Exemption

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