ML20203H820
| ML20203H820 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 02/12/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20203H808 | List: |
| References | |
| NUDOCS 9902230127 | |
| Download: ML20203H820 (2) | |
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UNITED STATES g
j NUCLEAR REGULATORY COMMISSION o
2-WASHINGTON, D.C. 2066& 4001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.166TO FACILITY OPERATING LICENSE NO. DPR-28 VERMONT YANKEE NUCLEAR POWER CORPORATION VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-271
1.0 INTRODUCTION
The Vermont Yankee Nuclear Power Station is a boiling water reactor (BWR), model BWR-4, with a Mark I containment. By "BVY-98-119, LAR 206 to License DPR-58,correcting Error in TS 4.9.2 Re Calibr of Augmented Offgas Sys [[Atomic Element" contains a listed "[" character as part of the property label and has therefore been classified as invalid. Monitors|letter dated December 10,1998]], the Vermont Yankee Nuclear Power Corporation, the licensee for the Vermont Yankee Nuclear Power Station, submitted for Nuclear Regulatory Commission (NRC) staff review a proposea change to the technical specifications (TS). The licensee proposed a correction involving the calibration of the augmented off-gas system hydrogen monitors. The existing TS states that " hydrogen balance nitroget shall be used as a gas mixture for the calibration of these monitors and the TS should j
require the use of " hydrogen balance air".
2.0 EVALUATION The gaseous radiological waste system collects, processes, and discharges radioactive l
gaseous waste to the atmosphere through the plant stack during normal operation. The system is designed to prevent the release of significant quantities of gaseous and particulate radioactive material from the site under design basis accident conditions. The system design basis also states that adequate safeguards shall be provided against the possible explosion hazard of the hydrogen and oxygen present due to radiolytic decomposition of reactor water.
The off-gas system's hydrogen monitoring instrumentation provides for indication and control of potentially explosive concentrations of hydrogen in the waste gas holdup system. This instrumentation is designed to detect the presence of elevated hydrogen concentration and i
prevent operation with a potentially explosive mixture. The proper calibration of the hydrogen monitors assures the ability to detect and control potentially explosive concentrations of hydrogen gas.
TS Table 4.9.2 requires that the augmented off-gas system's hydrogen monitor be calibrated once each quarter and references note 4 of this table. Note 4 currently states that "The instrument Calibration shallinclude the use of standard gas samples (high range and low range) containing suitable concentrations, hydrogen balance nitrogen, for the detection range of the interest per Specification 3.8.J.1."
9902230127 990212 PDR ADOCK 05000271 P
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I The licensee stated that the hydrogen monitors used in the Vermont Yankee Nuclear Power Stdion off-gas system cannot be properly calibrated with a " hydrogen balance nitrogen" gas mixture. Calibration of the off-gas hydrogen monitors requires a suitable concentration of hydrogen in air, since the presence of oxygen is required in the sample gas to support a catalytic reaction and air is present during normal operation of the system. Therefore, the licensee proposed to change the TS to read " hydrogen balance air".
The staff has reviewed the proposed change and agrees with the licensee's statement that air is required rather than nitrogen to support the catalytic reaction necessary for the calibration of 1
the off-gas hydrogen monitors. The proposed change is therefore acceptable.
3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Vermont State official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendreant involves'no significant increase in the amounts, and no significant change in the types of any effluents that may be released of' site, and that there is no significant increase i.1 individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment d.volves no significant hazards consideration, and there has been no public comment on such finding (63 FR 71975). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set f7tth 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 the amendment.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health ar'd asfety of the public will not be endangereo by operatiori in the proposed manner, (2) such activities will be conducted in compliance with the 3
Commission's regulations, and (3) the issuance of the amendment will not be inimical to the
' common defense and security or to the health and safety of the public.
Principal Contributor: Richard Croteau Date: February 12, 1999 i
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