AmerGen Energy Company, LLC (the licensee), is the holder of Facility Operating License No. DPR-16, which authorizes operation of the Oyster Creek Nuclear Generating Station (OCNGS).
The facility consists of a boiling-water reactor (BWR), located in Ocean County, New Jersey. The license provides, among other things, that the facility is subject to all rules, regulations, and orders of the Nuclear Regulatory Commission (NRC, the Commission) now or hereafter in effect.
Title 10 of the Code of Federal Regulations (10 CFR) part 50, Appendix J, Option B, Section III.B., “Type B and C Tests,” states, in part, that containment leakage tests must demonstrate that the sum of the leakage rates at accident pressure of Type B tests, and pathway leakage rates from Type C tests, is less than the performance criterion (La) with margin as specified in the Technical Specifications (TSs). In this context, “accident pressure,” Pa, was previously analyzed to be 35 psig at OCNGS. Accordingly, for main steam isolation valves (MSIVs), leakage rate testing is to be done at this peak containment calculated pressure, i.e., 35 psig.
By letter dated December 23, 2003, the licensee requested a permanent exemption from the requirements of the subject provision of Appendix J, such that the MSIVs may be tested at lower pressures but not lower than 20 psig. By separate application also dated December 23, 2003, the licensee proposed to revise the OCNGS TSs, Section 4.5.D, to specify the lower test pressure and leakage rate; the NRC staff will communicate the results of its review of this proposed license amendment by separate correspondence.
In summary, in order for the NRC staff to approve the lower leakage rate test pressure for the TSs, the licensee first needs an exemption from the subject regulation.
Pursuant to 10 CFR 50.12, the Commission may, upon application by any interested person or upon its own initiative, grant exemptions from the requirements of 10 CFR part 50 when (1) the exemptions are authorized by law, will not present an undue risk to public health or safety, and are consistent with the common defense and security; and (2) when special circumstances are present. These circumstances include situations where the regulation would not serve the underlying purpose of the rule.
OCNGS has two main steam lines, each having two MSIVs. The MSIVs are 24-inch angled globe valves of “Y” configuration. The cup-shaped poppet moves on a centerline that is 45 degrees upward from the horizontal centerline of the piping run. Each MSIV is oriented to provide effective sealing in the direction of post-accident containment atmosphere leakage, i.e., the forward direction, as compared to the between-the-valve Type C test which tends to unseat the inboard valve. The design of the steam lines is such that the preferred method of Type C testing is through the use of a between-the-valves test tap. Periodic Type C testing verifies that the leakage assumed in the radiological analysis is not exceeded. The licensee is requesting this exemption and associated amendment to the TSs in order to reduce the probability of lifting the inboard MSIVs during testing. Testing of the two MSIVs simultaneously at Pa, by pressurizing between the valves tends to lift the disc of the inboard valve. This results in test results which may not accurately reflect the isolation capabilities of the MSIVs. Therefore, testing the two MSIVs simultaneously at Pa does not serve the underlying purpose of the rule.
In conjunction with the proposed exemption, the licensee proposed an amendment to the TSs, specifying testing at a minimum of 20 psig between the 2 MSIVs, and an acceptance pathway leakage rate of 11.9 standard cubic feet per hour. The proposed 20 psig pressure is greater than one-half of Pa, and the licensee stated that it would avoid lifting the disc of the inboard valve. As shown in the OCNGS Updated Final Safety Analysis Report, Figure 6.2-3, the primary containment pressure following a design-basis loss-of-coolant accident reaches its peak within 2 to 3 seconds, and rapidly drops below 20 psig. The NRC staff has previously approved testing of MSIVs at reduced pressure at many other BWR plants. Industry experience in testing these valves at a pressure in the range of 20 psig and with an acceptance criterion of approximately 11.9 standard cubic feet per hour has been shown to be effective in determining the condition of these valves.
The underlying purpose of the requirements of 10 CFR part 50, Appendix J, Option B, Section III.B is to demonstrate by periodic testing that the primary reactor containment will be able to perform its function of providing a leak-tight barrier against uncontrolled release of radioactivity to the environment. As stated above, the NRC staff examined the licensee's rationale to support the exemption and concluded that MSIV leakage testing at accident pressure does not serve the underlying purpose of the rule, and fulfillment of the proposed alternative testing criteria would demonstrate leak-tightness of the MSIVs. Thus, the underlying purpose of the subject regulation is achieved and served by the licensee's proposed criteria.
Based upon a consideration of the information submitted by the licensee, the NRC staff concludes that the licensee's proposed reduced test pressure for Type C testing of MSIVs is justified.
Therefore, the NRC staff concludes that pursuant to 10 CFR 50.12(a)(2), special circumstances are present in that application of the Appendix J Start Printed Page 64983requirements does not serve the underlying purpose of the rule.
Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12(a), the exemption is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. Also, special circumstances are present. Therefore, the Commission hereby grants the licensee an exemption from the requirements of 10 CFR part 50, Appendix J, Option B, Section III.B for OCNGS. Specifically, this permanent exemption permits the licensee to perform leakage testing of the MSIVs at reduced pressure, but not lower than 20 psig.
This exemption is effective upon issuance.Start Signature
Dated at Rockville, Maryland, this 2nd day of November, 2004.
For the Nuclear Regulatory Commission.
Ledyard B. Marsh,
Director, Division of Licensing Project Management, Office of Nuclear Reactor Regulation.
[FR Doc. 04-24888 Filed 11-8-04; 8:45 am]
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