[Federal Register Volume 62, Number 197 (Friday, October 10, 1997)]
[Notices]
[Pages 53029-53031]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-26991]
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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
[[Page 53030]]
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