[Federal Register Volume 66, Number 154 (Thursday, August 9, 2001)]
[Notices]
[Pages 41906-41907]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-19971]


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NUCLEAR REGULATORY COMMISSION

[Docket No(s). 50-498 and 50-499]


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

    Under Option B of Appendix J to Title 10 of the Code of Federal 
Regulations part 50 (10 CFR part 50, appendix J, Option B) a 
performance based set of testing requirements is provided to ensure 
that leakage through primary reactor containments for water cooled 
power reactors or structures, systems, and components (SSCs) 
penetrating these containments does not exceed allowable leakage rates 
specified in the Technical Specifications and that the integrity of the 
containment structure is maintained during its service life. Also 
required by 10 CFR Part 50, Appendix J, Option B, Section III.B, is 
that ``the sum of the leakage rates at accident pressure of Type B 
tests and pathway leakage rates from Type C tests, must be less than 
the performance criterion (La) with margin, as specified in 
the Technical Specifications.''
    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 10 CFR Part 50, Appendix J, Option B, 
Section III.B, ``Type B and C Tests,'' to the extent that this 
regulation imposes Type C leakage rate testing on certain containment 
isolation valves. The scope of the exemption includes those containment 
isolation valves categorized as low safety significant (LSS) or non-
risk significant (NRS) in accordance with the licensee's categorization 
process and satisfying one or more of the following criteria:
    a. The valve is required to be open under accident conditions to 
prevent or mitigate core damage events.
    b. The valve is normally closed and in a physically closed, water 
filled system.
    c. The valve is in a physically closed system whose piping pressure 
rating exceeds the containment design pressure rating and that is not 
connected to the reactor coolant pressure boundary.
    d. The valve is in a closed system whose piping pressure rating 
exceeds the containment design pressure rating, and is connected to the 
reactor coolant pressure boundary. The process line between the 
containment isolation valve and the reactor coolant pressure boundary 
is non-nuclear safety (i.e., the valve itself would have been 
classified as non-nuclear safety were it not for that fact that it 
penetrates the containment building).
    e. The valve size is 1-inch nominal pipe size or less (i.e., by 
definition the valve failure does not contribute to large early 
release).

3.0  Discussion

    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 the special circumstance of 10 CFR 50.12(a)(2)(vi) is 
relied on exclusively, 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 Type C leakage rate testing requirements of 10 CFR 
part 50, Appendix J, Option B, Section III.B. The NRC's evaluation is 
provided in a safety evaluation (SE), dated August 3, 2001, prepared in 
support of this 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.
    In addition, in determining whether to grant this exemption, the 
NRC reviewed the licensee's submittal and specifically reviewed the 
criteria for excluding containment isolation valves from Type C 
testing. The NRC found that these criteria are reasonable in that even 
without Type C testing the probability of significant leakage during an 
accident (that is, leakage to the extent that public health and safety 
is affected) is small. Based on its review of these criteria, the NRC 
found that the licensee's assumption that these valves contribute zero 
leakage is acceptable. In addition, the NRC reviewed the licensee's 
application of the proposed criteria to the various containment 
isolation valves and found that the licensee was appropriately applying 
the criteria.
    Based on these findings, the staff determined that LSS and NRS 
SSCs, meeting the additional criteria proposed by the licensee for 
containment isolation valves, could be excluded from the scope of Type 
C leakage rate testing required by 10 CFR part 50, Appendix J, Option 
B, Section III.B, 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

[[Page 41907]]

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.
    The licensee has stated that ``STP does not plan to revise the 
allowable leakage values contained in the Technical Specifications * * 
* Those penetrations which have been removed from Appendix J scope by 
this exemption request will be assumed to contribute zero leakage * * 
'' Since the cumulative total applies only to leakage from those leak 
tests that are performed and not the leakage from each penetration, the 
NRC concluded there is no need for an exemption from the requirement 
that ``the sum of the leakage rates at accident pressure of Type B 
tests and pathway leakage rates from Type C tests, must be less than 
the performance criterion (La) with margin, as specified in 
the Technical Specifications.''

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 part 50, Appendix J, Option B, 
Section III.B, to the extent that it imposes Type C testing 
requirements on safety-related containment isolation valves satisfying 
one or more of the criteria specified above, and categorized as LSS or 
NRS at STP. Based on the staff's determination that there is no need 
for an exemption from the requirement that ``the sum of the leakage 
rates at accident pressure of Type B tests and pathway leakage rates 
from Type C tests, must be less than the performance criterion 
(La) with margin, as specified in the Technical 
Specifications,'' the exemption granted does not extent to this 
provision of the regulation. 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 an 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.
[FR Doc. 01-19971 Filed 8-8-01; 8:45 am]
BILLING CODE 7590-01-P