B14293, Forwards one-time Schedular Exemption from Requirements of 10CFR50,App J from Type B & C Requirements

Forwards one-time Schedular Exemption from Requirements of 10CFR50,App J from Type B & C Requirements

ML20127K912
Person / Time
Site:	Millstone
Issue date:	01/18/1993
From:	Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
B14293, NUDOCS 9301260269
Download: ML20127K912 (20)

Text

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NORTHEAST UTILITIES o.nor.i Omc.. . s.io n sir i. s.,iin. Conn.ciicui l E'!'ISN'IN L ' U[NY.$ 'N J w.w -...um P.O. BOX 270 HARTFORD. CONNECTICUT 06141-0270 (203) 665-5000 January 18, 1993 Docket No. 50-245 B14293 Re: 10CFR50.12 10CFR50, Appendix J U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Gentlemen:

Millstone Nuclear Power Station, Unit No. I 10CFR50, Appendix J '

Request for Schedular Exemption From Tyne B and C Test Reauirements Pursuant to 10CFR50.12, Northeast Nuclear Energy Company (NNECO) hereby requests a one-time schedular exemption from the requireme,its of 10CFR50, Appendix J, Sections III.D.2(a) and III.D.3, on behalf of Millstone Unit No. 1. This exemption would provide temporary relief from the 2-year schedular requirement associated with Type B and C periodic local leak-rate tests (LLRT) and allow the tests to be performed during the Cycle 14 refueling outage. As defined in 10CFR50, Appendix J, Sections III.D.2(a) and Ill.D.3, Type B and C LLRTs are required to be performed " . . . in no case at inter-vals greater than 2 years. . . . "

On April 7, 1991, NNECO commenced the most recent containment LLRT program at Millstone Unit No. 1 in accordance with 10CFR50, Appendix J, Type B and C periodic test requirements. As a result of the unusually long 1991 (Cycle 13) refueling outage, a shutdown for licensed operator requalification training and erosion / corrosion inspections, and an unplanned shutdown for service water system piping inspections and repair, the Cycle 14 refueling outage has been rescheduled from February 1993 to approximately February 1994. The requirement to perform Type B and C LLRTs within a 2-year interval would require a plant shutdown during Cycle 14 solely to perform LLRTs, given the current Millstone Unit No. I refueling outage schedule. Such a shutdown would result in an increase in occupational radiation exposure and would entail a significant expenditure of resources. Thus, the subject exemption is being 3 requested to gain relief from the schedular requirements of 10CFR50, Appendix J, Sections III.D.2(a) and III.D.3 in order to permit realignment of the LLRT program with the Millstone Unit No. I refueling outage schedule. Approval'of I this request will also benefit the Millstone Unit No. 1 ALARA program by l 9301260269 930118 PDR P

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t.S. Nuclear Regulatory Commission B14293/Page 2 January 18, 1993 eliminating the additional personnel exposure which would accrue during the performance of these tests prior to the Cycle 14 refueling outage. Details of our exemption request are contained in Attachment 1.

The Commission's regulations, specifically 10CFR50.12(a), provide that exemp-tions may be granted from the regulations in 10CFR50 provided that they are

" authorized by law, will not present an undue risk to the public health and safety, and are consistent with the common defense and security." The NRC has granted similar Appendix J exemptions to other plants, including the Haddam Neck Plant and the Browns Ferry Nu lear Plant, Unit 2 by letters dated August 28, 1991,") and June 10,1992,'p) respectively.

Based on the information provided in Attachment 1, NNECO concludes that an exemption from the requirements of 10CFR50, Appendix J, Sections Ill.D.2(a)-

and III.D.3 is justified for Millstone Unit No. I pursuant to 10CFR50.12, Sections (a)(1), (a)(2)(ii), (a)(2)(iii), and (a)(2)(v).

It is our understanding that the NRC is in the process of amending 10CFR50, Appendix J, to update the criteria and clarify questions of interpretation with regard to leakage. rate testing of containments of nuclear power plants.

Among major modifications proposed to Appendix J, the revised rule contemplates changes in Type A, B, and C test frequencies. Specifically, based on the trend from 18-month toxard 24-month refueling cycles, the wording in the proposed rule may be revised to provide greater flexibility in this area. The exemptions proporad herein are consistent with'the intent of these contemplated changes.

Moreover, it is noteworthy that 10CFR50, Appendix J is one of the regulatory requirements which is under review within the program -to eliminate requirements marginal to safety. Subsequent to a 1984 NRC initiative to identify specific regulatory requirements and associated regulatory positions that needed reevaluation, seven areas were selected for analysis from a list of 45 candidates. The seven selected areas were chosen based on the potential benefit for licensees and the number of plants affected. Included as one of the seven selected areas was Appendix J. The February 4, 1992 Federal Reaister Notice (57FR4166) regarding " Elimination of Requirements Marginal to Safety," stated:

(1) A. B. Wang letter to E. J. Mroczka, " Exemption to Appendix J - Extension of the Type B and C leak Rate Test Period," dated August 28, 1991.

(2) F. J. -Hebdon letter to M. O. Medford (Tennessee Valley Authority),"

Browns Ferry Nuclear Plant Unit 2 - Issuance of Exemption to 10CFR Part 50, Appendix J, Sections Ill.D.2(a) and III.D.3 (TAC No.-M82365)," dated June 10, 1992.

U.S. Nuclear Regulatory Commission B14293/Page 3-January 18, 1993 The effects of selected eliminations or modifications to the regulations were evaluated in terms of such factors as public risk and costs to industry and NRC. The results indicated that potential modifications of the regulatory requirements in all the areas except charcoal filters would have little impact on risk...

The cost analyses indicated that substantial savings in operating costs may be realized in the areas of containment leakage rates...

As a result, it' is our understanding that the allowable containment leakage rate utilized in containment testing may be increased.

Additionally, the February 4, 1992, Federal Reaister Fotice stated that

" Decreasing the prescriptiveness of some regulations may improve their effectiveness without reducing safety." Specifically, 10CFR50, Appendix J was identified as a regulation which could be made less prescriptive. The Federal fkoister Notice provided the conclusion that:

The detailed and prescriative technical requirements contained in these regulations could )e removed and replaced with performance-based requirements and supporting regulatory guides.

Our proposed exemption to Appendix J is consistent with the overall approach contemplated within the program to eliminate requirements marginal- to safety.

While NNECO is not proposing an increase in allowed containment leakage, our approach to meeting Appendix J and maintaining and improving containment integrity is founded in a performance-based approach.

Evaluations indicate that there has been a history of good LLRT performance, with the exception of penetration X-25/2020 which has failed its "As-Found" tests during several refueling outages. We believe that it is most appropriate to focus resources and attention to penetrations with a history of increased leakage. Accordingly, penetration X-25/2020 will be tested during Cycle 14 to confirm that previous corrective actions have been effective. As such, no exemption is being requested for this penetration. We believe that there would not be any substantial benefit to safety of performing LLRTs on the o.ther penetrations whose tests have been consistently acceptable.

Furthermore, any potential incremental benefit 'would not be sufficient to offset the increased radiation exposure and other- risks associated with performing a number of these tests at power, or the undue burden of a forced outage during Cycle 14 to perform the testing while shut down.

In summary, NNEC0 has - concluded that the -exemption request detailed in Attachment 1 is warranted under. the standards of 10CFR50.12. Additionally, NNECO has taken prudent steps to improve the containment integrity of Millstone Unit No. I and has made a good-faith effort to satisfy the requirements of. Appendix J. Improvements have been made to reduce individual penetration leakage rates, along with a continuing effort to identify and repair penetrations which have the potential for- degraded performance.

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U.S. Nuclear Regulatory Commission B14293/Page4 January 18,-1993 NNECO's ongoing commitment to improve containment

• integrity was fully described in- our letter dated November 4, 1992. Our efforts in wer affirmed by -the Staff- -in letters. dated this regard 11, 1993. g"5,al January so respectfully requests that a schedular NNECO exemption to 100FR50, Appendix J, Sections. III.D.2(a) and III.D.3 ba granted prior to April 6, 1993, which is the earliest expiration date of the 24 calendar month test interval for any individual penetration.

We trust you will find this information satisfactory, and we remain available to answer any questions you may have.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

.$[GA J

J. F. (OgaExecutiveVicePr]esident cc: T. T. Martin, Region I Administrator

-J.-W. Andersen, NRC Acting Project Manager, Millstone Unit No. 1 P. D. Swetland, Senior Resident Inspector, Millstone Unit Nos. 1, 2, and 3-i

-(3) J.: F. Opeka letter to U.S. Nuclear Regulatory-- Commission, "10CFR50,-

Append.ix J, Type A Testing--Re' quest for Exemption from Schedular.

._ Requirements," dated November 4, 1992.

(4) J.-W -Andersen letter to J. F. Opeka, " Millstone Nuclear Power Station,- '

-Unit 1 '-- Exemption to 10CFR50,- Appendix J --(TAC No. .M84727)," - dated - .

' January _ 11,~1993.

(5): -J. W. Andersen" letter to J. F. Opeka, " Issuance: of Amendmeat-(TAC.No. M84727)," dated ~ January 11 .1993. ,

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Docket No. 50-245 -!

B14293 f

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l. Attachment 1 Millstone Nuclear Power Station, Unit No. 1 4

10CFR50, Appendix J

. Equest for Schedular Exemption From T,;e B and C Test Requirements f

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4 U S. Nuclear Regulatory Commission B14293/ Attachment 1/Page 1 January 18, 1993 i

Millstone Nuclear Power Station, Unit No.1 10CFR50, Appendix J Request for Schedular Exemption From j Tvoe 8 and C Test Reovirements EXEMPTION RE00EST i

j Section III.D.2(a) of 10CFR50, Appendix J, requires that:

Type B tests, except tests for air locks, shall be performed during reactor shutdown for refueling or other convenient intervals but in no case at intervals greater than 2 years.

Section III.D.3 of 10CFR50,- Appendix J, requires that:

fype C tests .shall be performed during each reactor shutdown for efueling but in no case at intervals greater than 2 years.

ant to 10CFR50.12, NNECO requests that a one-time schedular exemption

.iom the requirements of Appendix J, Sections III.D.2(a) and III.D.3 be granted to Millstone Unit No.1 to provide temporary relief from the two-year requirement associated with Type B and C periodic local leak-rate tests (LLRT). This exemption request applies to the testing of all penetrations, i except X-25/202D, .and would allow the LLRTs to be performed during the Cycle 14 refueling outage.

On April 7, 1991, NNECO commenced the most recent containment LLRT program at Millstone Unit No.1 in accordance with 10CFR50, Appendix J, Type B and. C periodic test requirements. As a result of the unusually long 1991 (Cycle 13) refueling outage, a -shutdown for licer. sed operator requalification training and erosion / corrosion inspections, and an unplanned shutdown for service water system piping inspections and ' repair, the Cycle 14 refueling outage has been rescheduled- from February 1993 to approximately February 1994. . We note that this date could change due to operational requirements, capacity factor, or an

unscheduled outage. The requirement-to perform Type-B and C LLRTs within a 2-

! year interval would require .a plant shutdown during Cycle 14-solely to perform LLRTs, given the current Millstone UnitLNo. I refueling outage- schedule. The exemption is being requested to prevent a mid-cycle shutdown and to allow performance of the LLRT program during the Cycle 14 refueling outage.

DISCUSSION The two-year interval specified in Appendix J is intended to be frequent enough to prevent significant degradation from occurring .and long enough to permit LLRTs to be performed during refueling outages. At the time 10CFR50, Appendix J was- published as a final rule (February 14, 1973, 38FR4305), all light water reactors were on a nominal' annual refueling cycle with relatively

'U.S. Nuclear Regulatory Commission B14293/ Attachment 1/Page 2 January 18, 1993 short refueling outages. Today many light water reactors are on an 18-month to two-year refueling cycle. The intent of the regulation is for isolation valves to be tested during refueling outages, not to require the unit to be shut down solely for performance of LLRTs.

Performing LLRTs during refueling outages lowers radiation exposure to plant personnel and is consistent with the purpose of 10CFR Part 20. A shutdown solely to perform leak tests during Cycle 14 is not consistent with the intent of either Appendix J or 10CFR Part 20 and would result in at least doubling the radiological exposure and the risks associated with the affected ' tests.

Since the tests would be performed again during the Cycle 14 refueling outage (to minimize the potential for a mid-cycle shutdown or a schedular exemption request during Cycle 15), the cost to personnel in terms of- radiological exposure and personnel safety is greater than the modest increase in assurance that the components will not significantly degrade during the remainder of. the operating cycle.

It is noted that most of the components associated with -this schedular exemption request cannot be tested at power due to their intended function and/or location. The minimum time required-to perform the_ entire Type B and C test program during a mid-cycle outage is estimated to be approximately. five weeks. This mid-cycle outage would be performed with the fuel in the vessel and would involve the following considerations:

1. Several of the LLRT procedures require draining of emergency core cooling system pathways. While this evolution could be conducted with-fuel in the vessel, it does pose additional challenges with respect tn managing shutdown risk. Normal refueling practice involves a full core offload which maximizes system availability for testing.

2. A heatup and cooldown cycle would be added, increasing the probability of undesirable events more likely to occur during such evolutions.

3. A significant amount of personnel resources would be required to be expended to rewrite existing Lt.RT and system operating procedurcs to accommodate unusual system configurations that may - be required to be utilized, due to the fuel remaining in the vessel.

4. The length of the testing outage could be lengthened due to decay heat removal considerations, since the Shutdown Cooling System 'would be required to be removed from service to be tested.

5. Removal of the drywell head shield plugs and the drywell ' insulation package must be performed to reach a single two-inch check valve (HS-5) in the Head Spray System. It is~ noted that this particular valve is not operated during the cycle, thus minimizing the possibility of leakage.

Additionally, the above-described evolution is normally only conducted during refueling outages.

'U S. . Nuclear Regulatory Commission

, B14293/ Attachment 1/Page 3 January 18, 1993 i EVALUATION j A review of historical Millstone bnit No.1 LLRT data indicates that there has

, been overall good LLRT performance, with the exception of penetration X-25/2020 which has failed its "As-Found" tests during several refueling

, outages. Specifically, since 1982 NNEC0 has conducted six Type B and Type C tests as required by 10CFR50 Appendix J, Sections III.D.2(a) and 111.D.3.

During these six tests, a total of 18 different penetrations (out of a total

of 98 penetrations) have ever exceeded the Technical Specification requirements for individual penetration leakages (11.5 SCFH for main steam isolation valves and 18.8-SCFH fo- all other penetrations and valves).

Millstone Unit No. 1 is somewhat unusual in that Technical Specifications

provide an individual leak rate for each penetration. Detailed information i related to these 18 penetrations is provided -in Attachment 2. Aggressive-action to repair and prevent penetration failures has successfully led to only one penetration as a current repetitive failure (penetration X-25/2020).

Penetration X-25/202D (Atmospheric Control System Valves AC-7 through AC-12) is a multi-valve penetration, which when exposed -to LLRT conditions, subjects all associated valves to the test pressure of 43 psig. This multi-valve penetration is treated as a single penetration with an acceptance criterion of 18.8 SCFH (0.045 wt.%/ day) per Technical Specification Surveillance i Requirement 4.7.A.3.e(1)(b). A detailed discussion of the corrective actions taken to address the failure of the Atmospheric Control System valves was provided in a letter dated November 4,1992, and is included as Attachment 3

for the Staff's convenience.

The fact that none of the penetrations tested since 1982_have been inadequate i performers in terms of failing the 0.6 L, LLRT acceptance criterion, with the 4

exception of penetration X-25/2020, demonstrates the effectiveness .of the Millstone Unit No. 1 LLRT program in maintaining containment integrity.

Additionally, only .;netration X-25/2020 has failed to meet the LLRT acceptance criterion ty an amount large enough to have an impact on the "As-Found" ILRT results. It should be noted that a penetration that fails to meet its acceptance criterion and reported as a failure to the NRC via 10CFR50.73, cannot, in ' itsel f, be taken as an indication that; the containment is not sufficiently leak tight and would fail to meet the total acceptance criterion for all penetrations -of 0.6L, (300.3 SCFH). Using the minimum pathway leakage method of determining penetration leakage, the 1991 ILRT "As-Found" test would-have passed with a substantial margin if penetration X-25/202D was not included. As was the case in 1987, had valves' IC-6 and IC-7 been testable under the LLRT program and therefcre individually tested and repaired prior to the ILRT, the 1987 '"As-Found" ILRT would have passed. This demonstrates that the Type B and C LLRT program is very effective at Millstone -Unit No.1. By identifying and taking immediate corrective action on penetrations that could degrade containment integrity, _ Millstone Unit No. .I has improved overall containment integrity as indicated by the last two ILRT "As-Left" reported test results.

'U S. . Nuclear Regulatory Commission 1 B14203/ Attachment 1/Page 4 January 18, 1993 The "As-Left" ILRT results for tests performed in 1994, 1987, and 1991 are as

follows:

Reported Allowable Millstone Unit No. I "As-Left" Operational Maximum Allowable

, ILRT Results leak Rate Leak Rate (wt.%/ day) (wt.%/ day) (wt,%/ day) l 1984 0.779 0.9 1.2 i 1987 0.441 0.9 1.2 1991 0.4077 0.9 1.2 The above results are indicative of the . improvements in overall containment integrity. Additionally, the results of the 1987 and 1991 test show a leakage rate for the containment "As-Left" condition which is less than half of the 10CFR50, Appendix J, operational limit of 0.9 wt.%/ day, and approximately-f one-third of the Technical Specification maximum allowable leak rate of f 1.2 wt.%/ day. Moreover, the total Type B and C "As-Left" leakage result from 4

the 1991 refueling outage is 137.63 SCFH, which is approximately 46% of the

! Technical Specification limit of 300.3 SCFH. These results demonstrate that the containment is being left in an . increasingly more leak tight condition

prior to the start of each operating cycle and supports our position that a j schedular exemption is justified.

We believe that it is most appropriate to focus resources and attention to

, penetrations with a history of increased leakage. Accordingly, it is

currently our intention to test penetration X-25/202D in_ late April 1993 to 4

confirm that previous corrective actions have been effective. It is noted i that the most recent LLRT of this penetration was performed on June 22, 1991.

We believe that there would not be any substantial benefit to safety of

. performing LLRTs on the other penetrations whose tests have been consistently acceptable. Furthermore, any potential incremental benefit would not be sufficient to offset the increased radiation exposure and other risks

associated with performing a number of these tests at power, or the undue j burden of a forced outage during Cycle 14 to perform the testing while shut down.

Based on the past performance of the affected components, as indicated'by the consistently low "As-Found" leakage rates, there is reasonable assurance that no significant degradation would occur during the extension interval. . -The i

"As-Found" leak rate, minus the major contributor tso the failures, was 0.623 and 0.619 wt.%/ day for the 1987 and 1991 ILRTs, respectively. Substantial margin existed between these values and the Technical Specification maximum allowable leak rate of 1.2 wt %/ day. The condition of the compnnents is, therefore, not expected to change significantly over the extension period of approximately 10 to 11 months.

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'U.S. Nuclear Regulatory Commission B14293/ Attachment 1/Page 5 January 18, 1993 Furthermore, the two-year interval specified for Type B and Type C tests was based on two years of exposure to service conditions. For the months prior to startup and the months when the plant was shut down during the current cycle, i

these components were not exposed to service conditions. This further minimizes the safety implications of this request.

@ lTH LGATION OF EXEMPTION NNECO concludes that the exemption from the requirements of 10CFR50, Appendix J, is justified pursuant to 10CFR50.12, entitled, " Specific Exemptions," Sections (a)(1), (a)(2)(ii), (a)(2)(iii), and (a)(2)(v) in that:

• This exemption "will not present an undue risk to the public health and safety."

In general, the intent of the Commission's regulations . and otner NRC requirements is to provide reasonable assurance- that operation of nuclear power plants does not pose an undue risk to the health and safety of the public. The intent - of specific regulations such as 10CFR50, Appendix J, is to set standards which will provide reasonable assurance that the individual contributions to risk posed by specific issues or concerns will be low, such that overall plant risk remains acceptably low. While compliance with the regulaticns will, for the most part, provide reasonable assurance that plant -operation does not pose undue risk to the publ ic, noncompliance does not necessarily represent an unacceptable risk. In this specific case, exceeding the 2-year LLRT interval to accommodate the Millstone Unit No. I refueling outage schedule does not represent an unacceptable safety risk nor irreversible environmental consequences since there is reasonable assurance that containment _ integrity will be maintained. Furthermore, the proposed schedular exemption does not change, modify, or restrict -

existing plant safety limits, safety settings, systems, or operations.

The proposed schedular exemption does not impact the design basis of containment or modify its response during a design basis loss-of-coolant accident.

• " Application- of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of- the rule."

The intent of Type B and C local leak-rate testing is to ensure that the -  ;

containment leak-tight integrity is maintained within the requirements specified in plant Technical Specifications during operating . cycles.

The time interval of 2 years is based in part on the expected i degradation of components exposed to- the environment resulting from- a full 24 months of normal plant operation. For the months prior to startup and.the months when the plant was shut down during the current cycle, these components were not exposed to service ' conditions.

Moreover, we believe the incremental increase _in leakage due to an

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! 'U.S. Nuclear: Regulatory Commission

! B14293/ Attachment 1/Page 6 4 l January 18, 1993-i 1 j ._

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- extension will. be small. The _ exemption _ is -being- requested Lto address

- -the schedular implications associated with an extended 19911.

refueling outage, a shutdown for operator requalification _ training. :and

- erosion / corrosion inspections, and ' an unplanned shutdown for service -

water -piping inspections and' repairs. The: proposed schedular exemption l-does' not impact the Type B and C test pressure or' the maximum allowable -

i leakage rate and only affects the associated schedular- requiremen_t. In addition, f based ' on our aggressive corrective action- plan, there is 4 reasonable assurance that the containment leakage-limiting-function will lL be maintained. Therefore, NNECO believes the _ underlying.. intent of the J

rule would continue to- be meti l * " Compliance would result in costs--that :are significantly! in excess of.

those contemplated when the regulation was adopted."

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b Current replacement' energy costs associated with a' premature or extended.  !

i shutdown in' order to comply with the two-year LLRT-. interval were not '

contemplated when' the regulation-was adopted, .nor was it the_ intent of :

the regulation to force a shutdown' solely to- perform 1 Type B and C testing. A requirement- to

shut down to perform LLRTs, evu, though

! judgment indicates that 'the' incremental increase -in' leakage due: to' the

!- extension of the test interval to the next scheduled refueling outage is

minimal, would _ represent undue hardship

and excessive costs in the form i of increased personnel-radiological. exposure, lost revenues,-and higher i costs associated with performing the:LLRT program.twiceiduring Cycle .14.

* "The exemption would provide only- temporary l relief from- the applicable:

regulation: and the licensee or applicant has made. good-faith effor.ts to i comply.with the regulation."

!- 'This exemption applies to the next- series 'of Type B 'and C tests ' only.

The length of the current Millstone Unit No.1 fuel cycle, combined withL

[ the unanticipated _ delay in plant startup .from the 1991.' refueling outage L and unscheduled Cycle-14-plant shutdowns, are the reasons this schedular.

!- exemption is~necessary. Strict schedular compliance to the' 2-year LLRT

[ interval will impact refueling outage-schedules in order to' accommodate local leak-rate. testing and would require an unnecessary shutdown, L

1 i CONCLUSION-

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NNECO has concluded thatL"special circumstances" are present and that this

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11 F schedular exemption requestLis warranted under the . standards' of"10CFR50.12.

Tnereiis a high degree of confidence that the' affected components will not.

i significantly. degrade Lduring the: extended operating. interval. :-Moreover, we.

, -believe~ that any potential" incremental benefit ofLperforming. the. tests within?

. the 1 two-calendar-year requirement would not be sufficient to < offset. the

? ' increased radiation exposure to personnel . performing the' LLRTs, or the: undue. c

, > financial. burden of_ a- forced outage during Cycle _14 Loperation.

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J Docket No. 50-245-B14223 l

i- Attachment 2 l Millstone Nuclear Power Station, Unit No.1

10CFR50, Appendix J Request for 3chedular Exemption From Type B and C Test Requirements Penetrations that Exceeded Technical Specification Requirements For Individual Leakages Since 1982 1

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'U.S. Nuclear Regulatory Commission i B14293/ Attachment 2/Page 1 January 18, 1993 i

i Millstone Nuclear-Power Station, Unit No.1

- Penetrations that Exceeded 5

Technical Specification Requirements For Individual Leakaaes Since 1982 i

Penetration Valve As-Found Wt.%/ Day Nin Palb Wt.%/ Day

1282

$ X-47 1-RR-36 41 SCFH .098 20.5 SCFH 0.049 l-RR-37 j X-25/202D l-AC-7_ 41 SCFH -098

. See-Note Below t

1-AC-8 1-AC-9 l-AC-10 i 1-AC-11

1-AC-12

! X-9A 1-FW-9A 1-FW-10A 70 SCFH .168 35 SCFH .084 i

X-42 1-SL-7 47 SCFH .113 47 SCFH .113 lb84 X-7B l-MS-1B l-MS-2B 20.29 SCFH .049 10.15 SCFH .024 X-7C' l-MS-lC 1-MS-2C 20.06 SCFH .048 10.03 SCFH .024 X-14 1-CV-2 l-CU-2A i 1-CV-3 1-CU-5 31.89 SCFH .076 15.95 SCFH .038 s

1985 1

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X-7A 1-MS-1A 16.27 SCFH .039 8.14 SCFH .020 1-MS-2A Note: No Minimum Path value was determined. For - conservati sm, the Minimum i: Path value would be no more than one-half of the "As-Found" value.

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'U.S. Nuclear Regulatory Commission B14293/ Attachment 2/Page 2 January 18, 1993 Penetration Valve As-Found HL.%/ Day Mi.n Path Wt.%/ Day l 1985 (Continued)

I X-70 1-MS-10 16.28 SCFH .039 8.14 SCFH .020 1 1-MS-20 X-14 1-CU-2 73.68 SCFH .177 36.84 SCFH .088 4 1-CV-2A

, 1-CV-3

l-CV-5 X-205 1-AC-2A- >73.7 SCFH >0. 6 L, 1-AC-3A i X-205 1-AC-2B >73.7 SCFH >0.6L, t

1-AC-3B

X-25/202D l-AC-7 >73.7 SCFH >0. 6 L, 1-AC-8

1-AC-9

! 1-AC-10

l-AC-11

] 1-AC-12

X-26/205 1-AC-4 >73.7 SCFH >0. 6 L, i 1-AC-5 1-AC-6 1-AC-17 1

H81 X-7B l-MS-1B 16.18 SCFH .039 ~8.09 SCFH .019 l-MS-28 X-14 1-CV-2 >0.6L, 8.67 SCFH .021

l-CV-2A 1-CV-3

+

1-CV-5

. X-16A 1-CS-5A 19.92 SCFH .048 19.92 SCFH .048 X-17 1-HS-4 >0.6L, 0.0 SCFH .000 1-HS-5 X-12 1-PAS-17 60.1 SCFH .144 0.00 SCFH .000 1-PAS-20 4

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'U.S. Nuclear Regulatory Commission B14293/ Attachment 2/Page 3 January 18, 1993 Egnetration Valve As-Found Wt.%/ Day -Min Path Wt.%/ Day 1987 (Continued)

X-25/2020 1-AC-7 >0.6L, 11.44.SCFH . 0 ?.7 1-AC 1-AC-9 l-AC-10 1-AC-11 1-AC-12 1982 X-25/202D l-AC-7 >0.6L, 56.35 SCFH .135 .b 1-AC-8 1-AC-9 1-AC-10 1-AC-11 1-AC-12 X-14 1-CU-2 >0.6L, 18.80 SCFH .045 1-CV-2A 1-CU-3 1-CU-5

1. 3 GIBBS MANWAY 63.00 SCFH .151 31.50 SCFH .07G

.13.91 X-25/202D l-AC-7 >0.6L, 1-AC-8 1-AC-9 l-AC-10 1-AC-12 X 1-HS-4 >0.6L, 0.02 SCFH .001 1-HS-5 X-8 1-MS-5 68.94 SCFH .165 .0.165 SCFH .001 1-MS-6 X-9A 1-FW-9A 83.50 SCFH .200 0.02 SCFH .001 1-FW-10A

1. 1 GIBBS MANWAY 29.75 SCFH .071 14.89 SCFH .036

1. 8 GIBBS MANWAY. 57.40 SCFH .138 28.70 SCFH .069

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. B14293/ Attachment 2/Page 4 January 18, 1993 i Even though .there were 18 different penetrations that did not meet their required acceptance criterion based on maximum path leakage (11.5 SCFH at i 25 psig for main steam is91ation valves. and 18.8 SCFH at 43 psig for all-other -

valves and penetrations), only 9 penetrations failed to meet their individual penetratior, acceptance criterion under the minimum path- method. Millstone i

! Unit No. 1 is somewhat unusual in that Technical Specifications provide an l individual penetration leak rate limit for each penetration. Moreover, it should be noted that a' penetration that fails to meet its acceptance criterion I

and reported as a failure to the NRC via 10CFR50.73, cannot in itself be taken as an indication that the containment is not sufficiently leak tight and would fail to meet the total acceptance criterion for all penetrations of' O.6L, 2

(300.3 SCFH).

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, Docket No. 50-245 '

B14293

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! Attachment 3 l

Millstone Nuclear Power Station,. Unit 1No. 1 i 10CFR50, Appendix J

Request for Schedular Exemption From l Type B and C Test Requirements i

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Corrective Actions Taken to Address Atmospheric Control System Valves

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January 1993 i

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'U.S. Nuclear. Regulatory' Commission i B14293/ Attachment 3/Page 1 l 3

January 18, 1993 ,

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! -Millstone Nuclear Power. Station, Unit'No.-1

- Corrective Actions Taken to Address j Atmospheric Control System Valves i

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l Penetration X-25/202D (Atmospheric Control - System- Valves AC-7 through AC-12) -

has failed its local leak-rate tests .(LLRTs)

for the; following years: _1982, i 1985, 1987, 1989, and 1991. 'In: addition, penetration X-26/205 ;(Atmospheric

_ Control System Valves AC-4; AC-5;- AC-6; AC-17) failed the. LLRT during the:1985 i refueling- outage. Penetrations X-25/2020 and X-26/205 'are multi-valve j -penetrations' When an LLRT is performed on these penetrations, all of their-l associated valves are subjected to the test pressure of 43 psig. - These multi-l valve penetrations are each treated as'a-single penetration with an acceptance L critcrion of_ 18.8 SCFH (0.045 wt.%/ day) . per Technical _ Specification

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Surveillance Requirement 4.7.A.3.e(l)(b)- .

l The 1991' "As-Found"- integrated leak rate test - (ILRT) failed as a result. of i excessive Type _ C leakages experienced from. penetration ' X-25/2020. - Although

! other penetrations did not meet the individual penetration LLRT leakage r_ ate -

l acceptance criterion in 1991, these other penetrations only sl.ightly exceeded.

l the ILRT acceptance 1 criterion and their combined leakages were. not the identifled ' contributor to the 1991 "As-Found":ILRT- failure.

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l Through extensive investigation and' testing, two_ ' problems were identified as i the probable cause for the continued poor performance 1 ofo penetration

!: X-25/2023. This paragraph discusses the corrective act a ns takensto -address the first problem and we discuss below the corrective acdons taken to address i the second-problem. _ The first problem noted was that- there was_ a slight shift-L in- the actuator mounting bracket -each . time .the valve was cycled. . This i

shifting affected the repeatability of the: valve closing position and as a l' result,- consistent values- for leakage rates could notbe established. :Since l- the actuator is_ fixed to the valve-through a tube. steel mounting. bracket, .and i the bracket- is' attached to the valve using = onlyi two mounting' bolts, -the

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F clearance in the bolt holes in- the bracket 1allowedj a _ slight shifting of. the actuator relative. to the valve. Two modifications: were made to all mounting l brackets for the Atmospheric. _ Control' System ' butterfly- valvess for penetration -

X-25/202D. Thei first _ modification; was to pin: the mounting bracket to the-j valve body using two 1/4" stainless l steel ~ dowel pins to prevent. shifting of

- the bracket. The second modification was to add stiffeners to the tube steel

! bracket to preclude any possibility' of buckling - that could . affect the valve - -

, closure position.- Similar1 modifications are planned for the Atmospheric-L Control-System valves on penetration X-26/205'(ValvesiAC-4; AC-5; AC-6; AC-17)-

l and will - be ' accomplished during the Cycle.14- -refueling . outage to further i

! enhance its ability to. meet LLRT acceptance criteria.

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'U.S. Nuclear Regulatory Commission B14293/ Attachment 3/Page 2 January 18, 1993 In addition, during the modification of Valves AC-3A and AC-10, it was noted that the carbon steel vane of the valve had a " scale" buildup producing a rough surface. The design of these valves is such that the vane slides into the seat ring to effect the full closure position. The rough surface on the vane could act as an abrasive surface, ...d over several cycles of -operation would result in the deterioration of the Nordel seat ring. The carbon steel-vanes for these two valves were replaced with stainless steel vanes. During the next scheduled refueling outage, as part _of the plan to _ improve the reliability of penetrations X-25/202D and X-26/205, the carbon steel vanes in the remainder of the Atmospheric Control System valves wili be removed and replaced with stainless steel vanes.

Excessive maintenance problems had been experienced with Valves AC-9 and AC-12 (2" Dezurik plug valves). Therefore, these plug- valves were replaced during the _1991 refueling outage with new valves as part of the program for maintaining the integrity of this penetration.

We believe that with the corrective action taken on penetration X-25/202D, along with planned modifications to the remainder of its associated valves, this penetration will maintain its containment isolation function. As discussed above, the Atmospheric Control System valves associated with penetration X-26/205 will also have their valve vanes replaced and will undergo mounting bracket modifications, thereby improving the reliability of the penetration.

It was noted above that the vane of Valve AC-3A was replaced in 1991. Valves AC-3A and AC-3B are associated with penetration X-205. However, this penetration did not contribute to the 1991 "As-Found" LLRT failure. The vane of Valve AC-3B will also be replaced during the next refueling outage. The vanes for these valves require replacement because the valves are prone to the same " scale" buildup problem experienced with the other Atmospheric Control System butterfly valves.

The appropriateness of the above-mentioned plan was affirmed by the Staff in a [[letter::B14245, Submits Info to Resolve NRC 921106 Comments on Util 901221 & 910321 Responses to GL 90-06, Resolution of GI 70, 'Porv & Block Valve Reliability' & GI 94, 'Addl Low Tempr Overpressure Protection for Light-Water Reactors.'|letter dated January 11, 1993]]. The NRC stated:

The licensee's justification for the proposed exemption [ relief from accelerated ILRT frequency] is that the Type A tests failed in the "As-Found" condition in 1987 and 1991 because of a few specific penetrations. These penetrations have (except for. one) been demonstrably corrected; corrective action has been taken on the remaining penetration, but the success of the co rective action has not yet been fully confirmed. For the one potentially questionable penetratior., the licensee will Further, additional corrective actionperform mid-cycle will Type at be taken C . hetesting.

t next refueling outage. The NRC staff has' reviewed the test reports- and the licensee's proposed and implemented CAP. The-NRC staff finds that the licensee has identified the problem penetrations that caused the Type A ,

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January.18,.1993 i

i-t test failures in 1987 and 1991, and has instituted an ' effective CAP to l address these- problems. There is reasonable assurance that the

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i containment leakage-limiting function will be maintained and the staff j finds that a forced outage to. perform a Type A test is not necessary.

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