ML25196A086
| ML25196A086 | |
| Person / Time | |
|---|---|
| Issue date: | 01/13/1978 |
| From: | Lawroski S Advisory Committee on Reactor Safeguards |
| To: | Hendrie J NRC/Chairman |
| References | |
| Download: ML25196A086 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, D. C. 20555 Honorable Joseph M. Hendrie Chairman January 13, 1978
- u. S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
REPORT ON SWESSAR-Pl, STONE AND WEBSTER ENGINEERING OORPORATION BALANCE-OF-PLANT DESIGN AS APPLIED '10 '!HE BABCOCK-205 Sl'ANDARD NUCLEAR STE.AM SYSI'EM During its 213th meeting, January 5-7, 1978, the Advisory Committee on Reactor Safeguards reviewed the application of the Stone and Webster En-gineering Corporation for a Preliminary Design Approval of its SWESSAR-Pl, a standardized nuclear balance-of-plant (BOP) design that would interface with a single-unit Babcock & Wilcox Corrpany Babcock-205 pressurized water nuclear steam system. The SWESSAR-Pl BOP design has previously been re-viewed by the Committee in relation to the Westinghouse RESAR-41 and RESAR-3S and the Combustion Engineering CESSAR-80 nuclear steam supply system designs. Reports on these reviews are dated February 11, August 18, and June 11, 1976, respectively. The Committee's report on the Babcock &
Wilcox Conpany Babcock-205 standard nuclear steam system design is dated August 18, 1977. During its review, the Cornnittee had the benefit of dis-cussions with representatives of the Stone and Webster Engineering Corpo-ration and the Nuclear Regulatory Commission Staff. The Committee also had the benefit of the documents listed.
The arrangement of SWESSAR-Pl provides extensive physical separation of critical safety-related equipment to protect against comnon node failures associated with fires or other operational contingencies. However, the concept has not yet been applied to a corrplete nuclear power plant design.
Consequently, further review of the physical separation arrangements should be made prior to the Final Design Approval or when SWESSAR-Pl is reviewed in connection with a nuclear power plant for which a construction permit is being sought.
A matter of major concern in the NRC Staff's review has been the safety-related interfaces between the SWESSAR-Pl BOP design and the Babcock-205 design, on on~ hand, and the custom-designed site-related structures and conponents, on the other hand. The responsibilities and requirements related to the SWESSAR-Pl/Babc:ock-205 interfaces have been partially de-fined in the Safety Analysis Reports for these two standardized destgns.
The Comnittee believes that these interface requirerents are satisfactory 3576
Honorable Joseph January 13, 1978 for a Preliminary Design Approval, but expects the NRC Staff and the utility applicant will examine them further in connection with a proposal to use these designs for a specific plant when it is reviewed for a con-struction permit. The interfaces between SWESSAR-Pl and the site-related features are defined in the SWESSAR-Pl Safety Analysis Report, but have not yet been subjected to the test of a corrplete design for a nuclear power plant.
The NRC Staff should review these interfaces in greater depth when a construction permit application is received.
The Committee recorranends that, during the design, procurement, construc-tion, and startup, timely and appropriate interdisciplinary system anal-yses be perforned to assure complete functional compatibility across each interface for the entire spectrum of anticipated operations and postulated design basis accident conditions (Generic Item IID-1 in ACRS Report, "Status of Generic Items Relating to Light-Water Reactors: Report No. 6," dated November 15, 1977).
The proposed orientation of the turbine-generator with respect to the nuclear island is suitable for a single unit installation. For multiple unit pooer plants, the location and orientation of the units should be such as to yield acceptably low probabilities of damage by low-trajectory turbine-generator missiles, or suitable missile shielding should be pro-vided (Generic Item II-1 in ACRS Report, "Status of Generic Items Relat-ing to Light-Water Reactors:
Report No. 6, 11 dated November 15, 1977).
The SWESSAR-Pl and the Babcock-205 designs, as do many others, utilize the concept of two-track continuous duty systems such as ventilation and service water which perform critical service functions.
In some cases the probability of failure of one of these systems is not low.
The fail-ure of the second system to start or continue to operate may cause pro-gressively da11aging consequences.
The Committee recommends that failures of this kind be evaluated to determine if the necessary reliability exists for these systems or whether remedial measures are required.
Although SWESSAR-Pl and Babcock-205 include provisions for incorporation of features which will provide physical protection of the plant, the util-ity applicant using this design should be required to demonstrate that ac-ceptable features will be incorporated into the plant (Generic Item IIC-2 in ACRS Report, "Status of Generic Items Relating to Light-Water Reactors:
Report No. 6," dated November 15, 1977).
The SWESSAR-Pl design includes some provisions which anticipate the main-tenance, inspection, and operational needs of the plant throughout its 3577
Honorable Joseph January 13, 1978 service life, including cleaning and decontamination of the primary cool-ant system, and eventual decomnissioning. However, when SWESSAR-Pl is used as a portion of a nuclear power plant license application, the Com-mittee believes that the NRC Staff and the utility applicant should fur-ther review methods and procedures for removing accumulated radioactive contamination whereby maintenance and inspection programs and ultimate deconmissioning can be more effectively and safely performed (Generic Items IIC-3A & Bin ACRS Report,"Status of Generic Items Relating to Light-Water Reactors: Report No. 6," dated November 15, 1977).
The Conmittee believes that the items mentioned above can be resolved prior to the issuance of a construction permit referencing s~vESSAA-Pl/
Babcock-205.
The NRC Staff has identified certain safety items that will require resolution prior to issuance of a Preliminary Design Approval. These matters should be resolved in a manner satisfactory to the NRC Staff.
With regard to the generic items cited in the Committee's report:, "Status of Generic Items Relating to Light-Water Reactors: Report No. 6," dated November 15, 1977, those items considered relevant to SWESSAR-Pl are:
II-2, 6, 9; IIA-4; IIC-1, 4, 5, 6; IID-2; IIE-1. In addition, attention
.is called to those items relevant to the Babcock-205 Standard Nuclear Steam System as cited in the Comnittee's report of August 18, 1977.
The Advisory Committee on Reactor Safeguards believes that, if due con-sideration is given to the foregoing and to the recorrmendations in the Committee's report of August 18, 1977 on Babcock-205, Preliminary Design Approval for SWESSAR-Pl to be used in conjunction with Babcock-205 can be granted.
References Stephen Lawroski Chairman
- 1.
Pressurized Water Reactor Reference Nuclear Power Plant Safety Analysis Report (SWESSAR-Pl) and Amendments 1 through 36.
- 2.
Report to the Advisory Committee on Reactor Safeguards by the U.S. Nuclear Regulatory Com~ission in the Matter of Stone and Webster Engineering Corporation Pressurized Water Reactor Reference Nuclear Power Plant Safety Analysis Report as Related to BSAR-205, Docket No. STN 50-495, dated November 1977.
- 3.
Stone and Webster Engineering Corporation letter from W.J.L.
Kennedy to J.F. Stolz, NRC, dated June 8, 1977, regarding numerical and analytical solutions for structural response to missile impact.
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