Entergy Operations, Inc., Arkansas Nuclear One, Unit 2, 3260-3264 [2015-01032]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 80, Number 14 (Thursday, January 22, 2015)]
[Notices]
[Pages 3260-3264]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2015-01032]


=======================================================================
-----------------------------------------------------------------------

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-368; NRC-2015-0008]


Entergy Operations, Inc., Arkansas Nuclear One, Unit 2

AGENCY: Nuclear Regulatory Commission.

ACTION: Exemption; issuance.

-----------------------------------------------------------------------

SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing an 
exemption in response to a January 21, 2014, request from Entergy 
Operations, Inc. (Entergy or the licensee), from certain requirements 
to perform Type B testing (seal pressure test) of the containment 
emergency escape air lock doors. This exemption would permit the 
licensee to perform a door seal contact verification check in lieu of 
the currently required seal pressure test.

DATES: January 22, 2015.

ADDRESSES: Please refer to Docket ID NRC-2015-0008 when contacting the 
NRC about the availability of information regarding this document. You 
may obtain publicly-available information related to this document 
using any of the following methods:
     Federal Rulemaking Web site: Go to https://www.regulations.gov and search for Docket ID NRC-2015-0008. Address 
questions about NRC dockets to Carol Gallagher; telephone: 301-287-
3422; email: Carol.Gallagher@nrc.gov. For technical questions, contact 
the individual listed in the FOR FURTHER INFORMATION CONTACT section of 
this document.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly-available documents online in the 
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and 
then select ``Begin Web-based ADAMS Search.'' For problems with ADAMS, 
please contact the NRC's Public Document Room (PDR) reference staff at 
1-800-397-4209, 301-415-4737, or by email to pdr.resource@nrc.gov. The 
ADAMS accession number for each document referenced in this document 
(if that document is available in ADAMS) is provided the first time 
that a document is referenced.
     NRC's PDR: You may examine and purchase copies of public 
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 
Rockville Pike, Rockville, Maryland 20852.

FOR FURTHER INFORMATION CONTACT: Andrea George, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington DC 
20555-0001; telephone: 301-415-1081, email: Andrea.George@nrc.gov.

SUPPLEMENTARY INFORMATION:

I. Background

    Entergy is the holder of renewed Facility Operating License No. 
NPF-6, which authorizes operation of Arkansas Nuclear One (ANO), Unit 
2. The license provides, among other things, that the facility is 
subject to all rules, regulations, and orders of the NRC now or 
hereafter in effect.
    The ANO facility consists of two pressurized-water reactors, Units 
1 and 2, located in Pope County, Arkansas.

II. Request/Action

    Pursuant to Sec.  50.12 of Title 10 of the Code of Federal 
Regulations (10 CFR), ``Specific exemptions,'' by letter dated January 
21, 2014 (ADAMS Accession No. ML14021A085), as supplemented by letters 
dated March 17 and September 24, 2014 (ADAMS Accession Nos. ML14077A139 
and ML14268A317, respectively), the licensee requested an exemption 
from certain requirements of 10 CFR part 50, Appendix J, ``Primary 
Reactor Containment Leakage Testing for Water-Cooled Power Reactors.'' 
Specifically, the licensee requested an exemption from Option B, 
Section III.B, Type B testing (seal pressure test) of the ANO, Unit 2, 
containment emergency escape air lock doors. This exemption would 
permit the licensee to perform a door seal contact verification check 
in lieu of the currently required seal pressure test.
    Section III.B, Option B, Appendix J, 10 CFR part 50, defines Type B 
tests as pneumatic tests to detect and measure local leakage rates 
across pressure retaining, leakage-limiting boundaries, which include 
containment emergency escape air lock door seals. Section III.B, Option 
B, Appendix J, 10 CFR part 50, also states that these boundaries, such 
as containment emergency escape air locks, must be pneumatically tested 
(1) prior to initial criticality, and (2) periodically thereafter at 
intervals based on the safety significance and historical performance 
of each boundary and isolation valve to ensure the integrity of the 
overall containment system as a barrier to fission product release.
    The licensee stated that the exemption request is necessary due to 
the design characteristics of the ANO, Unit 2, containment emergency 
escape air lock doors, in that the door sealing capability relies, in 
part, on rising containment pressure to provide sufficient closing 
force to produce an effective seal. In order to perform between-the-
seals testing for the doors in the absence of containment pressure, a 
strongback must be installed to simulate this sealing force.

III. Discussion

    Pursuant to 10 CFR 50.12, the Commission may, upon application by 
any interested person or upon its own initiative, grant exemptions from 
the requirements of 10 CFR part 50 when: (1) The exemptions are 
authorized by law, will not present an undue risk to public health or 
safety, and are consistent with the common defense and security; and 
(2) when special circumstances are present. Under 10 CFR 
50.12(a)(2)(ii), special

[[Page 3261]]

circumstances include, among other things, when application of the 
specific regulation in the particular circumstance would not serve, or 
is not necessary to achieve, the underlying purpose of the rule.

A. Special Circumstances

    Special circumstances, in accordance with 10 CFR 50.12(a)(2)(ii), 
are present whenever application of the regulation in the particular 
circumstances is not necessary to achieve the underlying purpose of the 
rule. The underlying purpose of Type B testing in Section III.B, Option 
B, Appendix J, 10 CFR part 50, is to verify containment integrity as a 
fission product barrier to provide reasonable assurance of public 
health and safety in the event of a loss-of-coolant accident. The 
evaluations described in the following sections of this exemption show 
that the underlying purpose of the regulations is met by the proposed 
seal contact check for the ANO, Unit 2, containment emergency escape 
airlock doors. Specifically, due to the design of the doors at ANO, 
Unit 2, the currently required between-the-seals testing (for the 
annulus between the inner and outer emergency air lock doors), if done 
without the strongback installed, is unable to hold pressure at or near 
the Technical Specification (TS) required pressure, and so meaningful 
between-the-seals testing is not possible without installing the 
strongback or exerting significant closing torque to the door closure 
mechanism. The seal contact check, where chalk is applied to the air 
lock door seal face, the door is cycled open and closed, and the chalk 
outline left is representative of the door seal bead mating with the 
seal. If the chalk pattern does not show adequate contact, the seals 
are adjusted and the seal contact test is reperformed until a 360-
degree seal results. The seal contact check and seal adjustments (if 
necessary), the practices for which have been incorporated into ANO, 
Unit 2, maintenance procedures, ensure that the containment emergency 
air lock doors are sealing properly and that seal integrity of the 
doors is maintained. The underlying purpose of Type B testing in 
Section III.B, Option B, Appendix J, 10 CFR part 50, is achieved 
through application of the seal contact check for the air lock doors. 
Therefore, the special circumstances required by 10 CFR 50.12(a)(2)(ii) 
for the granting of an exemption exist.

B. Authorized by Law

    This exemption would allow the use of a seal contact check, in lieu 
of a seal pressure test, to verify the seal tightness of the ANO, Unit 
2, containment emergency escape air lock doors. As stated above, 10 CFR 
50.12 allows the NRC to grant exemptions from the requirements of 10 
CFR part 50 provided that special circumstances are present. As 
described above, the NRC staff has determined that special 
circumstances exist to grant the requested exemption. In addition, 
granting the exemption will not result in a violation of the Atomic 
Energy Act of 1954, as amended, or the Commission's regulations. 
Therefore, the exemption is authorized by law.

C. No Undue Risk to Public Health and Safety

    This exemption request is necessary due to the original design of 
the containment emergency escape air lock at ANO, Unit 2. The air lock 
consists of a steel cylinder with a circular door at each end, an outer 
door and inner door, with the inner door being directly in contact with 
the interior of the containment building. Both of the air lock doors 
open inward toward the containment building interior, and so, during 
between-the-seals pressure testing (between the two air lock doors), 
the increasing pressure tends to more tightly seat the outer air lock 
door and push the inner airlock door off of its seat. The licensee 
stated that though each air lock door is fitted with two latching pins, 
one for the top and one for the bottom, these pins are not designed to 
provide enough closing force for meaningful between-the-seals testing 
without a strongback installed. During a postulated design basis event, 
both air lock doors rely on rising containment building pressure to 
provide closing force for a sufficiently tight seal in order to 
constitute a fission product boundary.
    In its application, the licensee stated that during trial testing, 
the annulus between the door seals could not be successfully tested 
without the door strongback installed, even at pressures as low as 12 
pounds per square inch gauge. This indicates that the leak rates for 
between-the-seals testing on the emergency escape air lock doors cannot 
meet the acceptance criteria found in Section III.B.1.(c), Appendix J, 
10 CFR part 50, without the use of a strongback. The licensee stated 
that it has taken efforts to improve the test without the use of a 
strongback, and that these efforts have produced conflicting results. 
The licensee concluded that a complete change-out of the inner and 
outer bulkhead and door assemblies would be required to support 
incorporating an ``O'' ring seal design with a 3-pin latching 
configuration. Based on vendor information, the ``O'' ring seal design 
is superior to the flat seal profile design. Consideration was also 
given to a gear reduction design for the opening and closing mechanism. 
The licensee stated that while this option would increase sealing 
forces, there is insufficient evidence to determine whether such a 
modification would ensure future success with respect to between-the-
seals pressure testing.
    The licensee stated that in recent years, it has performed 
significant maintenance and modification activities on the air lock 
doors with onsite vendor support. By letter dated August 11, 2014 
(ADAMS Accession No. ML14218A602), the NRC staff submitted a request 
for additional information to the licensee regarding whether seal 
design, seal material, seal shape, and seal operation conditions had 
been evaluated to address the between-the-seals testing difficulties. 
In its response dated September 24, 2014, the licensee stated that the 
following activities have been completed in recent years regarding the 
air locks: (1) Increased door to seal contact by adjusting door 
settings, (2) designed a torque amplifying device to assist in opening/
closing the door due to increasing the contact pressures, (3) replaced 
door seals every refueling outage, (4) upgraded door locking bolt 
compression springs to allow for additional closing forces with 
improved ability to open the doors, (5) replaced locking bolt brackets 
and pins, and (6) obtained vendor support and expertise to maintain and 
adjust the door for optimum performance. The licensee also stated that 
the seal material currently in use is an ethylene-propylene-diamine-
monomer, which is the vendor recommended and qualified material. The 
seals are a square cross-section shape design formed in a continuous 
circle to fit the bulk head frame seal channel. By design of the 
channel, the seal shape is limited. In addition, each door is designed 
with a ``nose/sealing bar'' that provides a continuous protrusion into 
the flat-faced seal for improved sealing contact. These features 
prevent seal design changes without extensive changes to the design and 
hardware of the hatch.
    In its application, the licensee indicated that the vendor has 
clearly stated that the ANO, Unit 2, air lock design does not support 
testing without the use of a strongback and, to meet leak rate limits, 
the airlock's latching mechanism must generate a high latch contact 
such that it will maintain a residual compressive load on the gasket 
greater than the unseating effect produced by the test pressure.

[[Page 3262]]

Adjustment and/or modification of the latch in this manner defeats the 
purpose of the emergency escape air lock since excessive human force 
would be required to open the air lock door in an emergency situation. 
The licensee provided information regarding two events where personnel 
or equipment difficulties precluded the air lock doors from being 
opened or opening as designed. In 2008, after an individual became 
trapped in the air lock due to being unable to open the door, the 
licensee installed a torque amplifying device to assist personnel in 
door opening/closing. In 2012, the air lock outer door required 
mechanical agitation to open, and it was noted that the 3/4-inch 
stainless steel latch pins were bent. Based on efforts to date, the 
licensee has concluded that attempting to apply excessive closing 
torque to the door necessary to overcome the original design 
characteristics is inappropriate.
    The licensee has investigated the potential of substantial 
modifications to the air lock doors in order to meet the current seal 
pressure test requirements and the Occupational Safety and Health 
Administration's requirements. Beyond the many components previously 
replaced, along with spring upgrades to help alleviate the excessive 
force now needed to operate the doors, the licensee has determined 
complete door replacement (retrofit) would be necessary to resolve the 
aforementioned issues and have the ability to perform a meaningful 
between-the-seals pressure test. The licensee stated that vendor 
proposals for door replacement reflect an extremely high estimated 
cost, without any guarantee that such a modification would resolve the 
issue of air lock seal pressure testing. The cost of pursuing such a 
modification is unwarranted because no appreciable increase in nuclear 
or public safety would be realized.
    In its application, the licensee stated that past TS surveillance 
testing for the emergency escape air lock has shown that testing with 
strongbacks in place is successful; however, the pressure applied by 
the strongbacks, or the pressure applied to the outer door during the 
overall air lock pressure test, can cause door seals to take a set that 
reflects the shape of the seal grooves. With strongbacks installed or 
test pressure applied to the air lock barrel, the male portion of the 
door seal (the seal bead) can be pressed into the seal. The seal will 
remain in this compressed condition for the entire test period, causing 
the seal to take a set in the seal groove of the air lock bulkhead. 
After completion of an overall air lock barrel pressure test, both 
doors must be opened to verify proper seal contact with the door seal 
bead in order to ensure that the seals rebound to the pre-test 
condition. During the seal contact check, a seal adjustment may be 
required after testing because the force of the strongbacks on a given 
door and/or the force due to the air lock barrel test pressure on the 
outer door can draw the seal bead on the doors further into the seal 
groove than what would occur under normal door closure forces.
    The seal contact check consists of applying chalk or other viable 
medium on the seal face and then closing and reopening the emergency 
escape air lock door. This will result in a pattern in the chalk (or 
other medium) that is representative of the door seal bead mating with 
the seal. If the chalk (or other medium) pattern does not show adequate 
contact, the seals are adjusted in the area of the gap. Following 
adjustment, the licensee performs a final seal contact check to verify 
the integrity of the sealing surface. The practice of verifying 
acceptable seal contact following performance of the overall air lock 
leak test and the acceptance criteria for this verification have been 
incorporated into the ANO, Unit 2, maintenance procedures.
    The performance of the 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 a request for 
additional information dated August 11, 2014 (ADAMS Accession No. 
ML14218A602), the NRC staff requested that the licensee provide test 
results to show the effectiveness of the seal contact check. In its 
supplement dated September 24, 2014, the licensee provided the test 
results following seal contact checks for refueling outages from 2008 
(2R19) to 2014 (2R23). In its supplement, the licensee stated that the 
results indicate that performance of the seal contact check is 
instrumental in the successful completion of subsequent leak testing. 
In its application, the licensee noted that acceptance criteria for 
containment building integrated leak rate testing (ILRT) has been met 
for each ILRT since initial plant startup, indicating that the 
emergency escape airlock door seals are meeting their design function 
when exposed to pressure in the correct (accident) direction.
    As an alternative to the between-the-seals pressure test of the 
emergency escape air lock required by Section III.B, Option B, Appendix 
J, 10 CFR part 50, the licensee has proposed a final door seal contact 
verification. This seal performance verification is completed following 
the full pressure airlock test, after the removal of the inner door 
strongback, and just prior to final closure of the airlock doors. The 
requested exemption would not affect compliance with the requirement to 
perform a full pressure emergency escape airlock test each refueling 
outage. Based on these results and information provided by the 
licensee, the NRC staff concludes that the containment building 
emergency airlock doors at ANO, Unit 2, function as designed using 
current methods of testing and maintenance, including seal contact 
checks. The NRC staff further concludes that the seal contact checks 
performed on the emergency escape airlock door seals ensure that the 
doors are sealing properly and will perform their design function to 
limit radiological release in the case of a postulated accident. 
Therefore, the NRC staff determined that the between-the-seals testing 
required by Section III.B, Option B, Appendix J, 10 CFR part 50, is not 
necessary to achieve the underlying purpose of the rule for the 
emergency escape air lock doors, given their current design. Since the 
above evaluations demonstrate that the underlying purpose of the rule 
will be met with the seal contact check, the NRC staff concludes that 
there is no undue risk to the public health and safety.

D. Consistent With the Common Defense and Security

    The licensee's exemption request is to utilize an alternative to 
the Type B containment emergency escape air lock door seal pressure 
testing requirement in Section III.B, Option B, Appendix J, 10 CFR part 
50. This exemption request is not related to, and does not impact any 
security issues at ANO, Unit 2. Therefore, the NRC staff determined 
that this exemption does not impact, and is consistent with, the common 
defense and security.

E. Environmental Considerations

    The NRC staff determined that the exemption discussed herein meets 
the eligibility criteria for the categorical exclusion set forth in 10 
CFR 51.22(c)(9) because it is related to a requirement concerning the 
installation or use of a facility component located within the 
restricted area, as defined in 10 CFR part 20, and issuance of this 
exemption involves no significant hazards consideration, no significant 
change in the types or a significant increase in the amounts of any 
effluents that may be released offsite, and no significant increase in 
individual or cumulative occupational radiation exposure. Therefore, in 
accordance with 10 CFR

[[Page 3263]]

51.22(b), no environmental impact statement or environmental assessment 
need be prepared in connection with the NRC's consideration of this 
exemption request. The basis for the NRC staff's determination is 
discussed as follows with an evaluation against each of the 
requirements in 10 CFR 51.22(c)(9)(i)-(iii).
Requirements in 10 CFR 51.22(c)(9)(i)
    The NRC staff evaluated whether the exemption involves no 
significant hazards consideration using the standards described in 10 
CFR 50.92(c), as presented below:
    1. Does the proposed exemption involve a significant increase in 
the probability or consequences of an accident previously evaluated?
    Response: No.
    The proposed change would permit emergency escape air lock door 
seal leak integrity testing to be performed by a seal contact check in 
place of the between-the-seals pressure test. The seal contact check 
will be performed following emergency escape air lock door opening, 
overall full pressure test of the emergency escape air lock, or air 
lock door seal contact adjustments. The seal contact test method will 
result in a continuation of the established practice at ANO, Unit 2, 
which has provided a high degree of confidence in door seal 
performance. The performance of the door seal contact test method at 
ANO, Unit 2, has led to the successful completion of subsequent 
emergency escape air lock full pressure tests since the procedural 
practice began. Furthermore, the acceptance criteria for containment 
building ILRT has been met for each ILRT since initial plant startup, 
indicating that the air lock door seals are meeting their design 
function when exposed to pressure in the correct (accident) direction. 
At Palisades Nuclear Plant, emergency escape air lock door seals which 
have been inspected in accordance with the proposed methodology have 
passed subsequent full pressure emergency escape air lock leakage tests 
and have not interfered with successful Containment Building ILRT.
    Since the proposed methodology can be used to successfully verify 
door seal condition and contact, the use of this methodology for 
testing will not cause an increase in the probability of a leaking 
emergency escape air lock door seal going undetected. The combination 
of the door seal contact check and the overall full pressure testing of 
the emergency escape air lock will provide high confidence of the air 
lock performing its design function under accident conditions.
    Therefore, this change does not involve a significant increase in 
the probability or consequences of an accident previously evaluated.
    2. Does the proposed exemption create the possibility of a new or 
different kind of accident from any accident previously evaluated?
    Response: No.
    The proposed change is associated exclusively with testing of 
features related to Containment Building integrity. The change affects 
only the testing methodology of the emergency escape air lock door 
seals. The proposed testing method does not result in any physical 
alterations to the plant configuration, no new structure, system, or 
component (SSC) is added, no SSC interfaces are modified, and no 
changes to any design function of an SSC or the methods of SSC 
operation are being made. As the proposed change would not change the 
design, configuration, or operation of the plant, the change would not 
cause the Containment Leakage Rate Testing Program to become an 
accident initiator.
    Therefore, this change does not create the possibility of a new or 
different kind of accident from an accident previously evaluated.
    3. Does the proposed exemption involve a significant reduction in a 
margin of safety?
    Response: No.
    The proposed change is associated exclusively with testing of 
features related to Containment Building integrity. The change affects 
only the testing methodology of the emergency escape air lock door 
seals. The change is unrelated to an initiator of any accident 
previously evaluated. The proposed application of a door seal contact 
check in lieu of a between-the-seals pressure test along with 
continuation of the overall full pressure test of the emergency escape 
air lock will continue to provide high confidence that the Containment 
Building leakage rate criteria for the emergency escape air lock will 
not exceed the maximum allowable leakage rates defined in the TSs or 
assumed in the accident analysis.
    Therefore, this change does not involve a significant reduction in 
a margin safety.
    Based on the above evaluation of the standards set forth in 10 CFR 
50.92(c), the NRC staff concludes that the proposed exemption involves 
no significant hazards consideration. Accordingly, the requirements of 
10 CFR 51.22(c)(9)(i) are met.
Requirements in 10 CFR 51.22(c)(9)(ii)
    The proposed exemption would allow containment emergency escape air 
lock door seal pressure testing to be performed by a seal contact 
verification test. This change only affects the leakage integrity 
testing methodology of the door seals, and does not change the 
frequency at which the testing must be performed. The proposed testing 
methodology serves the same purpose as the pressure testing required by 
regulations. Therefore, the proposed alternative testing methodology 
will not significantly change the types of effluents that may be 
released offsite, or significantly increase the amount of effluents 
that may be released offsite. Therefore, the requirements of 10 CFR 
51.22(c)(9)(ii) are met.
Requirements in 10 CFR 51.22(c)(9)(iii)
    The proposed exemption would allow containment emergency escape air 
lock door seal pressure testing to be performed by a seal contact 
verification test. This change only affects the leakage integrity 
testing methodology of the door seals and has no impact on, or change 
to, fuel or core design. Therefore, the proposed alternative testing 
methodology will not significantly increase individual occupational 
radiation exposure or significantly increase cumulative occupational 
radiation exposure. Therefore, the requirements of 10 CFR 
51.22(c)(9)(iii) are met.
Conclusion
    Based on the above, the NRC staff concludes that the proposed 
exemption meets the eligibility criteria for the categorical exclusion 
set forth in 10 CFR 51.22(c)(9). Therefore, in accordance with 10 CFR 
51.22(b), no environmental impact statement or environmental assessment 
need be prepared in connection with the NRC's issuance of this 
exemption.

IV. Conclusions

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), the 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. Also, special circumstances are present. 
Therefore, the Commission hereby grants the licensee an exemption from 
10 CFR part 50, Appendix J, Option B, Section III.B, Type B testing 
(seal pressure test) to perform a seal contact verification test, in 
lieu of seal pressure testing, for the ANO, Unit 2, emergency escape 
air lock doors.

[[Page 3264]]

    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 12th day of January 2015.

    For the Nuclear Regulatory Commission.
Michele G. Evans,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
[FR Doc. 2015-01032 Filed 1-21-15; 8:45 am]
BILLING CODE 7590-01-P