2CAN031402, ANO, Unit 2, LAR Supplemental Containement Building Emergency Escape Air Lock Testing and Exemption from Certain Requirements of 10 CFR 50, App J
| ML14077A139 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 03/17/2014 |
| From: | Jeremy G. Browning Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2CAN031402 | |
| Download: ML14077A139 (15) | |
Text
Entergy Operations, Inc.
1448 S.R. 333 Russellville, AR 72802 Tel 479-858-3110 Jeremy G. Browning Vice President - Operations Arkansas Nuclear One 2CAN031402 March 17, 2014 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
License Amendment Request Supplemental Containment Building Emergency Escape Air Lock Testing and Exemption from Certain Requirements of 10 CFR 50, Appendix J Arkansas Nuclear One, Unit 2 Docket No. 50-368 License No. NPF-6
REFERENCE:
Entergy letter dated January 21, 2014, License Amendment Request -
Containment Building Emergency Escape Air Lock Testing and Exemption from Certain Requirements of 10 CFR 50, Appendix J (2CAN011402, ML14021A085)
Dear Sir or Madam:
In accordance with the provisions of Title 10 of the Code of Federal Regulations (10 CFR)
Section 50.90, Entergy Operations, Inc. (Entergy) submitted a request for an amendment to the Arkansas Nuclear One, Unit 2 (ANO-2) Technical Specifications (TS) to revise the local leak test requirements for the Containment Building Emergency Escape Air Lock doors (Reference 1). The Reference 1 amendment request also included a request for exemption from certain requirements of 10 CFR 50, Appendix J, Primary Reactor Containment Leakage Testing for Water Cooled Power Reactors. Specifically, the exemption was requested under 10 CFR 50.12(a)(2)(iii) (undue hardship); however, 10 CFR 50.12(a)(2)(ii) (compliance not required to achieve underlying purpose of the rule) is equally applicable, consistent with an amendment approved previously by the NRC for the Palisades Nuclear Power station.
Based on the above, Entergy has revised Attachment 1 of the original (Reference 1) amendment request to include discussions related to 10 CFR 50.12(a)(2)(ii). In addition, an erroneous indirect reference to 10 CFR 50.12(a)(2)(v) is removed, since this criteria is unrelated to the ANO-2 exemption request.
Because the needed changes result in changes to page numbering and content, Attachment 1 of the Reference 1 amendment request is be replaced in its entirety. Therefore, Entergy requests the NRC replace Attachment 1 of the Reference 1 amendment request with that attached to this letter.
2CAN031402 Page 2 of 3 In accordance with 10 CFR 50.91(a)(1), Notice for public comment, the analysis about the issue of no significant hazards consideration (NSHC) using the standards in 10 CFR 50.92 is being provided to the Commission in accordance with the distribution requirements in 10 CFR 50.4.
In accordance with 10 CFR 50.91(b)(1), a copy of this letter and the reasoned analysis about NSHC is being provided to the designated Arkansas state official.
There are no additional commitments included in this letter.
If you have any questions or require additional information, please contact Stephenie Pyle at 479-858-4704.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on March 17, 2014.
Sincerely, ORIGINAL SIGNED BY JEREMY G. BROWNING JGB/dbb
Attachment:
Description and Assessment of the Proposed Changes
2CAN031402 Page 3 of 3 cc: Mr. Marc L. Dapas Regional Administrator U. S. Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 NRC Senior Resident Inspector Arkansas Nuclear One P. O. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Michael Orenak MS O-8G9A One White Flint North 11555 Rockville Pike Rockville, MD 20852 U. S. Nuclear Regulatory Commission Attn: Mr. Pete Bamford MS O-8B3 One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. Bernard R. Bevill Arkansas Department of Health Radiation Control Section 4815 West Markham Street Slot #30 Little Rock, AR 72205
Attachment to 2CAN031402 Description and Assessment of the Proposed Changes
Attachment to 2CAN031402 Page 2 of 12 DESCRIPTION AND ASSESSMENT OF THE PROPOSED CHANGES
1.0 DESCRIPTION
The proposed amendment would modify Technical Specifications (TS) associated with Arkansas Nuclear One, Unit 2 (ANO-2) Renewed Operating License NPF-6 to revise the local leak test requirements for the Containment Building Emergency Escape Air Lock doors. In accordance with 10 CFR 50.12, an exemption from certain requirements of 10 CFR 50, Appendix J, Primary Reactor Containment Leakage Testing for Water Cooled Power Reactors, is also requested for ANO-2.
The proposed amendment would modify TS 6.5.16 to require a seal contact verification in lieu of a seal pressure test with respect to the Emergency Escape Air Lock doors:
- b. Air lock acceptance criteria are:
- 1. Overall air lock leakage rate is 0.05 La when tested at Pa.
- 2. Leakage rate for each Personnel Air Lock door is 0.01 La when pressurized to 10 psig.
- 3. A seal contact check for each Emergency Escape Air Lock door, consisting of a verification of continuous contact between the seals and the sealing surfaces.
This amendment and exemption request is necessary due to the design characteristics of the ANO-2 Emergency Escape Air Lock doors. The door sealing capability relies, in part, on Containment Building pressure (the doors open into the Containment Building). In the absence of Containment Building pressure, a strongback must be installed to simulate this sealing force in order to perform testing between the two seals embedded in each door. Entergy has received substantial NRC inspection activity associated with testing of the ANO-2 Emergency Escape Air Lock doors, since the use of a strongback, although required from initial plant startup due to inherent design, can be considered a form of test pre-conditioning.
This amendment and exemption request is based most closely on that approved for Palisades on September 30, 1997 (Reference 1), and carried forward during the Palisades adoption of 10 CFR 50, Appendix J, Option B, approved on March 30, 2001 (Reference 2). Both ANO-2 and Palisades are Combustion Engineering plants with similar Containment Building Emergency Escape Hatch Air Lock door designs. provides markup pages of existing TS and TS Bases to show the proposed change. Attachment 3 provides revised (clean) TS pages. The TS Bases will be revised in accordance with the TS Bases Control Program (TS 6.5.14) upon implementation of this amendment, as committed to in Attachment 4 of this submittal.
Attachment to 2CAN031402 Page 3 of 12 2.0 ASSESSMENT 2.1 Description of Emergency Escape Airlock The air lock consists of a steel cylinder with circular doors at each end interlocked so that only one door can be open at any time. The air lock is designed to withstand all Containment Building conditions with either door or both doors closed. The doors open towards the interior of Containment Building and the door directly in contact with the Containment Building atmosphere is designated as the inner door. The air lock performs two functions: (1) capable of sealing and maintaining Containment Building integrity during accident conditions (verified by local leak rate testing (LLRT) and by Integrated Leak Rate Testing (ILRT)), and (2) capable of providing the Occupational Safety and Health Administration (OSHA) required emergency personnel egress from the Containment Building.
Double gaskets or seals are provided to seal each door. The seal material currently in use is an ethylene-propylene-diamine-monomer (EPDM), which is the vendor recommended material.
The air lock barrel may be pressurized to test its leak tightness without pressurizing the Containment Building. The Emergency Escape Air Lock doors each have two latching pins centered at the top and bottom of the door (corresponding to 12 o'clock and 6 o'clock positions).
The Emergency Escape Air Lock door latching pins serve only to position the door against the stationary bulkhead. The doors rely on the increase in containment pressure during a postulated event to provide sufficient closing force to produce an effective seal. The two latching pins alone do not provide an adequate circumferential closing force to allow meaningful door between-the-seals pressure testing.
Pressure testing without test clamps (strongback) is beyond the approved vendor technical manual instructions. The technical manual (TDT368X.0040) for the Emergency Escape Air Lock details the vendor instructions for leak testing the door seals:
In order to pressurize between the two seals on any door, the test clamp must first be bolted into place. This test clamp will simulate pressure sealing of the door and will also prevent the door from swinging open when the space between the two seals is pressurized.
WARNING: Do not pressurize the Airlock to full design pressure without first installing the test clamp on the door on the reactor end of the airlock. The door latch is not designed to take the full design pressure from the external direction. The test clamps should be securely in place before any pressure is put inside the airlock. The test clamp is designed to withstand the full design of the Airlock.
The door seals are required to be replaced every other refueling outage in accordance with the ANO Preventative Maintenance Program, but have been replaced each refueling outage during the recent past. The vendor Certificate of Compliance specifies the cure date (considered the manufacturing date) of each seal. The certificates provide a seal shelf life of 2 years from the cure date. The vendor (W.J. Woolley Company Nuclear, which was acquired by Trentec, now QualTech NP, in 1988) recommends a service life of approximately 5 years for each seal, beginning at the cure date.
Seal adjustment may be necessary following compression of the seal due to performance of the overall Emergency Escape Air Lock full pressure test or following installation and removal of a strongback. Such adjustment may include shimming or latch bracket adjustments. A review of inspections over the past 5 years has not identified a loss of seal resiliency.
Attachment to 2CAN031402 Page 4 of 12 2.2 Description of Present Surveillance Test During a design basis accident (DBA), the pressure applied forces the inner door against the seals. The outer door experiences DBA pressure only if the inner door seals leak by. During pressure testing of the overall air lock, a strongback (structural bracing) is necessary to simulate this pressure on the Containment Building side of the inner door and also to protect the inner door locking pins from the forces generated by the internal test pressure in the air lock barrel.
The use of a strongback to complete between-the-seals testing (either door) or full airlock pressure testing (inner door only) is required and was part of the original design of the doors.
This design does not permit unrestrained between-the-seals testing.
The between-the-seals test on a given air lock door is required after each door opening, except when the airlock is being used for multiple entries. The outer door must be opened following each overall test of the air lock to remove the strongback from the inner door. As discussed below, the inner door must also be opened to perform a seal contact check, since the seals may take a set when pressure applied by an overall air lock barrel test or a strongback is applied to the door.
Past TS surveillance testing for both the Emergency Escape Air Lock illustrates 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, the outer door must be opened to remove the strongback from the inner door, and 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. 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.
If the seal contact check reveals gaps, seal adjustment is performed to ensure that the seal maintains 360° of contact. Entergy Operations, Inc. (Entergy) considers seal adjustment a normal part of restoration from testing of the ANO-2 Emergency Escape Air Lock, which is controlled by procedure. The seal contact check consists of applying chalk or other viable medium on the seal face and then closing and reopening the 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, a final seal contact check is performed 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 maintenance procedures.
While the TS acceptance criteria for an air lock door is 0.01 La when pressurized to 10 psig, a conservative administrative leak rate limit of 1628 sccm is established at ANO-2. In response to NRC violation, procedures were revised in 2010 to require between-the-seals testing without the use of strongbacks. The first performance of the revised procedures occurred in the following refueling outage (February 2011). Both doors failed this leak test (11190 sccm and
Attachment to 2CAN031402 Page 5 of 12 52520 sccm, inner/outer door respectively). Subsequently, maintenance was performed with assistance from the vendor (new seals, new shims, lubrication, and adjusting the door latch brackets to increase the sealing forces), resulting in acceptable as-left test results. In the spring of 2012, ANO and vendor personnel developed a plan to improve maintenance and acquire detailed measurements during the next outage in the event future modification would be necessary. The as-found leak test of the outer door failed during the fall 2012 refueling outage (55145 sccm). Further modification and maintenance was performed (along with acquiring the aforementioned detailed measurements) and both doors passed their respective as-left leak tests.
3.0 TECHNICAL ANALYSIS
The TS changes are necessary due to the original design of the Emergency Escape Air Lock.
The annulus between the door seals cannot be successfully tested without the door strongback installed, as indicated by recent test data.
Entergy has performed additional low pressure between-the-seals testing on the Emergency Escape Air Lock door seals to measure seal leak rates at low initial pressures without the door strongbacks installed. The trial tests were performed at pressures near the 10 psig TS air lock test pressure requirement. With the annulus between the door seals pressurized to approximately 12 psig without the door strongback installed, the test pressure continued to dissipate rapidly. This indicates that the leak rates for between-the-seals testing on the Emergency Escape Air Lock cannot reasonably be properly evaluated against acceptance criteria when the door strongbacks are not installed. In summary, meaningful between-the-seals testing is not possible with the present design of the Emergency Escape Air Lock doors, without the installation of strongbacks or without significant closing torque being applied to the door closure mechanisms. 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 on the inner door.
The pressure applied during a between-the-seals test is in the opposite direction of accident pressure and will act to lift the door open or off its seating surface. Accident pressures apply forces to the door in the designed direction for greater seal contact and leak tightness. The dual-seal design of the door is such that the direction of air pressure during an accident requires that both seals fail to seal for leakage to pass through door. This is in contrast to a pressure test between the door seals, which acts to lift the door open and will only verify that one of the two seals is not seated. In other words, the failure of a low pressure seal test does not prove the door would not seal in an accident scenario. In addition, to create a door seal-related direct leakage path to the outside atmosphere, both seals on both doors must fail. Note that ANO-2 has performed six ILRTs following initial startup, all of which passed acceptance criteria, indicating the Emergency Escape Air Lock doors are meeting the Containment Building design function when exposed to pressure in the correct (accident) direction.
As a result of NRC violations that are largely based on the use of a strongback as test pre-conditioning, Entergy has responded with significant effort to perform door testing without the use of a strongback. Efforts included significant maintenance, with onsite vendor support, performed over recent years and a significant increase in the torque applied to the door during closure. At least one instance of an employee becoming trapped inside the air lock has occurred due to the excessive force now necessary to operate the opening/closing mechanism.
Although a torque amplifying device has been stationed to assist personnel in door operation, this excessive torque is contrary to the industrial safety purpose of the air lock in providing an immediate escape route from the Containment Building.
Attachment to 2CAN031402 Page 6 of 12 As an alternative to the final between-the-seals pressure test required by the TS for verification of door seal functionality, Entergy proposes 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 TS changes would not affect compliance with the present requirement to perform a full pressure Emergency Escape Air Lock each refueling outage. The seal contact check replaces the pressure test required by the Containment Leakage Rate Testing Program for the door opening(s).
Based on the described circumstances and the above evaluation, Entergys proposal to perform seal contact testing in lieu of between-the-seals leak rate testing on the Emergency Escape Air Lock door seals is acceptable.
4.0 EXEMPTION REQUEST Entergy Operations, Inc. (Entergy) is the holder of Facility Operating License No. NPF-6, which authorizes operation of the Arkansas Nuclear One, Unit 2 (ANO-2) plant. The ANO-2 facility is a pressurized-water reactor located in Pope County, Arkansas.
In accordance with 10 CFR 50.12, an exemption from certain requirements of 10 CFR 50, Appendix J, Primary Reactor Containment Leakage Testing for Water Cooled Power Reactors, is requested for ANO-2. The proposed amendment would modify TS 6.5.16 to require a seal contact verification in lieu of a seal pressure test with respect to the Emergency Escape Air Lock doors.
10 CFR 50, Appendix J, Option B, III.B requires, in part, Type B pneumatic tests to detect and measure local leakage rates across pressure retaining, leakage-limiting boundaries The aforementioned exemption is necessary due to the original design of the Emergency Escape Air Lock. Over recent years, a between-the-seals pressure (pneumatic) test of the Emergency Escape Air Lock doors has routinely failed without the use of a strongback to simulate Containment Building accident pressure. On rare occasions, minor modifications accompanied with significant maintenance efforts have resulted in successful performance of the as-left between-the-seals test; however, the following as-found tests grossly failed, even at low test pressures of approximately 12 psig. The vendor has clearly stated the ANO-2 design does not support testing absent use of a strongback and, to meet leak rate limits, the airlocks 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.
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. In 2008, after an individual became trapped in the air lock due to being unable to open the door, a torque amplifying device has been installed to assist personnel in door opening/closing. During the fall outage in 2012, the outer door required mechanical agitation to open and it was noted that the 3/4 stainless steel latch pins were bent.
Based on efforts to date, Entergy has concluded that attempting to apply excessive closing torque to the door necessary to overcome the original design characteristics is inappropriate.
Based on historical information, the failed attempts to consistently perform the subject test without the use of a strongback, and the industrial safety aspects associated with modifying the door closing torque, Entergy requests an exemption to utilize a seal contact check in lieu of the between-the-seals pressure test.
Attachment to 2CAN031402 Page 7 of 12 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 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, provided special circumstances are present.
Authorized by Law This exemption would allow a seal contact check to be performed on the ANO-2 Emergency Escape Air Lock doors in lieu of a between-the-seals test. The seal contact check ensures that the door seals are in full contact with the door face and will provide high confidence that no leak path has been created past the seals due to ingress/egress through the air lock. In addition, the air lock barrel pressure test will continue to be performed as required by the TSs, which verifies the overall leak integrity of the air lock. Finally the door seals will continue to be part of the test boundary during the Containment Building integrated leak rate test (ILRT). This request is similar to that approved for the Palisades plant in September 1997 (Reference 1). As stated above, 10 CFR 50.12 allows the NRC to grant exemptions from the requirements of 10 CFR Part 50. The NRC staff has previously concluded that granting a similar request for another licensee does not result in a violation of the Atomic Energy Act of 1954, as amended, or the Commissions regulation. The exemption will continue to ensure the safety function of the air lock to minimize or prevent radioactive leakage from the Containment Building during postulated events and will provide Entergy the opportunity to utilize the door as originally designed, which supports the industrial safety function of permitting relatively rapid, easy egress for the Containment Building during emergency conditions. Based on the above, the exemption is authorized by law.
No Undue Risk to Public Health and Safety The test methods are intended to verify the design function capability of the ANO-2 Emergency Escape Air Lock to provide adequate protection for public health and safety. Emergency Escape Air Lock remains fully capable of performing the required design function during normal and accident operational conditions. The Emergency Escape Air Lock doors maintain a successful history in meeting the periodic full pressure test requirement of the air lock and Containment Building ILRTs. The door seal contact check, in conjunction with the full pressure air lock test, has been shown to be effective in maintaining the design function of the air lock, recently at ANO-2 and for many years at the Palisades plant (Reference 1), which has a similar Emergency Escape Air Lock door design. In addition, the currently required between-the-seals pressure test on the door seals acts to lift the door from the sealing surface and only proves that one of the two seals is leaking. Failure of all four seals (two per door) would need to occur before the design function of the air lock to limit the release of radioactivity from the Containment Building during postulated events would become degraded. Based on the above, no new accident precursors are created by replacing the between-the-seals pressure test with a seal contact check. In addition, the probability of postulated accident and the potential consequences of an accident are not increased. Therefore, the proposed exemption will not result in undue risk to public health and safety.
Consistent with Common Defense and Security The proposed exemption has no relation to security issues. The common defense and security is, therefore, not impacted by this exemption.
Attachment to 2CAN031402 Page 8 of 12 Special Circumstances 10 CFR 50.12(a)(2)(ii)
Application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule Entergy has performed low pressure between-the-seals testing on the Emergency Escape Air Lock door seals to measure seal leak rates at low initial pressures without the door strongbacks installed. The trial tests were performed at pressures near the 10 psig TS air lock test pressure requirement. With the annulus between the door seals pressurized to approximately 12 psig without the door strongback installed, the test pressure continued to dissipate rapidly.
This indicates that the leak rates for between-the-seals testing on the Emergency Escape Air Lock cannot reasonably be properly evaluated against acceptance criteria when the door strongbacks are not installed. In summary, meaningful between-the-seals testing is not possible with the present design of the Emergency Escape Air Lock doors, without the installation of strongbacks or without significant closing torque being applied to the door closure mechanisms.
Entergy considers seal adjustment a normal part of restoration from testing of the Emergency Escape Air Lock. If the seal contact check reveals gaps, seal adjustment is performed to ensure that the seal maintains 360° of contact. The seal contact check consists of applying chalk or other viable medium on the seal face and then closing and reopening the 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, a final seal contact check is performed 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 maintenance procedures.
The underlying purpose of between-the-seals testing is to verify the seal integrity after an Emergency Escape Air Lock door is opened. The seal contact check and, if necessary, adjustment performed on the door seal serve this purpose and ensure the door is sealing properly. Therefore, the application of the regulation to perform between-the-seals pressure testing following full pressure test of the Emergency Escape Air Lock is unnecessary to achieve the underlying purpose of the rule.
Compliance would result in undue hardship or other costs that are significantly in excess of those contemplated when the regulation was adopted, or that are significantly in excess of those incurred by others similarly situated Special circumstances, in accordance with 10 CFR 50.12(a)(2)(iii), are present whenever compliance would result in undue hardship or other costs that are significantly in excess of those contemplated when the regulation was adopted, or that are significantly in excess of those incurred by others similarly situated. The current required testing does not account for original air lock door designs that do not reasonably permit successful testing without use of external pressure being applied (via a strongback in this case). ANO-2 has received violations related to
Attachment to 2CAN031402 Page 9 of 12 the use of a strongback during air lock door testing as potential test pre-conditioning. As a result, significant maintenance, with onsite vendor support, was attempted to replace many door components and increase the closing torque of the doors. While these efforts resulted in some successful testing of the door seals, the secondary function of the air lock to meet OSHA industrial safety requirements (i.e., provide a relatively easy-to-operate escape path from the Containment Building during emergency conditions) has been significantly degraded.
In light of the above, Entergy, with vendor support, has investigated the potential of substantial modifications to the air lock doors in order to meet the current seal pressure test requirements and the OSHA requirements. Beyond the many components previously replaced along with spring upgrades to help alleviate the excessive force now needed to operate the doors, Entergy has determined complete door replacement (retrofit) would be necessary to resolve the aforementioned issues. Vendor proposals have been received and the associated Entergy cost study has been completed, resulting in an estimated total of over $3,000,000. While high confidence exists that such a modification would resolve the issues at hand, there are not guarantees that all issues will be completely eliminated. The cost of pursuing such a modification is unwarranted because no appreciable increase in nuclear or public safety would be realized. Based on the estimated costs of modifications and because both the radiological and industrial safety aspects associated with the Emergency Escape Air Lock will continue to be met under the proposed exemption, special circumstances have been shown to exist, in accordance with 10 CFR 50.12(a)(2).
As demonstrated above, the requested exemption is authorized by law, does 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. Based on this, Entergy believes the requested exemption should be granted for ANO-2.
5.0 REGULATORY ANALYSIS
5.1 No Significant Hazards Consideration Determination Entergy Operations, Inc. (Entergy) has evaluated the proposed changes to the TS using the criteria in 10 CFR 50.92 and has determined that the proposed changes do not involve a significant hazards consideration.
Entergy proposes a change to the Arkansas Nuclear One, Unit 2 (ANO-2) Technical Specifications (TSs), that would permit a seal contact check in lieu of between-the-seal pressure testing associated with the Containment Building Emergency Escape Air Lock door seals.
Overall full pressure testing of the Emergency Escape Air Lock will continue at required frequencies. The proposed change also requires an exemption from 10 CFR 50, Appendix J, Primary Reactor Containment Leakage Testing for Water Cooled Power Reactors, Option B, leak rate testing requirements.
Basis for no significant hazards consideration determination: As required by 10 CFR 50.91(a),
Entergy analysis of the issue of no significant hazards consideration is presented below:
Attachment to 2CAN031402 Page 10 of 12
- 1. Does the proposed change 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 rate testing to be performed by a seal contact check following door opening, overall full pressure test of the Emergency Escape Air Lock, or seal contact adjustments. The seal contact test method will result in a continuation of the established practice which has provided a high degree of confidence in door seal performance. At Palisades 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 Integrated Leak Rate Testing (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 change 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 change 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
Attachment to 2CAN031402 Page 11 of 12 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 of safety.
Based upon the reasoning presented above, Entergy concludes that the requested change involves no significant hazards consideration, as set forth in 10 CFR 50.92(c), Issuance of Amendment.
5.2 Applicable Regulatory Requirements/Criteria ANO-2 TS 6.5.16 establishes the program required to implement the leakage rate testing of the Containment Building as required by 10 CFR 50.54(o) and 10 CFR 50, Appendix J, Option B, as modified by approved exemptions. This program is required to be in accordance with the guidelines contained in NEI 94-01, Revision 2-A, Industry Guideline for Implementing Performance-Based Option of 10 CFR Part 50, Appendix J, dated October 2008.
ANSI/ANS-56.8-2002, "Containment System Leakage Testing Requirements describes the inspection and testing requirements necessary to fulfill the intent of the requirements of NEI 94-01, Revision 2-A, as specified in the TS. Because the integrity of the primary containment boundary with respect to leakage will continue to be verified as required by the above, with approved exemptions, no change in the primary containment boundary's ability to fulfill its design function is introduced.
5.3 Precedence This amendment and exemption request is based most closely on that approved for Palisades on September 30, 1997 (Reference 1), and carried forward during the Palisades adoption of 10 CFR 50, Appendix J, Option B, approved on March 30, 2001 (Reference 2). Both ANO-2 and Palisades are Combustion Engineering plants with similar Containment Building Escape Hatch Air Lock door designs.
6.0 ENVIRONMENTAL CONSIDERATION
The proposed change would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR Part 20, and would change an inspection or surveillance requirement. However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed change.
Attachment to 2CAN031402 Page 12 of 12
7.0 REFERENCES
- 1. NRC letter to Palisades dated September 30, 1997, Palisades Plant - Issuance of Amendment Re: Containment Emergency Escape Air Lock Testing, and Exemption from Certain Requirements of 10 CFR Part 50, Appendix J (TAC No M94528) (ML020840256)
- 2. NRC letter to Palisades dated March 30, 2001, Palisades Plant - Issuance of Amendment Re: Option B Containment Leak Rate Testing (TAC No: MB0855) (ML010930230)