[Federal Register Volume 61, Number 15 (Tuesday, January 23, 1996)]
[Notices]
[Pages 1787-1788]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-810]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-155]
Consumers Power Company (Big Rock Point Plant); Exemption
I
Consumers Power Company (CPCo, the licensee) is the holder of
Facility Operating License No. DPR-6 which authorizes operation of the
Big Rock Point Plant (the facility). The facility consists of a boiling
water reactor located at the licensee's site in Charlevoix County,
Michigan. The license provides, among other things, that the facility
is subject to all rules, regulations, and orders of the Nuclear
Regulatory Commission (the Commission) now or hereafter in effect.
II
Pursuant to 10 CFR 50.12(a), the NRC may grant exemptions from the
requirements of the regulations (1) which are authorized by law, will
not present an undue risk to the public health and safety, and are
consistent with the common defense and security; and (2) where special
circumstances are present.
Section III.D.1.(a) of Appendix J [Option A] to 10 CFR Part 50
requires the performance of three Type A containment integrated leak
rate tests (ILRTs) at approximately equal intervals during each of the
10-year service periods of the primary containment.
III
By letter dated November 8, 1995, the licensee requested a one-time
schedular exemption from the ``approximately equal time intervals''
requirement of 10 CFR Part 50, Appendix J, Section III.D.1.(a).
Specifically, the proposed exemption would allow CPCo to delay the Type
A test until the January 1997 refueling outage. The interval between
the Type A tests would increase from 47 months to 59 months.
The licensee's request cites the special circumstances of 10 CFR
50.12, paragraph (a)(2)(ii), as the basis for the exemption. In 10 CFR
Part 50 Appendix J, it states that the purpose of the Type A, B, and C
tests is to assure that leakage through the primary containment shall
not exceed the allowable leakage rate values as specified in the
technical specifications or associated bases. CPCo stated that the
existing Type B and Type C tests, which are unaffected by this proposed
change, will continue to detect leakage through containment valves,
penetrations, and airlocks.
The licensee has analyzed the results of previous Type A tests
performed at the Big Rock Point Plant to show adequate containment
performance. The licensee will continue to conduct Type B and Type C
local leak rate tests which historically have been shown to be the
principal means of detecting containment leakage paths with the Type A
tests confirming the Type B and C tests results. It is also noted that
the licensee would perform a general inspection of accessible interior
or exterior surfaces of the containment structures and components
although it is only required by Appendix J to be conducted in
conjunction with Type A tests.
The testing history and structural capability of the containment
establish that there is significant assurance that the extended
interval between Type A tests will not adversely impact the leak-tight
integrity of the containment and that performance of the Type A test is
not necessary to meet the underlying purpose of Appendix J.
The alternative actions proposed by the licensee in the exemption
request provide reasonable assurance that leakage will not exceed
acceptable levels. Therefore, granting this exemption does not present
an undue risk to public health and safety.
The underlying purpose of the requirement to perform Type A
containment test leak rate tests at intervals during the 10-year
service period is to ensure that any potential
[[Page 1788]]
leakage pathways through the containment boundary are identified within
a time span that prevents significant degradation from continuing.
The licensee notes that the results of the Type A testing have been
confirmatory of the Type B and Type C tests which will continue to be
performed. The licensee has stated that it will perform the general
inspection of accessible interior or exterior surfaces of the
containment structures and components although it is only required by
Appendix J to be conducted in conjunction with Type A tests. The NRC
staff considers that these inspections, though limited in scope,
provide an important added level of confidence in the continued
integrity of the containment boundary.
The NRC staff has also made use of the information in a draft staff
report, NUREG-1493, ``Performance-based Containment Leak-Test
Program,'' which provides the technical justification for Option B of
Appendix J which includes a 10-year test interval for Type A tests. The
Type A test measures overall containment leakage. However, operating
experience with all types of containments used in this country
demonstrates that essentially all containment leakage can be detected
by local leak rate tests (Type B and Type C). According to results
given in NUREG-1493, out of 180 ILRT reports covering 110 individual
reactors and approximately 770 years of operating history, only 5 ILRT
failures were found which local leakage rate testing could not detect.
This is 3 percent of all failures. This study agrees well with previous
NRC staff studies which show that Type B and Type C testing can detect
a very large percentage of containment leaks. The Big Rock Point Plant
experience has also been consistent with these results.
The Nuclear Management and Resources Council (NUMARC), now the
Nuclear Energy Institute (NEI), collected and provided the NRC staff
with summaries of data to assist in the preparation of Option B to
Appendix J. NUMARC collected results of 144 ILRTs from 33 units; 23
ILRTs exceeded 1 La. Of these, only nine were not Type B or Type C
leakage penalties. The NEI data also added another perspective. The NEI
data show that in about one-third of the cases exceeding allowable
leakage, the as-found leakage was less than 2 La; in one case the
leakage was found to be approximately 2 La; in one case the
leakage was less than 3 La; one case approached 10 La; and in
one case the as-found leakage was found to be approximately 21 La.
For about half of the failed ILRTs the as-found leakage was not
quantified. These data show that, for those ILRTs for which the leakage
was quantified, the leakage values are small in comparison to the
leakage value at which the risk to the public starts to increase over
the value of risk corresponding to La (approximate 200 La, as
discussed in NUREG-1493). Therefore, based on these considerations, it
is unlikely that an extension of one cycle for the performance of the
Appendix J, Type A test at the Big Rock Point Plant would result in
significant degradation of the overall containment integrity. As a
result, the application of the regulation in these particular
circumstances is not necessary to achieve the underlying purpose of the
rule. Therefore, special circumstances exist pursuant to 10 CFR
50.12(a)(2)(ii).
Thus, the staff concludes that an exemption from the requirements
of paragraph III.D.1(a) of Appendix J to 10 CFR Part 50 should be
granted. The Commission further determines that special circumstances
as provided in 10 CFR 50.12(a)(2)(ii) are present justifying the
exemption; namely, that application of the regulation in the particular
circumstances is not necessary to achieve the underlying purpose of the
rule.
IV
Accordingly, the Commission has determined, pursuant to 10 CFR
50.12, that this exemption is authorized by law, and will not present
an undue risk to the public health and safety, and is consistent with
the common defense and security. The Commission further determines that
special circumstances as provided in 10 CFR 50.12(a)(2)(ii) are present
in that application of the regulation in these particular circumstances
is not necessary to achieve the underlying purpose of the rule.
Therefore, the Commission hereby grants the exemption from 10 CFR
Part 50, Appendix J, Section III.D.1.(a) to the extent that the
Appendix J test interval for performing Type A tests may be extended
one cycle until the January 1997 refueling outage, on a one-time basis
only, for the Big Rock Point Plant, provided that the general
containment inspection is performed and as described in Section III
above.
Pursuant to 10 CFR 51.32, the Commission has determined that
granting this exemption will not have a significant effect on the
quality of the human environment (61 FR 422).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 16th day of January 1996.
For the Nuclear Regulatory Commission.
Jack W. Roe,
Director, Division of Reactor Projects--III/IV, Office of Nuclear
Reactor Regulation.
[FR Doc. 96-810 Filed 1-22-96; 8:45 am]
BILLING CODE 7590-01-P
