[Federal Register Volume 71, Number 239 (Wednesday, December 13, 2006)]
[Notices]
[Pages 74958-74959]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-21152]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-263]
Nuclear Management Company, LLC; Monticello Nuclear Generating
Plant; Exemption
1.0 Background
Nuclear Management Company, LLC (the licensee), is the holder of
Facility Operating License No. DPR-22 which authorizes operation of
Monticello Nuclear Generating Plant (MNGP). The license provides, among
other things, that the facility is subject to all rules, regulations,
and orders of the U.S. Nuclear Regulatory Commission (NRC, the
Commission) now or hereafter in effect.
The facility consists of a boiling-water reactor located in Wright
County in Minnesota.
2.0 Request/Action
Appendix J to Title 10 of the Code of Federal Regulations (10 CFR)
specifies the leakage rate test requirements, schedules, and acceptance
criteria for tests of the leak-tight integrity of the primary reactor
containment and systems and components that penetrate the containment.
Option B, Paragraph III.A, of Appendix J requires that the overall
integrated leakage rate must not exceed the allowable leakage (La) with
margin, as specified in the plant's Technical Specifications. The
overall integrated leakage rate, as specified in Appendix J, includes
the contribution from main steam pathway leakage (i.e., through the
four main steam lines and the main steam drain line at MNGP). Option B,
Paragraph III.B requires that the sum of the leakage rates of Type B
and Type C local leakage rate tests be less than the performance
criterion (La) with margin, as specified in the Technical
Specifications.
By letter dated September 15, 2005, the licensee requested
exemption from Option B, Section III.A, requirements to exclude main
steam isolation valve (MSIV) leakage from the overall integrated leak
rate test measurement, and exemption from Section III.B requirements to
exclude the MSIV leakage from the sum of the Type B and Type C tests.
The licensee stated that the MNGP MSIV leakage effluent has a different
pathway to the environment when compared to a typical containment
penetration, i.e., it is not directed into the secondary containment
and filtered through the standby gas treatment system. Instead, the
main steam leakage is collected and treated via an alternative leakage
treatment pathway, having different mitigation characteristics.
In performing accident analyses, it is appropriate to group various
leakage effluents according to the treatment they receive before being
released to the environment (e.g., from main steam pathways).
Accordingly, the licensee's proposed exemption from the Appendix J
requirements would more appropriately reflect the MNGP design which
employs an alternative leakage treatment pathway. The calculated
radiological consequences of the combined leakages were found to be
within the criteria of 10 CFR 50.67 and GDC-19. The NRC staff reviewed
the licensee's analyses and found them acceptable as described in a
safety analysis accompanying an amendment regarding alternative source
term methodology to be issued concurrently with this exemption. By
separating the MSIV leakage acceptance criteria from the overall
integrated leak rate test criteria, and from the Type B and C leakage
sum limitation, the MNGP containment leakage testing program will be
made more consistent with the limiting assumptions used in the
associated accident consequences analyses. The amendment associated
with this exemption will revise Technical Specification Surveillance
Requirement 3.6.1.3.13 to limit the maximum allowable combined MSIV
leakage to 200 standard cubic feet per hour, which is the analytical
limit.
Based on the foregoing, the separation of the main steam pathways
from the other containment leakage pathways is warranted because a
separate radiological consequence term has been provided for these
pathways. The revised design basis radiological consequence analyses
address these pathways as individual factors, exclusive of the primary
containment leakage.
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. The licensee's exemption
request was submitted in conjunction with an amendment application to
employ the alternative source term (AST) methodology for design-basis
accidents. The NRC staff had completed its review and is issuing the
proposed amendment on the same date as this exemption. The exemption
and amendment together would implement the AST methodology. The special
circumstances associated with MSIV leakage testing are fully described
in the licensee's September 15, 2005, application for amendment and
exemption.
Authorized by Law
This exemption would exempt Nuclear Management Company from
requirements in 10 CFR Part 50, Appendix J, thus (1) Excluding MSIV
leakage in the overall integrated leakage rate test measurement
required by Section III. A of Appendix J, Option B; and (2) excluding
the sum of local leak rate test measurements required by Section III.B
of Appendix J, Option B. As stated above, 10 CFR 50.12 allows the NRC
to grant exemptions from the requirements of 10 CFR Part 50. The NRC
staff has determined that granting of the licensee's proposed exemption
will not result in a violation of the Atomic Energy Act of 1954, as
amended, or the Commission's regulations. Therefore, the exemption is
authorized by law.
No Undue Risk to Public Health and Safety
The proposed exemption affects only the radiological dose analysis
models and the way containment leak-tightness is measured. No new
accident precursors are created by the exemption; accordingly, the
probability of postulated accidents is not increased and the
consequences of postulated accidents are not increased. Therefore,
there is no undue risk to public health and safety as a result of the
exemption.
[[Page 74959]]
Consistent With Common Defense and Security
The proposed exemption, as set forth above, would only affect the
radiological dose analysis models and the way containment leak-
tightness is measured. Thus, this exemption bears no relation to
security issues. Therefore, the common defense and security is not
impacted by this exemption.
Special Circumstances
Special circumstances, in accordance with 10 CFR 50.12(a)(2)(ii),
are present whenever application of the regulation in the particular
circumstances ``would not serve the underlying purpose of the rule or
is not necessary to achieve the underlying purpose of the rule.'' The
underlying purpose of Appendix J is to assure that containment leak-
tight integrity is maintained as tight as reasonably achievable, and
sufficiently tight so as to limit effluent release to values bounded by
the analyses of radiological consequences of design-basis accidents.
The NRC staff has determined that the intent of the rule is not
compromised by the licensee's proposed action because containment leak
rates will continue to be limited by MNGP's Technical Specifications.
Therefore, since the underlying purpose of Appendix J is achieved, the
special circumstances required by 10 CFR 50.12(a)(2) for the granting
of an exemption from Appendix J exist.
4.0 Conclusion
Accordingly, the Commission has determined that, pursuant to 10 CFR
50.12, the exemption is authorized by law, will not present an undue
risk to public health and safety, and is consistent with the common
defense and security. Also, special circumstances are present.
Therefore, the Commission hereby grants MNGP an exemption (1) From the
requirements of 10 CFR Part 50, Appendix J, Option B, Paragraph III.A,
to allow exclusion of the main steam pathway leakage from the overall
integrated leakage rate measured when performing a Type A test; and (2)
from the requirements of 10 CFR Part 50, Appendix J, Option B,
Paragraph III.B, to allow exclusion of the main steam pathway leakage
from the combined leakage rate of all penetrations and valves subject
to Type B and C tests.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will not have a significant effect on the
quality of the human environment (71 FR 70996).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 7th day of December, 2006.
For the Nuclear Regulatory Commission.
Cathy Haney,
Director, Division of Operating Reactor Licensing, Office of Nuclear
Reactor Regulation.
[FR Doc. E6-21152 Filed 12-12-06; 8:45 am]
BILLING CODE 7590-01-P