In the Matter of Consumers Energy Company (Palisades Plant); Exemption

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-255]

In the Matter of Consumers Energy Company (Palisades Plant);

Exemption

I

Consumers Energy Company (the licensee) is the holder of Facility

Operating License No. DPR-20 which authorizes operation of the

Palisades Plant. The Palisades facility is a pressurized-water reactor

located at the licensee's site in Van Buren County, Michigan. The

license provides, among other things, that the facility is subject to

all rules, regulations, and orders of the Commission now or hereafter

in effect.

II

Pursuant to 10 CFR 50.12(a), ``Specific exemptions,'' the

Commission may grant exemptions from the requirements of the

regulations of this part (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 II.G. of 10 CFR Part 50, Appendix J, Option A, defines Type

B tests as ``tests intended to detect local leaks and to measure

leakage across each pressure-containing or leakage-limiting boundary *

* *.'' which includes air lock door seals.

Section III.D.2.(b)(ii) of 10 CFR Part 50, Appendix J, Option A,

requires air locks opened during periods where containment integrity is

not required to undergo a full air lock pressure test at the end of

such periods.

Section III.D.2.(b)(iii) of 10 CFR Part 50, Appendix J, Option A,

requires air locks opened during periods where containment integrity is

required to undergo a full air lock pressure test within 3 days after

being opened.

III

By letters dated January 10, 1996, and February 20, 1997, the

licensee requested an exemption from 10 CFR Part 50, Appendix J, Option

A, Sections III.D.2.(b)(ii) and III.D.2.(b)(iii), for Type B testing of

the emergency escape air lock. Specifically, this exemption would

permit the licensee to perform a door seal contact verification check

in lieu of the final pressure test required by Appendix J following

opening the air lock doors for post-test restoration or seal

adjustment.

The exemption request is necessary due to the original design of

the emergency escape air lock. During special testing in 1992, the

licensee showed that the annulus between the door seals could not be

successfully tested without the door strongback installed even at

pressures as low as 2 psig. This testing, along with information from

the vendor, confirms that between-the-seal pressure testing on the

emergency escape air lock doors cannot be properly measured or

evaluated if the door strongbacks are not installed. Similarly, the

inner door does not fully seal with the reverse-direction pressure of a

full air lock pressure test unless the strongback is installed.

Since the removal of the inner door strongback after pressure

testing requires the outer door to be opened, a between-the-seals test

of the outer door would be required by the regulation. This test would

require the installation of a strongback on the outer door. Further,

full pressure testing or the pressure induced by the strongback may

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cause the seals to take a set. It is therefore necessary to open both

doors (one at a time) after any pressure testing to ensure full seal

contact, and there is a potential need to readjust the seals to restore

seal contact.

As an alternative to a final pressure test required by Appendix J

for verification of door seal functionality, the licensee has proposed

a final door seal contact verification. This seal performance

verification is completed following the full pressure air lock test,

after the removal of the inner door strongback, and just prior to final

closure of the air lock doors. The requested exemption would not affect

compliance with the present requirement to perform a full pressure

emergency escape air lock test at 6-month intervals. It would also not

affect the requirement to perform a full pressure emergency escape air

lock test within 72 hours of opening either door during periods when

containment integrity is required. The seal contact check replaces the

pressure test required by Appendix J for the door opening(s) and/or

seal adjustments associated with restoration from the required full

pressure tests.

The licensee has performed additional low pressure between-the-

seals testing on the escape lock door seals to measure seal leak rates

at low initial pressures and without the door strongbacks installed, to

see if such tests would yield useful results. The tests indicated that

meaningful between-the-seals testing is not possible with the present

design of the escape air lock, without strongbacks installed.

The licensee has also considered possible modifications to the

existing emergency escape air lock doors in an attempt to identify

other methods of complying with the Appendix J requirements. The

modifications that were considered were:

1. Modify the Seal Design or Change the Seal Material

A proposal was received from the air lock vendor to perform testing

of different seal shapes and materials. This was later withdrawn. The

vendor believes, and the licensee concurs, that the seal material and

shape currently in use are reliable and adequate to maintain

containment integrity. Simply changing the seal material or shape would

be unlikely to allow meaningful between-the-seals tests with

strongbacks removed.

2. Perform Door Modifications by Removing the Doors and Altering the

Sealing Surfaces

Minor modifications were considered for the door mechanisms in

conjunction with reconfigured sealing surfaces. This modification has

never been performed by the air lock vendor and would be experimental.

There is no guarantee that these efforts would be successful in

allowing Palisades to perform between-the-seals testing. The cost of

this modification is estimated by the licensee to be roughly equal to

performing an air lock retrofit, as described below.

3. Perform an Air Lock Retrofit Which Would Include Removing and

Replacing the Doors, the Ends of the Bulkhead, and the Door Mechanisms

The doors would be replaced with doors of a design whose seals can

be tested per Appendix J without additional restraint or subsequent

seal restoration. The mechanisms would be updated for smoother

operation but their function would not be altered.

The only viable alternative found was the replacement of the air

lock doors, which the licensee has estimated would cost a minimum of

$700,000. The licensee states that the cost of performing the

modification is not warranted because no increase in plant or public

safety would be realized. The other modifications to the present doors

or seals would not ensure adequate performance improvement for

unrestrained between-the-seals testing.

During its review, the staff questioned whether post-test seal

adjustment or ``fluffing'' was necessary because the door seals were

too old or worn out to rebound properly to their original shape after

leakage rate testing or whether past fluffing had damaged the seals,

such that replacement of the seals could result in acceptable between-

the-seals testing. The licensee's response, dated February 20, 1997,

stated that the seals are replaced approximately every 3 years and that

the seals have not exceeded their service lives. Also, the licensee

stated that fluffing has not damaged the seals, as indicated by

continued successful Type B tests on both the emergency escape air lock

and on the personnel air lock, on whose seals fluffing is also

performed.

The licensee's proposed test methods deviate from the requirements

of Appendix J in two ways:

(1) The seals are not leakage rate tested after opening the doors

for post-test restoration, such as removing the strongbacks; and

(2) The seals are not leakage rate tested after being adjusted

(e.g., fluffed).

The following quotation from American National Standard ANSI/ANS-

56.8-1994, ``Containment System Leakage Testing Requirements,'' is

pertinent. Section 3.3.4.2 states, in part:

An airlock test shall be performed whenever repairs or

adjustments have been performed that affect the leakage rate

characteristics of the airlock. Opening of the airlock for the

purpose of removing airlock testing equipment following an airlock

test does not require further testing of the airlock.

The quoted provisions have been endorsed by the staff through

Regulatory Guide 1.163, ``Performance-Based Containment Leak-Test

Program,'' dated September 1995, for plants following Option B of

Appendix J. Although Palisades follows Option A of Appendix J for Type

B and C leakage tests, in this case the quoted provisions represent a

valid technical position that may be used to help establish a basis for

granting an exemption from the requirements of Option A of Appendix J.

Therefore, concerning deviation (1) described above, the staff's

technical position is that leakage rate testing is not necessary after

opening the doors for post-test restoration. Option A of Appendix J

requires a leakage rate test after opening a door, with the idea that

the door opening is a relatively isolated event. Requiring another test

immediately after a valid test simply because the door was opened again

to remove test equipment is not necessary to meet the intent of the

regulation, especially if it leads to an infinite series of tests, as

in this case. Thus, deviation (1) is acceptable as part of an exemption

from Option A of Appendix J.

Concerning deviation (2) above, there is considerable evidence that

post-test seal adjustment should not necessitate a follow-up leakage

rate test in this case. The present practice ensures proper door seal

contact prior to final door closure. The performance of this door seal

contact check has led to the successful completion of subsequent

emergency escape air lock full pressure tests since the procedural

practice began in 1987. Also, no ILRT in that period has failed because

of emergency escape air lock door seal leakage. Based on these results,

the air lock doors have been proven to function as designed using

current methods of testing and maintenance, including seal contact

checks. Alternatives would only provide approximately the same level of

protection for public health and safety as currently exists. Continuing

with the current methods of testing will not result in undue risk to

public health and safety and is consistent with the common defense and

security. Further,

[[Page 53031]]

the underlying purpose of between-the-seals testing is to verify the

seal integrity after an air lock door is opened or its seals adjusted.

The seal contact check performed on the emergency escape air lock door

seals serves this purpose and ensures the doors are sealing properly.

Therefore, application of the regulation to perform between-the-seals

leakage rate tests after seal adjustment is not necessary in this case

to achieve the underlying purpose of the rule.

IV

Accordingly, the Commission concludes that the licensee's proposal

to perform seal contact testing instead of Type B leakage rate between-

the-seals testing on the emergency escape air lock door seals is

acceptable. There is reasonable assurance that the containment leakage

limiting function will be maintained.

The licensee's request cites the special circumstances of 10 CFR

50.12, Sections (a)(2)(ii) and (a)(2)(iii), as the basis for the

exemption. Appendix J to 10 CFR Part 50 requires full pressure tests

following air lock door openings. The licensee stated that the proposed

alternate seal contact verification check will ensure that the air lock

doors are sealing properly. The licensee also stated that the only

viable alternative to the proposed exemption would be to perform an air

lock retrofit that would involve a significant cost to the licensee.

The Commission concludes that the special circumstances of 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.

V

Accordingly, the Commission has determined, pursuant to 10 CFR

50.12(a), that this exemption is authorized by law, 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

justifying the exemption.

Therefore, the Commission hereby grants the exemption from 10 CFR

Part 50 Appendix J, Option A, Sections III.D.2.(b)(ii) and

III.D.2.(b)(iii), to the extent that leakage rate testing is not

necessary after opening the emergency escape air lock doors for post-

test restoration or post-test adjustment of the airlock door seals.

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 (62 FR 34720).

This exemption is effective upon issuance.

Dated at Rockville, Maryland, this 30th day of September 1997.

For the Nuclear Regulatory Commission.

Frank J. Miraglia,

Acting Director, Office of Nuclear Reactor Regulation.

[FR Doc. 97-26991 Filed 10-9-97; 8:45 am]

BILLING CODE 7590-01-P