[Federal Register Volume 60, Number 52 (Friday, March 17, 1995)]
[Notices]
[Pages 14468-14470]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-6616]



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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-373 50-374


Exemption

    In the Matter of Commonwealth Edison Co., LaSalle County 
Station, Units 1 and 2.

I

    Commonwealth Edison Company (ComEd, the licensee) is the holder of 
Facility Operating License Nos. NPF-11 and NPF-18, which authorize 
operation of the LaSalle County Station, Units 1 and 2 (the facility), 
at a steady state power level not in excess of 3323 megawatts thermal. 
The facility consists of two boiling water reactors at the licensee's 
site located in LaSalle County, Illinois. The licenses provide, among 
other things, that they are subject to all rules, regulations, and 
orders of the U.S. Nuclear Regulatory Commission (the Commission) now 
or hereafter in effect.

II

    Section III.A.6(b) of Appendix J to 10 CFR Part 50 states the 
following in regard to performing Overall Integrated Containment 
Leakage Rate (Type A) Tests (ILRT):

    If two consecutive periodic Type A tests fail to meet the 
applicable acceptance criteria in III.A.5(b), notwithstanding the 
periodic retest schedule of III.D., a Type A test shall be performed 
at each plant shutdown for refueling or approximately every 18 
months, whichever occurs first, until two consecutive Type A tests 
meet the acceptance criteria in III.A.5(b), after which time the 
retest schedule specified in III.D. may be resumed.

    The Type A tests performed during the first, third and fourth 
refueling outages for LaSalle County Station, Unit 2, were considered 
to be failures in the ``as-found'' condition due to penalties incurred 
as a result of leakage measured in Type B and C local leak rate tests 
(LLRT). Pursuant to Section III.A.6(b) of Appendix J, Type A testing 
was performed during the fifth refueling outage for LaSalle County 
Station, Unit 2, in December 1993. That Type A test satisfied the ``as-
found'' acceptance criteria. Section III.A.6(b) of Appendix J requires 
an additional Type A test during the sixth refueling outage, currently 
scheduled for February 1995, in order to fulfill the condition of two 
consecutive successful tests prior to resuming the Type A test interval 
of Section III.D.
    As an alternative to performing the required Type A test, the 
licensee has submitted a Corrective Action Plan to address excessive 
local leakage in accordance with the guidance provided in NRC 
Information Notice 85-71, ``Containment Integrated Leak Rate Tests,'' 
dated August 22, 1985. The Corrective Action Plan is in lieu of the 
increased test frequency required by Section III.A.6(b) and, therefore, 
an exemption from this requirement is needed.
    Section III.D.1(a) of Appendix J requires ``* * * a set of three 
Type A tests shall be performed, at approximately equal intervals 
during each 10-year service period. The third test of each set shall be 
conducted when the plant is shutdown for the 10-year plant inservice 
inspections.'' The last refueling outage for Unit 2 during the first 
10-year inservice inspection period is the sixth refueling outage 
scheduled for February 1995. Therefore, in addition to the requirements 
for additional testing specified in Section III.A.6(b), a Type A test 
is required during the upcoming Unit 2 refueling outage as a result of 
the periodic retest schedule contained in Section III.D.1(a). To 
address the short-term desire not to perform a Type A test during the 
sixth refueling outage for Unit 2 and avoid potential future problems, 
the licensee has requested an exemption from this requirement such that 
future Type A test would not need to coincide with the end of 10-year 
inservice inspection periods.
    The NRC may grant exemptions from the requirements of the 
regulations, pursuant to 10 CFR 50.12, that (1) 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) present 
special circumstances. Section 50.12(a)(2) of 10 CFR Part 50 describes 
special circumstances as including cases that would not serve the 
underlying purpose of the rule or are not necessary to achieve the 
underlying purpose of the rule.

III

    The underlying purpose of the requirements in Appendix J is to 
ensure that containment leakage remains below criteria established to 
limit the release of radioactive materials in the event of a design 
basis accident. The Type A test is defined in 10 CFR Part 50, Appendix 
J, Section II.F, as a ``test intended to measure the primary reactor 
containment overall integrated leakage rate (1) after the containment 
has been completed and is ready for operation, and (2) at periodic 
intervals thereafter.'' Containment leakage is measured during the 
periodic testing required by Section III.D.1(a) and the additional 
testing requirements of Section III.A.6 if the measured leakage exceeds 
the established limits. The testing and other requirements contained in 
Appendix J ensure that leakage from the containment structure and 
penetrations remain below the acceptance criteria.
    The licensee conducted four ILRTs during the first 10-year service 
period for Unit 1. For Unit 2, ILRTs were performed during the first, 
third, fourth, and fifth refueling outages. The Type A test history for 
Unit 2 is that the measured leakage rates for Type B and C 
penetrations, when added to the measured results from the Type A test, 
resulted in an ``as-found'' integrated leakage rate above the 
acceptance criteria. These test failures were the direct result of 
leakage penalties from Type B and C LLRTs.
    Leakage from specific containment penetrations that have been major 
contributors to the failure of the integrated leakage rate acceptance 
criteria for Unit 2 have been identified. These leakage paths include 
isolation valves associated with the drywell equipment and floor drain 
sumps, reactor water cleanup suction, transversing incore probe air 
purge supply, residual heat removal shutdown cooling return, hydrogen 
recombiners, and primary containment chilled water supply. The leakage 
associated with the reactor water cleanup suction penetration provided 
the overwhelming contribution of local leakage penalty that resulted in 
the unsuccessful test during the fourth refueling outage. Leakage 
through the various isolation valves has been attributed to causes 
[[Page 14469]] such as the introduction of foreign materials, 
misapplication of valve types, insufficient seating, defective valve 
internals, and failure of valve motor operators. Specific corrective 
actions have addressed the above contributors by improving foreign 
material exclusion controls, replacing and refurbishing valves, 
revising test procedures, and cleaning and lapping seating surfaces. 
Overall performance of the identified penetrations has improved 
significantly.
    In addition to the specific corrective actions taken for the above 
isolation valves, the licensee's Corrective Action Plan includes 
programmatic changes to limit the leakage occurring from Type C 
penetrations. These changes include development and implementation of 
an improved trending program to track penetration and valve leakage 
rate performance. The improved trending will be designed to help 
determine any patterns or groups of valves that demonstrate either good 
or poor leakage behavior. Those penetrations determined to be 
susceptible to excessive leakage will also be subject to additional 
testing requirements beyond that routinely performed during refueling 
outages. Identified penetrations will be subject to Type B or C testing 
during any non-refueling outage for which a unit is in cold shutdown 
for fourteen days or longer. Poorly performing penetrations will also 
be reviewed for possible improvements in testing methods as well as 
possible repair, modification, or replacement of isolation devices.
    As discussed in Information Notice 85-71, the staff has determined 
that:

    * * * if Type B and C leakage rates constitute an identified 
contributor to this failure of the ``as-found'' condition for the 
Type A test, the general purpose of maintaining a high degree of 
containment integrity might be better served through an improved 
maintenance and testing program for containment penetration 
boundaries and isolation valves. In this situation, the licensee may 
submit a Corrective Action Plan with an alternative leakage test 
program proposals as an exemption request for NRC staff review. If 
this submittal is approved by the NRC staff, the licensee may 
implement the corrective action and alternative leakage test program 
in lieu of the required increase in Type A test frequency incurred 
after the failure of two successive Type A test.

    The licensee's Corrective Action Plan describes the modification, 
testing and preventive maintenance programs implemented or planned to 
decrease the leakage from poorly performing isolation devices. The 
specific corrective actions performed to date and the programmatic 
changes associated with ensuring future performance of penetrations 
provide an equivalent degree of assurance that containment integrity 
will be maintained as that provided by an additional Type A test 
performed on the accelerated frequency specified by Section III.A.6(b) 
of Appendix J. The NRC staff concludes that a return to the normal 
retest interval of Section III.D of Appendix J is justified and that 
the corrective actions taken and the creation of the Corrective Action 
Plan for local leak rate testing adequately address the underlying 
purpose of the requirements of Appendix J.
    In the absence of the additional testing requirements of Section 
III.A.6(b), a periodic retest schedule is specified in section 
III.D.1(a). This retest schedule requires a minimum of three tests 
during a 10-year service period with the third test coinciding with the 
10-year plant inservice inspections. LaSalle, Unit 1, completed four 
tests during the first ten year interval with the last test coinciding 
with the 10-year plant inservice inspections. Due to experiencing Type 
A test failures, Unit 2 has performed four tests during the first 10-
year service period and without the requested exemptions would be 
required to perform a fifth Type A test during the sixth refueling 
outage. The sixth refueling outage for Unit 2 is the last refueling 
outage of the 10-year inservice inspection period and, therefore, the 
Type A test is required based on the requirements of Section III.D.1(a) 
as well as the previously discussed requirements of Section III.A.6(b).
    Pursuant to Section II.F of Appendix J, the intent of Type A 
testing is ``* * * to measure the primary reactor containment overall 
integrated leakage rate * * * at periodic intervals. * * *'' The 
licensee has conducted a total of eight ILRTs for LaSalle, Units 1 and 
2. The tests conclude that the largest variations in the measured 
overall leak rates result from the adjustments required to account for 
leakage from Type B and C penetrations. Leakage from sources other than 
those covered by Type B and C testing, such as the containment 
structure itself, have repeatedly been well below the acceptance 
criteria. The requested exemption from Section III.D.1(a) does not 
affect the performance of local leak rate testing which would be 
expected to detect the most probable sources of containment leakage. As 
discussed above, the licensee will not only continue routine Type B and 
C testing during each refueling outage, but will also attempt to 
minimize local leakage in accordance with their Corrective Action Plan.
    The proposed exemption from Section III.D.1(a) does not revise the 
expected Type A test interval of between thirty and fifty months which 
is derived from the requirement to perform three tests in each ten year 
period at approximately equal intervals. For example, Unit 2 performed 
a Type A test during the fifth refueling outage in December 1993 and, 
with the proposed exemption, will perform another Type A test during 
the seventh refueling outage scheduled to begin in late 1996. The 
licensee has only proposed to exempt the requirement to perform a Type 
A test during the 10-year plant inservice inspections. Given the 
continued performance of Type A testing at approximately equal 
intervals of forty months and the performance of Type B and C testing 
at the required intervals to identify the most probable sources of 
containment leakage, the NRC staff finds that performance of Type A 
tests coincident with 10-year plant inservice inspections is not 
necessary to achieve the underlying purpose of the rule.
    On the bases of the above discussions related to Sections 
III.A.6(b) and III.D.1(a) of Appendix J, the NRC staff finds that the 
licensee has demonstrated that special circumstances are present as 
required by 10 CFR 50.12. Further, the staff finds that providing a 
one-time exemption of the additional testing requirements of section 
III.A.6(b) and an exemption from the requirement to perform a Type A 
test coincident with the first 10-year plant inservice inspections 
pursuant to Section III.D.1(a) will not present undue risk to the 
public health and safety. Although requested as a permanent exemption, 
the exemption from the requirements of section III.D.1(a) of Appendix J 
related to the third test coinciding with the 10-year plant inservice 
inspections has been granted as a one-time exemption for the first 10-
year inservice inspection interval. The exemption is, in effect, 
limited to the Type A test planned for the current Unit 2 outage since 
Unit 1 has completed the required Type A tests during its first 
inservice inspection interval. Future relationships between Appendix J 
and inservice inspection intervals can be addressed by anticipated 
changes to Appendix J or requests for exemptions from the current 
requirements.

IV

    Accordingly, the Commission has determined pursuant to 10 CFR 
50.12, these exemptions are authorized by law and will not endanger 
life or property or the common defense and security and are otherwise 
in the public interest. Therefore, the Commission hereby 
[[Page 14470]] grants an exemption from the additional testing 
requirements of Section III.A.6(b) of Appendix J to 10 CFR Part 50 to 
allow the licensee to resume the Type A test interval of Section III.D 
for LaSalle, Unit 2, and an exemption from the requirements of Section 
III.D.1(a) of Appendix J to allow the licensee to de-couple the Type A 
testing and the first 10-year plant inservice inspections for LaSalle, 
Unit 2.
    Pursuant to 10 CFR 31.32, the Commission determined that the 
granting of this exemption will have no significant impact on the 
quality of the human environment (60 FR 13187).

    Dated at Rockville, Maryland this 10th day of March 1995.

    For the Nuclear Regulatory Commission.
Elinor G. Adensam,
Acting Director, Division of Reactor Projects III/IV, Office of Nuclear 
Reactor Regulation.
[FR Doc. 95-6616 Filed 3-16-95; 8:45 am]
BILLING CODE 7590-01-M