CNRO-2005-00002, Request for Alternative ANO2-R&R-008 - Use of Mechanical Nozzle Seal Assemblies

Request for Alternative ANO2-R&R-008 - Use of Mechanical Nozzle Seal Assemblies

ML050400108
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/24/2005
From:	Burford F Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNRO-2005-00002, TAC MB4517
Download: ML050400108 (10)

Text

Entergy Operations, Inc.

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1340 Echelon Parkway En tf*a Jackson, Mississippi 39213-8298 Tel 601-368-5758 F. G. Burford Acting Director Nuclear Safety & Licensing CNRO-2005-00002 January 24, 2005 U. S. Nuclear Regulatory Commission Attn.: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Request for Alternative ANO2-R&R-008 -

Use of Mechanical Nozzle Seal Assemblies Arkansas Nuclear One, Unit 2 Docket No. 50-368 License No. NPF-6

REFERENCES:

1. Letter from Entergy Operations, Inc. to the NRC dated March 15, 2002

2.

Letter to Entergy Operations, Inc. from the NRC (TAC No.

MB4517) dated July 3, 2002

3.

Letter from Entergy Operations, Inc. to the NRC dated December 20, 2004

Dear Sir or Madam:

In Reference #1, Entergy Operations, Inc. (Entergy) requested, via Request for Alternative ANO2-R&R-002, NRC authorization to use the new design of the mechanical nozzle seal assembly (MNSA-2) on various pressurizer nozzle locations at Arkansas Nuclear One, Unit 2 (ANO-2) for two (2) operating cycles. The staff granted this request, as documented in Reference #2. Entergy installed six MNSA-2 devices during the spring 2002 refueling outage at ANO-2 (2R15).

In Reference #3, Entergy requested that the NRC staff extend the temporary installation time period from the current two (2) operating cycles to three (3) operating cycles for the six MNSA-2 devices installed on the ANO-2 pressurizer during 2R15. This request was documented in Request for Alternative ANO2-R&R-008.

Representatives from Entergy and the NRC staff participated in a telephone call on January 19, 2005 to discuss Entergy's request. Based on that discussion, Entergy supercedes ANO2-R&R-008 as submitted via Reference #3 with a revised request contained in Enclosure 1.

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CNRO-2005-00002 Page 2 of 2 As stated in Reference #3, Entergy will replace the ANO-2 pressurizer during the fall 2006 refueling outage (2R18), thereby eliminating further need of the installed MNSA-2 devices beyond 2R18.

In the event a leaking pressurizer heater sleeve is discovered during the upcoming refueling outage at ANO-2 (2R17), Entergy may elect to install a MNSA-2 at that location. Such an installation would be performed in accordance with approved Request for Alternative ANO2-R&R-002.

Should you have any questions regarding this request, please contact Guy Davant of my staff at (601) 368-5756.

This letter contains commitments as identified in Enclosure 2. These commitments supercede those documented in Reference #3.

Very truly yours, FGB/GHD/ghd

Enclosures:

1. Request for Alternative ANO2-R&R-008

2. Licensee-identified Commitments cc:

Mr. W. A. Eaton (ECH)

Mr. J. S. Forbes (ANO)

Dr. Bruce S. Mallett, Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. D. G. Holland MS 0-7 D1 Washington, DC 20555-0001

ENCLOSURE1 CNRO-2005-00002 REQUEST FOR ALTERNATIVE ANO2-R&R-008

ENTERGY OPERATIONS, INC.

ARKANSAS NUCLEAR ONE, UNIT 2 REQUEST FOR ALTERNATIVE ANO2-R&R-008 COMPONENTS I IDENTIFICATION Components/Numbers:

ANO-2 Pressurizer (2T-1) heater sleeve nozzle locations C2, El, E2,, F4, GI, and N2 Code Class:

ASME Section 1I1, Class 1

References:

1)

ASME Section Xi, 1992 Edition with Portions of 1993 Addenda

2)

ASME Section 1II, 1989 Edition

3)

ASME Section 1I1, 1968 Edition through and including Summer 1970 Addenda

4)

Entergy Operations, Inc., Letter CNRO-2002-00012 to the NRC dated March 15, 2002

5)

NRC Letter to Entergy, Operations, Inc.

(TAC No. MB4517) dated July 3, 2002

6)

Westinghouse Design Report No. DAR-CI-02-02, Rev. 1, Addendum to CENC-1224 Analytical Report forArkansas Nuclear One Unit 2 Pressurizer Unit:

Arkansas Nuclear One, Unit-2 (ANO-2)

Inspection Interval:

Third (3rd) 10-year interval I1. CODE REQUIREMENTS The code of record for performing ASME Section Xl repair/replacement activities at ANO-

-2 is the 1992 Edition with portions of the 1993 Addenda (Reference 1) for pressure testing. ASME Section Xl IWA-4170 requires repairs and installation of replacements to be performed in accordance with the owner's design specification and the original construction code of the component or system. The affected pressurizer heater sleeves and nozzles were designed and constructed to the rules of ASME Section 1II, Subsection NB, 1968 Edition through and including the summer 1970 Addenda (Reference 3). Rules for replacing ASME Section 1II, Class 1 welded nozzles with mechanical clamping devices are not clearly defined by ASME Section 1II.

Ill. PROPOSED ALTERNATIVE In support of the spring 2002 refueling outage at ANO-2 (2R15), Entergy Operations, Inc.

(Entergy) requested, via Request for Alternative ANO2-R&R-002 (Reference 4), NRC authorization to use the improved design of the mechanical nozzle seal assembly, designated MNSA-2, for two (2) operating cycles. Entergy made this request to repair leaks attributed to primary water stress corrosion cracking (PWSCC) that are detected while performing inspections during refueling outages. The NRC approved Page 1 of 5

ANO2-R&R-002, as documented in Reference 5. Entergy installed six (6) MSNA-2 devices on leaking pressurizer heater sleeves (C2, El, E2, F4, GI, and N2) at ANO-2 during 2R15 in accordance with Request for Alternative ANO2-R&R-002 (Reference 4).

Pursuant to 10 CFR 50.55a(a)(3)(i), Entergy requests that the NRC staff extend the temporary installation time period from the current two (2) operating cycles to three (3) operating cycles for the six MNSA-2 devices installed on the ANO-2 pressurizer during 2R15. Entergy will replace the ANO-2 pressurizer in the fall 2006 refueling outage (2R18), at which time the MNSA-2 devices will no longer be needed.

Entergy will perform the following activities to support the one-cycle extension:

a. Pre-Service Inspection for MNSAs Installed Durinq Spring 2005 Refueling Outaae (2R17)

In the event a leaking pressurizer heater sleeve is discovered during 2R17, Entergy may elect to install a MNSA-2 at that location. Such an installation would be performed in accordance with approved Request for Alternative ANO2-R&R-002 (Reference 4). In addition to the requirements of ANO2-R&R-002, Entergy will perform the following activities to support the MNSA-2 installation:

1. Entergy will perform a VT-3 visual examination of the pressurizer in the area of installation in accordance with IWB-3520.21.

2. Entergy will perform a VT-1 visual inspection of pressure-retaining MNSA bolting prior to assembly. The acceptance standards of IWB-3517 shall apply.

3. Entergy will perform a VT-2 examination of the MNSA connection in accordance with Table IWB-2500-1 Category B-P with the insulation installed on the pressurizer.

b. Inservice Inspections for MNSAs Installed During 2R15 Since Entergy is replacing the ANO-2 pressurizer during 2R1 8 (2R1 8 is in the same interval and period as 2R17), those ASME inspections performed on a per-period or per-interval schedule are excluded from the inspections to be performed during 2R17. Entergy will perform inservice inspections on the six installed MNSAs during 2R17 as follows:

1. Entergy will inspect the leakage detection/diversion fitting for evidence of leakage before the other visual inspections are performed.

2.

If a MNSA-2 is required to be disassembled2, Entergy will perform a VT-I examination using the acceptance criteria of Table IWB-2500-1 Examination Category B-G-2. Additionally the VT-I inspection will be expanded to include 1 Although IWB-3520.2 is written specifically for the reactor vessel and its internal structures, application to the pressurizer is believed adequate to determine if conditions are acceptable for the installation of a MNSA-2.

2 In Entergy letter CNRO-2002-00018, Entergy committed to disassemble any MNSA-2 that was discovered leaking during the operating cycle and inspect it and the surrounding pressurizer surface for corrosion.

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the counterbore, female threads in the pressurizer (to the extent they are accessible), and the structural portions of the MNSA clamp, allowing no cracks.

3. With the plant at cold conditions, Entergy will perform a VT-2 and a VT-3 examination with the insulation removed from the MNSA-2 and surrounding areas of the pressurizer.

4.

Entergy will perform a VT-2 of the MNSA-2s with insulation installed during system leakage testing required by Table IWB-2500-1 Examination Category B-P during each refueling outage.

Upon NRC approval of this request, Entergy will revise the ANO-2 Inservice Inspection Program to include the above activities.

c. Other Actions If leakage from a MNSA-2 is detected during Cycle 18 operation, Entergy may elect to retorque the MNSA bolting to stop the leakage. However, if retorquing above the design limit becomes necessary, Entergy will perform an engineering analysis to revise the torque limit. If retorquing fails to stop the leak, Entergy will disassemble the MNSA-2 and examine it in accordance with Section lll.B.2, above and also perform a VT-3 examination with insulation removed. There shall be no evidence of leakage during plant startup.

IV. BASIS FOR PROPOSED ALTERNATIVE The specific details of the MNSA-2 description, design, and application were provided in Request for Alternative ANO2-R&R-002 (Reference 4), which was approved by the NRC staff (Reference 5). As stated in ANO2-R&R-002, the MNSA-2 device was designed for a 40-year life. The design of the MNSA-2 in combination with the proposed actions discussed in Section III provides reasonable assurance that:

1. The MNSA-2 will adequately perform its design function for one additional operating cycle; and

2.

Any degradation of a MNSA-2 device will be discovered and corrected prior to any gross failure of the reactor coolant pressure boundary.

V.

CONCLUSION 10CFR50.55a(a)(3) states:

"Proposed alternatives to the requirements of (c), (d), (e), (e, (g), and (h) of this section or portions thereof may be used when authorized by the Director of the Office of Nuclear Reactor Regulation. The applicant shall demonstrate that:

(i)

The proposed alternatives would provide an acceptable level of quality and safety, or (ii) Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety."

Page 3 of 5

Entergy requests NRC authorization to use the improved design of the MNSA-2 for one additional operating cycle as an alternative to removing the MNSA-2 devices from pressurizer heater sleeves and performing permanent weld repairs. Entergy will replace the ANO-2 pressurizer during the ANO-2 fall 2006 refueling outage (2R18) at which time no MNSA devices will be needed. Entergy believes that the additional inspection activities described in Section 1II, above, along with replacing the ANO-2 pressurizer, provide an acceptable alternative to removing the MNSA-2s and performing weld repairs on the associated pressurizer heater sleeves during upcoming ANO-2 refueling outage 2R17. Therefore, Entergy requests that the NRC staff authorize this request pursuant to 10 CFR 50.55a(a)(3)(i).

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Up" AI" Heater Sleeve MNSA-2 FIGURE 1 Page 5 of 5

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ENCLOSURE 2 CNRO-2005-00002 LICENSEE-IDENTIFIED COMMITMENTS to CNRO-2005-00002 Page 1 of I LICENSEE-IDENTIFIED COMMITMENTS TYPE (Check one)

SCHEDULED ONE-TIME CONTINUING COMPLETION COMMITMENT ACTION COMPLIANCE DATE

1. Entergy will replace the ANO-2 pressurizer v

Fall, 2006 during the fall, 2006 refueling outage (2R18).

(2R18)

2. In the event a leaking pressurizer heater sleeve Spring, 2005 is discovered during 2R17, Entergy may elect to (2R17) install a MNSA-2 at that location. Such an installation would be performed in accordance with approved Request for Alternative ANO2-R&R-002. In addition to the requirements of ANO2-R&R-002, Entergy will perform the following activities to support the MNSA-2 installation:

a. Entergy will perform a VT-3 visual examination of the pressurizer in the area of installation in accordance with IWB-3520.2'.

b. Entergy will perform a VT-1 visual inspection of pressure-retaining MNSA bolting prior to assembly. The acceptance standards of IWB-3517 shall apply.

c.

Entergy will perform a VT-2 examination of the MNSA connection in accordance with Table IWB-2500-1 Category B-P with the insulation installed on the pressurizer.

3. Upon NRC approval of this request, Entergy will Following NRC revise the ANO-2 Inservice Inspection Program approval to include the ISI activities specified in Section III.B.

1 Although IWB-3520.2 is written specifically for the reactor vessel and its internal structures, application to the pressurizer is believed adequate to determine if conditions are acceptable for the installation of a MNSA-2.