U-603061, Requests Temporary Schedular Exemption from Requirements of 10CFR50,App J,To Defer LLRT of Primary Containment Penetration 1MC-042 at CPS Until Startup from Next Scheduled Refueling outage,(RF-7)

Requests Temporary Schedular Exemption from Requirements of 10CFR50,App J,To Defer LLRT of Primary Containment Penetration 1MC-042 at CPS Until Startup from Next Scheduled Refueling outage,(RF-7)

ML20237B941
Person / Time
Site:	Clinton
Issue date:	08/13/1998
From:	Walter MacFarland ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
U-603061, NUDOCS 9808200109
Download: ML20237B941 (12)

Text

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tilinois Power Company Chnton Power Station P.O Box 678 Chnten, IL 61727 Tel 217 935-5623 Fax 217 935-4632 Walter G. MacFarland IV 4

Senior Vice President and Chief Nuclear Officer ILLIN#IS uomi P6WER se.iooc An illinova Company August 13, 1998 Docket No. 50-461 10CFR50.12 Document Control Desk Nuclear Regulatory Commission ,

Washington, D.C. 20555

Subject:

Clinton Power Station Application for a Temporary Schedular Exemption from 10CFR50 Appendix J Regarding Local Leakage Rate Test for Primary Containment Penetration IMC-042

Dear Madam or Sir:

Pursuant to 10CFR50.12, Illinois Power (IP) hereby requests a temporary schedular exemption from the requirements of 10CFR50, Appendix J, to defer the local leakage rate test (LLRT) of primary containment penetration IMC-042 at Clinton Power Station (CPS) until startup from the next scheduled refueling outage (RF-7).

The last LLRT for IMC-042 was performed early during the current outage period at CPS. Due to the length of the ongoing extended outage, the test interval (30 /

/

months) for IMC-042 will expire prior to the next scheduled refueling outage. For reasons more fully explained within Attachment 2 to this letter, including consideration of the consistently acceptable leakage performance of this penetration in the past, and yet, the significant evolution required to test this penetration at this time, IP has determined that re-testing this penetration prior to plani restart from the is impractical and unnecessarily burdensome relative to any safety benefit to be gained by reperforming the LLRT, Consistent with this determination, IP believes this request meets the criteria of 10CFR50.12 for the NRC to grant a temporary, specific exemption.

Attachment 3 to this letter contains an environmental impact statement assessing the criteria identified in 10CFR50.12. Furthermore, an affidavit supporting the facts set forth in this letter and its attachments is provided as Attachment 1.

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U-603061 Page 2 s .,

Please note that the planning of remaining work activities for the current shutdown period is significantly dependent on the NRC's approval of the subject temporary exemption. IP therefore respectfully requests NRC's prompt review and determination I regarding approval of this exemption request in anticipation of plant startup in the fourth quarter of this year. l i

Sincerely yours,

3 Walter G. MacFarland, IV Senior Vice President and ChiefNuclear Officer JFK/krk Attachment

'l cc: Acting Regional Administrator, Region III, USNRC NRC Clinton Licensing Project Manager NRC Resident Office, V-690 1 Illinois Department of Nuclear Safety l 1

Attachment I to U-603061 Page1ofI  ;

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• Walter G. MacFarland, IV, being first duly sworn, deposes and says: That he is Senior Vice President and Chief Nuclear Officer for Clinton Power Station; that this application for a temporary schedular exemption of Facility Operating License NPF-62 has been prepared under his supervision and direction; that he knows the contents thereof; and that j to the best of his knowledge and belief said letter and the facts contained therein are true and correct.

1 i

Date: This I day of August 1998.

h Signed: .

f Walter G. MacFarland, IV STATE OF ILLINOIS ( SS.

(

hOk COUNTY (

Subscribed and sworn to before me this I day of August 1998.

r _ _ _ _- - : .

3 ll

• OFFICIAL SEAL

• h M

h Joseph V. Sipok

' {

j Notary Public, State of IM  ;

s My Commission Empires 11/24/2001 q i(Nota p blic) l j

T:::_ _ _ _ _ : _::::-::-

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Attachment 2 to U-603061 Page 1 of 6 BaclIground Primary containment penetration IMC-042 is provided for the reactor pressure vessel l

(RPV) head spray piping associated with the reactor core isolation cooling (RCIC) and '

residual heat removal (RHR) systems. The head spray piping contains flanged connections to permit disassembly and removal of this piping to allow the RPV head to be removed for  ;

refueling operations.

The local leakage rate test (LLRT) for primary containment penetration IMC-042 (see attached figure) is normally performed during a refueling outage when the drywell head and the RPV head spray piping are removed. A blind flange is installed at the drywell bulkhead to establish a boundary for performing the LLRT of penetration IMC-042. The test volume extends from the blind flange installed at the drywell bulkhead, through the ,

connecting ASME Class I piping, to the outboard primary containment isolation valves. J Compliance with 10 CFR Part 50, Appendix J, provides assurance that the primary 4

containment, including those systems and components which penetrate the primary containment, do not exceed the allowable leakage rate specified in the Technical Specifications (TS). The allowable leakage rate is determined so that the leakage assumed in the safety analyses is not exceeded.

On September 12,1995, the NRC approved issuance of a revision to 10CFR50, Appendix l J, which became effective on October 26,1995. This revision added Option B

" Performance-Based Requirements" to Appendix J to allow licensees to voluntarily replace the prescriptive testing requirements of Appendix J with testing requirements based on both overall and individual component leakage rate performance. Regulatory Guide 1.163, was developed as a method acceptable to the NRC staff for implementing Option B. This regulatory guide states that the Nuclear Energy Institute (NEI) guidance document NEI 94-01, " Industry Guideline for Implementing Performance-based Option of 10 CFR Part 50, Appendix J" provides methods acceptable to the NRC staff for complying with Option B (with certain exceptions described therein). Option B was approved for use at CPS by Amendment 105 to the facility operating license and implemented during the sixth refueling outage.

Per the guidance given in NEI 94-01, for a licensee to determine the performance of each component included in the primary containment leakage rate testing program, criteria that are indicative of performance, such as an administrative leakage limit, must be established.

The administrative limit is selected to be indicative of the potential onset of component degradation. Failure to meet an administrative limit requires the test interval for the associated component / penetration to be returned to the minimum interval.

Under the Appendix J, Option B program guidelines, as given by NEI 94-01, " extensions in Type B and Type C test intervals are allowed based upon completion of two consecutive periodic As-found tests where the results of each test are within a licensee's )

allowable administrative limits." Under the CPS program, the minimum test interval for a j containment penetration is 30 months. Therefore, for successful completion of two i i

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Attachment 2 to U-603061 Page 2 of 6 consecutive as-found tests, a 60-month interval may be used. Per the guidance ofIP's internal procedure governing the Primary Containment Leakage Rate Testing Program at CPS, an as-found test is required prior to any repair, modification, or adjustment activity which could affect a component's leakage rate. Also, Appendix E," Testing Requirement Positions," of this same procedure states specifically that torque switch adjustment or j spring pack replacement (i.e., certain activities associated with motor-operated valve j maintenance) require as-found and as-left leakage rate testing of the affected valve. i For initiating the Option B program at CPS, the leakage performance (leak rate test history) of each containment penetration at CPS was evaluated to establish an initial testing frequency for each penetration within the Primary Containment Leakage Rate Testing Program. At the inception of this program at CPS, the subject penetration, IMC- ,

042, was assigned an initial base test interval of 30 months because an as-found test was '

not performed for this penetration in the fifth refueling outage, prior to performing some motor-operator testing and adjustment for one of the isolation valves (IE12-F023) associated with penetration IMC-042. Prior to the adoption of Option B there was no requirement to perform as-found testing for maintenance activities of this type.

Earlier during the current outage, an LLRT for this penetration was completed on December 8,1996. The same penetration, which included leakage through 1E12-F023, demonstrated satisfactory as-found leakage results. However, per the guidelines of NEI 94-01, one additional satisfactory as-found test is required before the penetration can be placed on an extended 60-month test interval.

Problem Description Clinton Power Station (CPS) has been in an extended shutdown period since before the last performance of the LLRT for IMC-042. Since this penetration is on a 30-month test interval (such that the next LLRT is due again on June 8,1999), and since plant conditions at this point in the current outage are not conducive for re-performing the LLRT prior to plant startup, a special mid-cycle shutdown would be necessaiy without the requested temporary exemption to defer performance of the next LLRT until startup from the next ,

scheduled refueling outage (RF-7). l l

Historic Leakage Performance '

[ Historically, the LLRTs for penetration IMC-042 have yielded excellent leakage results. )

This penetration is tested by CPS surveillance procedure 9861.02D016, test set A. The l I

test challenges four containment isolation valves in a group, and the leakage result is the total leakage of all four valves. The tested valves are 1E12-F061, IE12-F023, IE51-F013,1E51-F391 (see attached diagram). The administrative limit for this group of valves is 20,000 secm.

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Attachment 2 to U-603061 Page 3 of 6 I

For the last three outages the leakage history of penetration IMC-042 is as follows:

RF-4 This penetration was given a pretest prior to Generic Letter (GL) 89-10 static testing on motor-operated valve (MOV) 1E51-F013, per maintenance work request (MWR) D35177. As-found leakage was 20 seem and as-leR leakage was l 10 sccm.

i l' RF-5 GL 89-10 static testing was performed on MOV IE12-F023, per MWR D56864.

The spring pack and torque switch were removed, the spring pack was tested and adjusted, and the thrust was measured using motor-operated valve diagnostic equipment. No as-found test was performed since the orogram did not require it at the time. The as-len leakage for penetration IMC-042 was 20 secm.

! The MWR D56864 Summary states: "the as-found condition of the valve was l normal, with no abnormalities noted." The torque switch and spring pack were removed and the spring pack was tested and adjusted per CPS 8451.11, "Use of Spring Pack Tester." Per the requirements of CPS 8451.11, any visual signs of damage or required maintenance shall be documented on Checklist 8451.11C001.

Based on a review of the GL 89-10 MOV notebook for IE12-F023, no evidence suggests that any faulty condition was observed or documented. The spring pack

, was adjusted and reinstalled along with the torque switch As-leR VOTES testing I was performed to show that the valve thrust was within acceptable limits. The as-lea LLRT measured 20 seem for the penetration.

RF-6 IE51-F013 was modified by drilling a hole in the disc to address Generic Letter -

l 93-07 concerns. As-found leakage for penetration IMC-042 was 179 sccm, and i as-leR leakage was 100 secm, or 0.5% of the administrative limit.

Testina Approaches Several optional approaches for completion of the LLRT for penetration IMC-042 were considered in lieu of requesting a temporary exemption to delay the LLRT until startup from the next scheduled refueling outage (RF-7).

l 1.) Testing in the normal manner l Testing in the normal manner requires disassembly of the head spray piping. Disassembly of the head spray piping to allow installation of the blind flange requires draining the reactor cavity' pool and removal of the drywell head for access. This represents a considerable burden in dose and work scope. Dose records at CPS show that approximately 1.875 Rem of occupational exposure is received when draining and decontaminating the reactor cavity pool, removing of the drywell head, and disassembling the associated piping. Little, if any, additional assurance ofleakage integrity will be gained by re-testing the subject penetration because this system has had little use since it was last tested, the as-len leakage was extremely low when tested earlier in this shutdown 1

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Attachment 2 to U-603061 i Page 4 of 6 period (RF-6), and there have been no mechanisms identified that could have changed the leakage characteristics of the penetration.

Also, significant post-maintenance testing would be required following reassembly of the drywell head and associated piping, including a system leakage test and VT-2 inspection of the applicable Class 1 piping at operating pressure.

2.) Applying a freeze seal

, Although it is possible to apply a freeze seal to this line to form one of the LLRT test . l I

boundaries, the inherent difficulties and disadvantages associated with this option render this option undesirable. A freeze seal will cool the piping below the brittle transition

! temperature of the material (approximately minus 40 degrees Fahrenheit for carbon steel). ,

As a result, a detailed piping analysis and extensive compensatory measures would be required. For example, it would be necessary to design and install temporary piping l supports to ensure that the piping is completely immobilized during the freeze sealing process to prevent undesirable movement that may result in unacceptable stress levels being generated in the piping. Furthermore, industry experience has shown that a freeze seal does not make an ideal air test boundary. The ice can become sufficiently porous such that enough air could seep through the seal to indicate a failed test. Also, the air leaking through the freeze seal can weaken the seal thus rendering it even less likely to

perform its intended isolation function. Therefore, creating a test volume boundary by use l of a freeze sealis not desirable.

3.) Flooding the reactor vessel An alternative to removing the head spray piping is to raise RPV water level to above the main steam lines and include the upper portion of the vessel and several additional boundary valves in the test volume. Specifically, the reactor head vent valves, IB21-F001 and IB21-F002, maintenance valve IB21-F005, and RPV water level transmitter root valve IB21-F453 would be used to bound the test volume on the vessel side. This approach is undesirable for the following reasons. First, the majority of the test volume would be beyond the true test boundary, and any leakage from the additional boundary valves would penalize the penetration by not providing a true measure of the containment

leakage. Secondly, system preparation and lineup for this test would constitute a

l. significant permutation of the plant schedule and normal course of operations. The i additional risk associated with such a complex evolution is not justified by a commensurate gain in safety resulting from a successful completion of the test.

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Attachment 2 to U-603061 i Page 5 of 6 4.) Install a blind flange with the piping in place Because of the space restrictions beneath the drywell head, any attempt to rig the piping to allow a test flange to be installed would be extremely difficult and would include significant personnel safety concerns. Any attempt at this type of disassembly will result in an accumulation of additional dose, and upon reassembly, a system leakage test and VT-2 examination would be required, leading to more dose expenditure and schedule ,

permutation. The gain in assurance ofleakage integrity does not offset the burden and  !

commensurate risk of the activity.

Conclusion Penetration IMC-042 has an excellent LLRT history and has not been exposed to operating conditions since last tested. There have been no challenges to the system or operational events that could have caused a degradation in leakage performance of the subject penetration. Re-performance of the test by a method designed to preclude disassembly of the drywell head and disconnection of the associated RPV head spray ,

piping (such as would occur during a refueling outage) introduces an unacceptable degree i of additional risk to the plant. It requires a significant expenditure of manpower and dose, necessitates complex and costly post-maintenance testing, and is thus unnecessarily burdensome with no resulting increase in assurance of safety.

Because an as-found LLRT was not performed in RF-5 prior to motor-operator static testing (GL 89-10) of a particular associated containment isolation valve, an LLRT test interval of 30 months had to be established for penetration 1MC-042, as opposed to an extended 60-month interval. The acceptable condition of that specific valve, as well as the other isolation valves for this penetration, was subsequently demonstrated by successful LLRTs during RF-5 and earlier during the current outage. This penetration has not been exposed to any significant degradation mechanisms since it was last tested.

Based on the above, re-performing the LLRT on 1MC-042 at any time prior to the next scheduled refueling outage (RF-7) is neither a conservative decision nor in the best interest of safe operation of the plant or ALARA Further, any alternate testing methods, such as allowing the penetration to be tested with the head spray piping in place, will introduce a level of risk which will outweigh any gain in assurance ofleakage integrity or increase in the confidence of the ability of the system to perform its safety function.

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Attachment 3 to U-603061 1 Page 1 of 3 Environmental Assessment l

Backaround IP's request is based on granting a temporary schedular exemption from the 10CFR50,

. Appendix J, Option B, local leakage rate testing (LLRT) requirements to defer testing of primary containment penetration IMC-042 until the next scheduled refueling outage.

Licensing of Clinton Power Station (CPS) was based, in part, on the NRC's evaluation of the CPS design as it conforms to the requirements of 10CFR50, Appendix J. The NRC's review, evaluation and acceptance of the Appendix J testing program, as described in the CPS Final Safety Analysis Report, was documented in the CPS Safety Evaluation Report (NUREG 0853) issued to support licensing of the facility. IP's request to temporarily defer the LLRT of IMC-042 does not specifically meet the testing interval as defined in . ]

Option B. Specifically, before a primary containment penetration can be placed on an extended (60-month) interval, two consecutive successful as-found tests are required.

- During the fifth refueling outage some motor-operated valve maintenance was performed on one of the isolation valves for IMC-042 without performing an as-found test since an _

as-found test for that type of maintenance was not required at that time (prior to CPS adopting Appendix J, Option B) since it was a non-ILRT outage. Due to the extended outage occurring at CPS, the 30-month LLRT interval for IMC-042 will expire prior to the next scheduled refueling outage. Consequently, a temporary schedular exemption from the testing interval requirements of 10CFR50, Appendix J, Option B for primary containment penetration IMC-042 to defer the next LLRT until the next scheduled refueling outage is required.

The Need for the Proposed Temporary Exemption The proposed action is needed to defer the next LLRT of the r.ibject penetration until the l next scheduled refueling outage.

Strict conformance to the LLRT interval requirements of Appendix J, Option B requires 1

- that primary containment penetration IMC-042 be placed on a 30-month testing interval.  !

One of the requirements to place this penetration on an extended (60-month) interval is to  !

successfully pass two consecutive as-found LLRTs. IMC-042 does not strictly meet this  ;

criterion since no as-found testing was performed during the fifth refueling outage. As- ,

t found testing was not performed because, at the time, it was not required for the type of maintenance performed on one of the isolation valves for the subject penetration.

j IMC-042 has always demonstrated excellent leakage performance. Based on the L . performance history of IMC-042, the low overall primary containment leakage rate, and E, the large margin to the allowable leakage, IP does not expect the temporary extension of

the LLRT test interval to be accompanied by any significant increase in leakage through

[ the penetration. Additionally, leakage through this penetration would be into the l- downstream piping (RHR), which is completely contained within the secondary

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Attechment 3 to U-603061 Page 2 0f 3

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containment boundary envelope. On this basis, the proposed exemption involves no significant impact on the total containment atmosphere leakage assumed in the accident analyses.

Due to the current plant status, the proximity of startup from the current outage, the number and types of remaining activities that must be performed in preparation for plant startup, the lack of any feasible alternative testing method, the scope of work necessary to perform the normal method of teriing the subject penetration (which includes significant manipulations of major pieces of plant equipment), the absence of any identified aggressive degradation mechanism since the last successful LLRT was completed, and the minimal added assurance ofleakage integrity for the subject penetration that would be gained by re-performing the LLRT at this time, IP has determined that it is impractical and unnecessarily burdensome to re-perform the LLRT of IMC-042 before the next scheduled refueling outage.

Based on the above, the strict application of the testing requirements of 10CFR50, Appendix J - Option B, for CPS primary containment penetration IMC-042 is not necessary to achieve the underlying purpose of the rule, and would impose undue hardships to IP.

Radiolo2ical Environmental Assessment The change will not increase the probability or consequences of accidents or normal effluents. No changes are being made in the types of any effluents that may be released offsite, and there is no significant increase in the allowable individual or cumulative occupational radiation exposure. Accordingly, IP concludes that there are no significant radiological environmental impacts associated with the proposed temporary exemption.

Non-Radiological Environmental Assessment IP has concluded that, apart from the parameters mentioned above, the operating parameters evaluated with regard to the potential impact of Clinton Power Station operation on the environment, will be unaffected or remain bounded by the original values considered or identified in the Final Environmental Statement.

With regard to potential non-radiological impacts, the proposed action involves features located entirely within the restricted area as defined in 10CFR20. It does not affect non-radiological plant effluents and has no other environmental impact. For example, IP has concluded that the only feasible alternative to the requested temporary schedular 1 l exemption is to proceed with testing the subject containment penetration in the normal I method. Testing this penetration now (or at any time prior to the next scheduled refueling i outage) would require the use of extra resources due to the extent of plant dist.ssembly (e.g., draining the upper pool, remov'.ng the drywell head, disassembling the reactor vessel l head spray piping, etc.) required to gain access to the subject containment penetration. 1

. Performing the LLRT during a refueling outage is the most efficient method since the l plant components that are currently interfering with completing the LLRT are removed as

Att:chment 3 1o U-603061 Page 3 of 3 a result of the preparations necessary to conduct refueling operations. Accordingly, IP concludes that there are no significant non-radiological impacts associated with the proposed temporary exemption.

Alternatives to the Proposed Temporary Exemotion Since IP has concluded there is no measurable environmental impact associated with the proposed action, any alternatives with equal or more favorable environmental impact need not be evaluated. The only principle alternative would be to deny the requested exemption. Denial of the application would result in no change in current environmental impacts and would reduce operational flexibility of the facility. This reduction in operational flexibility would be manifested in one of two ways. The first would be to delay the planned startup of the facility in order that the subject testing could be performed at this time. The second option would be to continue plant startup as currently scheduled and resume normal operations until the testing interval for the penetration is nearly expired, at which time the plant would be shut down to perform the testing.

Given that the proposed temporary exemption supports the ALARA init iative, without a significant increase in risk to the public due to deferring the LLRT of IMC-042 until the next scheduled refueling outage, there are no significant environmental effects associated with the proposed temporary exemption beyond those attributed to normal operation of the facility. Other alternatives would have no greater, favorable environmental impact.

Other alternatives include proceeding with re-performance of the LLRT of IMC-042.

These options, which were rejected, can involve more extensive environmental impacts than the proposed temporary exemption to defer the LLRT of IMC-042 until the next scheduled refueling outage. Thus, the principal alternative would be to deny the requested temporary exemption which would require the LLRT for IMC-042 to be performed prior to the riext scheduled refueling outage.

Alternative Use of Resources The proposed temporary exemption does not involve the use of any resources not previously considered in the " Final Environmental Statement Related to the Operation of Clinton Power Station, Unit 1," dated May 1982.

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