case basis.
The Corrrnittee believes that, subject to the above cornments and success-ful completion of the R&D programs, the Babcock-205 design can be suc-cessfully engineered to serve as a reference system.
1923 Sincerely yours,
{};1, ~~
M. Bender Chairman
Honorable Joseph August 18, 1977
REFERENCES:
- 1. The B&W Standard Safety Analysis Report (S-SAR-205) and Amendments 1 through 16.
- 2. Report to the Advisory Corrnnittee on Reactor Safeguards by the Office of Nuclear Reactor Regulation, (ONRR), U. S. Nuclear Regulatory Conmission in the Matter of Babcock and Wilcox Company Reference Safety Analysis Report, B-SAR-205, Docket No. STN 50-561, July 8, 1977.
- 3.
Babcock and Wilcox letter to ONRR, Attention: Mr. Roger S. Boyd,
Subject:
B-SAR-205 - Outstanding Issues, dated July 15, 1977, Docket STN 50-561.
- 4.
Babcock and Wilcox letter to ONRR, Attention: Mr. Roger S. Boyd,
Subject:
B-SAR-205 - Outstanding Issues, dated July 21, 1977, Docket STN 50-561.
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