ML20235S447
| ML20235S447 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 10/02/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20235S422 | List: |
| References | |
| NUDOCS 8710080504 | |
| Download: ML20235S447 (4) | |
Text
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9 UNITED STATES
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NUCLEAR REGULATORY COMMISSION o
- E WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0.76 TO FACILITY OPERATING LICENSE NPF-9
-j AND AMENDMENT NO. 57 TO FACILITY OPERATING LICENSE NPF-17 DUKE POWER COMPANY DOCKET NOS. 50-369 AND 50-370 McGUIRE NUCLEAR STATION, UNITS 1 AND 2 I.
INTRODUCTION Following the accident at Three Mile Island (TMI) Unit 2, the Commission issued 10 CFR 50.44(C)(3)(111) and established requirements for the install-ation of reactor coolant system high point vents on each light-water nuclear power reactor. By NUREG-0737, " Clarification of TMI Action Plan Requirements,"
dated November 1980, the Commission identified items for which Technical Specifications (TSs) are required.
This included Item II.B.1, " Reactor Coolant System Vents." By Generic letter (GL) 83-37 dated November 1,1983, the Coninission discussed those NUREG-0737 items scheduled for implementation after December 31, 1981, and provided guidance in the form of model TSs for use by PWR licensees submitting associated applications for license amendments.
By letters dated September 6, 1984, and May 20, 1987, Duke Power Company (the licensee) proposed license amendments to change the TSs for McGuire Nuclear Station, Units 1 and 2, in response to GL 83-37 regarding reactor coolant system (RCS) vents. Specifically, the amendments add new TS 3/4.1.11
" Reactor Vessel Head Vent Systems" and associated Bases 3/4.4.11.
Revised TS index pages are also included.
EVALUATION The purpose of a RCS vent system is to provide improved operational capability to maintain adequate core cooling following an accident by venting nonconden-sible gases which might otherwise inhibit core cooling during natural circu-lation. Need of the vents would occur during the recovery phase of a severe accident once core cooling by natural circulation is restored so that the reactor coolant system can be cooled down and depressurized.
If a bubble of noncondensible gas were present in the reactor vessel head, the gas could be relieved through the vent lines to prevent its relocation to the steam generators where it would retard natural circulation. The high point vents are not required to mitigate any design basis accident.
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1 The McGuire RCS vent system is comprised of two subsystems: the reactor vessel head vent system and the power operated relief valves (PORVs) located at the top of the pressurizer.
Existing TSs 3/4.4.4 and 3/4.4.9.3 address operability of the PORVs, and their flowpaths provide for the function as a RCS vent path in accordance with NUREG-0737, item II.B.1 and 10 CFR 50.44(c)(3)(iii). Therefore, no additional TS or change is included in these amendments regarding venting of the pressurizer.
Similarly, as clarified by 10 CFR 50.44(c)(3)(iii), high point vents are not required for tubes in the U-tube steam generators. Accordingly, the TS changes by these amendments are limited to the reactor vessel head vent system.
The model TSs of GL 83-37 specify surveillance of the RCS vent system every 18 months by (1) verifying that manual isolation valves in the vent path are locked open, (2) cycling each remotely operated valve from the control room, and (3) verifying flow through the reactor coolant vent lines during venting at cold shutdown or refueling. The TS changes by these amendments include items (2) and (3) but omit item (1).
Item (1) is omitted because there are no manual isolation valves in the McGuire vent paths, and omission of item (1) is, therefore, acceptable.
For item (3), temperature rise is used at McGuire as the means to verify reactor vessel head vent " flow." No specific size or flow rate is required to exhaust noncondensible gases; rather, the intent of item (3) is to verify availability of the vent flowpath.
Therefore, use of temperature rise for " flow" is acceptable. These surveillance requirements meet 10 CFR 50.44, which requires a high probability that the valves will perform their safety function, and NUREG-0737 Item II.B.1 requirements for provisions to test the operability of the vent system.
The amendments also add Bases 3/4.4.11 " Reactor Vessel Head Vent System" and revised index pages to the TSs. These changes have no adverse safety implications and are, therefore, acceptable.
The Comission finds that the licensee's proposed TS changes comply with those in GL 83-37 and are, therefore, acceptable.
ENVIRONMENTAL CONSIDERATION These amendments involve changes to the installation or use of facility com-ponents located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational exposure. The NRC staff has made a determination that the amendments involve no significant hazards consideration, and there has been no public comment on such finding. Accordingly, the amendments meet the eligi-bility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
VI.
CONCLUSION The Commission made a proposed determination that the amendments involve no significant hazards consideration which was published in the Federal Register j
(50 FR 37078) on September 11, 1985. The Commission consulted with the state
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of North Carolina. No public coments were received, and the state of North Carolina did not have any comments.
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We have concluded, based on the considerations discussed above, that:
(I) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: Darl S. Hood, PDII-3/DRP]/II E. Lantz, SRXB Dated: October 2, 1987
DATED: October 2, 1987
, AMENDf1ENT N0.76 TO FACILITY OPERATING LICENSE NPF McGuire Nuclear Station, Unit 1 AMENDMENT NO.57 TO FACILITY OPERATING LICENSE NPF McGuire Nuclear Station, Unit 2 DISTRIBUTION:
Docket Filea NRC PDR Local PDR PRC System PD#II-3 Reading M. Duncan D. Hood D. Hagan T. Barnhart (8)
W. Jones ACRS(10)
OGC-Bethesda S. Varga/G. Lainas U. Cheh ARM /LFMB GPA/PA E. Butcher L. Reyes E. Lantz l
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