01-19972. STP Nuclear Operating Company, et al., South Texas Project, Units 1 and 2; Exemption

1.0 Background

STP Nuclear Operating Company, et al. (STPNOC or the licensee) is the holder of Facility Operating License Nos. NPF-76 and NPF-80, which authorize operation of the South Texas Project, Units 1 and 2 (STP or the facilities). The licenses provide, among other things, that the licensee is subject to all rules, regulations, and orders of the U.S. Nuclear Regulatory Commission (NRC or the Commission) now or hereafter in effect.

The facilities consist of two pressurized-water reactors located at the licensee's site in Matagorda County, Texas.

2.0 Request/Action

Section 50.34(b)(10) of Title 10 of the Code of Federal Regulations part 50 [10 CFR 50.34(b)(10)], states for operating license holders whose construction permit was issued prior to January 10, 1997, that the earthquake engineering criteria in Section VI of Appendix A to 10 CFR part 100 continues to apply. For operating license holders whose construction permit was issued prior to January 10, 1997, 10 CFR 50.34(b)(11) states that the reactor site criteria in 10 CFR part 100, and seismic and geological siting criteria in Appendix A to 10 CFR part 100 continues to apply. Section VI.(a)(1) of Appendix A to 10 CFR part 100, requires that those structures, systems, and components (SSCs) that are necessary to assure (1) the integrity of the reactor coolant pressure boundary, (2) the capability to shut down the reactor and maintain it in a safe condition, or (3) the capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposures shall remain functional during a safe shutdown earthquake (SSE). Further, in addition to seismic loads, including aftershocks, these SSCs shall be designed to take into account applicable concurrent functional and accident-induced loads. Section VI.(a)(2) of Appendix A to 10 CFR part 100, requires that all SSCs of the nuclear power plant necessary for continued operation without undue risk to the health and safety of the public shall be designed to remain functional and within applicable stress and deformation limits when subject to the effects of the vibratory motion of the operating basis earthquake (OBE) in combination with normal operating loads. Both Sections VI.(a)(1) and (2) provide a description of the methods for seismically qualifying these SSCs. These methods involve either a suitable dynamic analysis or a suitable qualification test to demonstrate that the SSCs can withstand the seismic and other concurrent loads, except where it can be demonstrated that the use of an equivalent static load method provides adequate conservatism.

By letter dated July 13, 1999, as supplemented October 14 and 22, 1999, January 26 and August 31, 2000, and January 15, 18, 23, March 19, May 8 and 21, 2001, (hereinafter, the submittal), the licensee requested an exemption from the testing and specific types of analyses required to demonstrate that SSCs are designed to withstand the SSE and OBE for those safety-related SSCs that are categorized in accordance with its risk-informed categorization process as low safety significant (LSS) or non-risk significant (NRS). The licensee would not maintain safety-related LSS and NRS components in a seismically qualified condition in accordance with the requirements specified in 10 CFR part 100. Further, the licensee could replace a safety-related LSS or NRS SSC with an SSC that is not seismically qualified in accordance with the requirements specified in 10 CFR part 100.

3.0 Discussion

There are no specific provisions in 10 CFR part 100 for granting exemptions. However, the licensee has also requested an exemption from 10 CFR 50.34(b)(10) and 10 CFR 50.34(b)(11), which can be granted provided the provisions of 10 CFR 50.12 are met. As discussed in the August 3, 2001, safety evaluation (SE) prepared in support of this exemption, the staff determined it is consistent with Commission policy to apply the exemption provisions of 10 CFR 50.12 to exemptions from the requirements of 10 CFR part 100, Appendix A, Sections VI.(a)(1) and (2) to the extent requested by the licensee. The staff informed the Commission of the decision to apply the requirements of 10 CFR 50.12 to the exemptions requested from Appendix A to 10 CFR part 100, Sections VI.(a)(1) and VI.(a)(2), during the Commission meeting on July 20, 2001.

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. Under 10 CFR 50.12(a)(2)(vi), special circumstances are present whenever there is any other material circumstances not considered when the regulation was adopted for which it would be in the public interest to grant an exemption. If 10 CFR 50.12(a)(2)(vi) is relied on exclusively for satisfying the special circumstances provision of 10 CFR 50.12(a)(2), the exemption may not be granted until the Executive Director for Operations has consulted with the Commission.

The NRC has completed its evaluation of STPNOC's request for an exemption from the requirements of 10 CFR 50.34(b)(10), 10 CFR 50.34(b)(11), Section VI.(a)(1) of Appendix A to 10 CFR part 100, and Section VI.(a)(2) of Appendix A to 10 CFR part 100. The design aspects of these regulations would continue to apply, that is, the design requirements related to the capability of the SSCs to remain functional considering SSE and OBE seismic loads shall be maintained and must be included as a design requirement or procurement requirement of replacement SSCs. The NRC's findings are documented in a SE dated August 3, 2001, prepared in support of the requested exemption.

The staff has reviewed STPNOC's integrated SSC categorization process. The categorization process was found to use both a probabilistic and a deterministic based methodology that appropriately addressed the issues of defense-in-depth, safety margins, and aggregate risk impacts. The staff finds the proposed categorization process to be acceptable to categorize the risk significance of both functions and SSCs for use in reducing the scope of SSCs subject to special treatment. The categorization process provides an acceptable method for defining those SSCs for which exemptions from the special treatment requirements can be granted. In support of its finding on the licensee's categorization process, the staff also found that the alternative treatment practices provide the licensee with a framework that, if effectively implemented, will provide reasonable confidence that safety-related LSS and NRS SSCs remain capable of performing their safety functions under design-basis conditions. Based on these findings, the staff determined that LSS and NRS SSCs could be excluded from the scope of 10 CFR 50.34(b)(10), 10 CFR 50.34(b)(11), Section VI.(a)(1) of Appendix A to 10 CFR part 100, and Section VI.(a)(2) of Appendix A to 10 CFR part 100, without undue risk to public health and safety.

The staff also found that granting of this exemption is in the public interest in that it enhances the effectiveness and efficiency of the NRC's oversight of the licensee's activities at STP by focusing its resources on those SSCs that are most significant to maintaining public health and safety. Likewise, the licensee's resources and attention can be focused on those SSCs that have the highest contribution to plant risk. Further, the licensee's categorization process provides a method for establishing a licensing basis for STP that is consistent with the risk-informed approach in the NRC's reactor oversight process. This enhances the regulatory framework under which STPNOC operates its facility and by which the NRC oversees the licensee's activities.

As discussed further in the August 3, 2001, SE prepared in support of this exemption, the NRC has concluded that the special circumstances of 10 CFR 50.12(a)(2)(vi) are satisfied in that the licensee has presented a material circumstance (the categorization process) that was not considered when the regulations were adopted and that provides an acceptable method for refining the scope of SSCs to include under the regulations. Furthermore, it is in the public interest to grant such exemptions. Finally, as required by 10 CFR 50.12(a)(2)(vi), the Executive Director for Operations has consulted with the Commission in the application of this special circumstance during the Commission meeting held on July 20, 2001.

4.0 Conclusion

Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12(a), the exemption is authorized by law, will not endanger life or property or common defense and security, and is, otherwise, in the public interest. Also, special circumstances are present. Therefore, the Commission hereby grants, subject to the conditions described below, STPNOC the exemption from 10 CFR 50.34(b)(10), 10 CFR 50.34(b)(11), and Sections VI.(a)(1) and VI.(a)(2) of Appendix A to 10 CFR part 100, to the extent that these regulations require testing and specific types of analyses to demonstrate that SSCs are designed to withstand the SSE and OBE for those safety-related SSCs categorized as LSS or NRS at STP. As conditions of this exemption:

1.The licensee described the categorization, treatment, and oversight (evaluation and assessment) processes in its submittal dated July 13, 1999, as supplemented October 14 and 22, 1999, January 26 and August 31, 2000, and January 15, 18, 23, March 19, May 8 and 21, 2001. The licensee has documented these processes in a proposed Final Safety Analysis Report (FSAR) submittal dated May 21, 2001, found acceptable by the staff as the regulatory basis for granting this exemption (see the NRC's SE dated August 3, 2001). The licensee shall incorporate this proposed FSAR submittal into the STP FSAR and shall implement the categorization, treatment, and oversight processes consistent with the STP FSAR descriptions.

2.The licensee shall implement a change control process that incorporates the following requirements:

a. Changes to FSAR Section 13.7.2, “Component Categorization Process,” dated May 21, 2001, and found acceptable by the NRC as described in the NRC's SE dated August 3, 2001, may be made without prior NRC approval, unless the change would decrease the effectiveness of the process in identifying high safety significant and medium safety significant components.

b. Changes to FSAR Section 13.7.3, “Treatment of Component Categories,” dated May 21, 2001, and found acceptable by the NRC as described in the NRC's SE dated August 3, 2001, may be made without prior NRC approval, unless the change would result in a reduction in the assurance of component functionality.

c. Changes to FSAR Section 13.7.4, “Continuing Evaluations and Assessments,” dated May 21, 2001, and found acceptable by the NRC as described in the NRC's SE dated August 3, 2001, may be made without prior NRC approval, unless the change would result in a decrease in effectiveness of the evaluations and assessments.

d. The licensee shall submit a report, as specified in 10 CFR 50.4, of changes made without prior NRC approval pursuant to these provisions. The report shall identify each change and describe the basis for the conclusion that the change does not involve a decrease in effectiveness or assurance as described above. The report shall be submitted within 60 days of the date of the change.

e. Changes to FSAR Sections 13.7.2, 13.7.3, and 13.7.4 that do not meet the criteria of a through c above shall be submitted to the NRC for prior review and approval.

Pursuant to 10 CFR 51.32, an environmental assessment and finding of no significant impact has been prepared and published in the Federal Register (66 FR 32397). Accordingly, based upon the environmental assessment, the Commission has determined that the granting of this exemption will not have a significant effect on the quality of the human environment.This exemption is effective upon submittal of a FSAR update pursuant to 10 CFR 50.71(e) incorporating the FSAR Sections described in the conditions above.

Dated at Rockville, Maryland, this 3rd day of August, 2001.

For the Nuclear Regulatory Commission.

John A. Zwolinski,

Director, Division of Licensing Project Management, Office of Nuclear Reactor Regulation.