ML20128F661

Forwards Request for Addl Info Re Proposed Amend to Plant TS Re SG 24-month Insp Interval

ML20128F661
Person / Time
Site:	Millstone
Issue date:	10/01/1996
From:	Rooney V NRC (Affiliation Not Assigned)
To:	Feigenbaum T NORTHEAST UTILITIES SERVICE CO.
References
TAC-M92298, NUDOCS 9610080155
Download: ML20128F661 (5)

Text

<Mr. Ted C. Feigenbaum ~ October 1, 1996

'Executiva Vice President and Chief Nuclear Officer Northeast Utilities Service Company c/o Mr. Terry Harpster '

Director - Nuclear Licensing Services P.O. Box 128 Waterford, CT 06385 '

SUBJECT:

-REQUEST FOR ADDITIONAL INFORMATION ON PROPOSED AMENDMENT TO THE MILLSTONE UNIT 3 TECHNICAL SPECIFICATIONS REGARDING STEAM GENERATOR 24-MONTH INSPECTION. INTERVAL (TAC NO. M92298)

Dear Mr. Feigenbaum:

By letter dated May 1, 1995, you submitted an amendment request to the Technical Specifications (TS) for the Millstone Nuclear Power Station, Unit 3.

The amendment proposes a revision to the TS to permit plant operation on a 24-month fuel cycle. The surveillance interval for steam generator tube examinations must be modified to permit this extended operating interval. The NRC staff is currently reviewing your proposed amendment to change the existing Millstone Unit 3 TS in accordance with Generic Letter (GL) 91-04,

" Changes in Technical Specifications Surveillance Intervals to Accommodate a 24-Month Fuel Cycle." Based on the review completed to date, the staff has identified several inconsistencies between the proposed amendment request and the guidance in GL 91-04 that require additional technical justification as set forth in the Enclosure.

Sincerely *

(Original Signed By)

Vernon L. Rooney, Senior Project Manager Northeast Utilities Project Directorate Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket No: 50-423

Enclosure:

Request for Additional Information cc w/ encl: See next page

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T. Feigenbaum Millstone Nuclear Power Northeast Utilities Service Company Station Unit 3 cc:

Lillian M. Cuoco, Esq. M. H. Brothers, Nuclear Unit Director Senior Nuclear Counsel Millstone Unit No. 3 Northeast Utilities Service Company Northeast Nuclear Energy Company P.O. Box 270 P.O. Box 128 Hartford, CT 06141-0270 Waterford, CT 06385 Mr. Kevin T. A. McCarthy, Director Burlington' Electric Department ,

Monitoring and Radiation Division c/o Robert E. Fletcher, Esq. '

Department of Environmental Protection 271 South Union Street l 79 Elm Street Burlington, VT 05402 l Hartford, CT 06106-5127 l Mr. M. R. Scully, Executive Director  !

Mr. Allan Johanson, Assistant Director Connecticut Municipal Electric i Office of Policy and Management Energy Cooperative J Policy Development and Planning Division 30 Stott Avenue j 80 Washington Street Norwich, CT 06360

' Hartford, CT 06106 ,

Mr. William D. Meinert Mr. S. E. Scace, Vice President Nuclear Engineer Nuclear Reengineering Implementation Massachusetts Municipal Wholesale. ,

Northeast Utilities Service Company Electric Company P.O. Box 128 P.O. Box 426 l Waterford, CT 06385 Ludlow, MA 01056  ;

Regional Administrator Mr. E. A. DeBarba l Region I Vice President - Nuclear Technical j U.S. Nuclear Regulatory Commission Services  ;

475 Allendale Road Northeast Utilities Service Company l King of Prussia, PA 19406 P.O. Box 128 i Waterford, CT 06385 '

First Selectmen Town of Waterford Hall of Records 200 Boston Post Road Waterford, CT 06385 Mr. P. D. Swetland, Resident Inspector Millstone Nuclear Power Station c/o U.S. Nuclear Regulatory Commission P.O. Box 513 Niantic, CT 06357 Mr. D. B. Miller, Jr.

Senior Vice President Nuclear Safety and Oversight Northeast Utilities Service Company P.O. Box 270 Waterford, CT 06141-0270 l

._ - . . . . . - ._ . ~ . _ - . - - - - - . . .. . .- .- .-. . . - - .

! Mr. F. C. Rothen

! Vice President - Nuclear Work Services Northeast Utilities Service Company i

P.O. Box 128 Waterford, CT 06385 Mr. Ernest C. Hadley, Esq. .

1040 B Main Street l P.O. Box 549

West Wareham, MA 02576 i

!. Mr. John Buckingham i Department of Public Utility Control i Electric Unit i

10 Liberty Square New Britain, CT 06051 Mr. James S. Robinson ,

i Manager, Nuclear Investments and Administration New England Power Company

, 25 Research Drive

Westborough, MA 01582 1

Mr. B. D. Kenyon

President - Nuclear Group Northeast Utilities Service Company

P.O. Box 128 Waterford, CT 06385

)-

4

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RE00EST FOR ADDITIONAL INFORMATION MILLSTONE NUCLEAR POWER STATION. UNIT 3 24-MONTH FUEL CYCLE AMENDMENT DOCKET NO. 50-423 The NRC staff is currently reviewing a proposal by the Northeast Nuclear Energy Company (the licensee) to change the Technical Specifications (TS) for the Millstone Nuclear Power Station, Unit 3, to allow for a 24-month fuel cycle. The licensee submitted a request to change the surveillance interval for steam generator tube inspections by letter dated May 1, 1995. The NRC staff requires additional information to continue the review of the proposed amendment. Please provide a response to the staff's comments given below.

1. According to the guidance in Generic Letter (GL) 91-04, an engineering assessment should be completed prior to operation beyond 24 months. This assessment should demonstrate that all steam generator tubes will retain adequate structural margins under normal, transient, and accident conditions until the end of the fuel cycle, or 30 months, which ever occurs first. The licensee's submittal includes a discussion of such an engineering assessment. However, the text is proposed to be included in the Bases section. This should be specified in the TS. In addition, the staff requests that the licensee commit to submit such assessments to the NRC after their completion. The staff also notes that the text of " Insert

'X'" in the submittal states, "with plant operation for up to 30 months."

GL 91-04 specifies that such an assessment should be performed before

" operation beyond 24 months of the previous steam generator tube inspection." Provide a basis for this proposed TS change.

2. GL 91-04 specifies that licensees should lower the plant TS limits on reactor coolant system leakage for operation beyond 24-months when the results of either of the two previous inspections were in the C-2 Category. Since the NRC issued GL 91-04, the staff has refined its position on primary-to-secondary leakage requirements. For example, plants which employ the voltage-based tube repair criteria of Generic Letter 95-05, " Voltage-Based Repair Criteria for Westinghouse Steam Generatcr Tubes Affected By Outside Diameter Stress Corrosion Cracking,"

primary-to-secondary leakage is limited to 150 gallons-per-day (gpd) through each steam generator. The NRC staff believes that plants desiring to allow for operation beyond 24 months from the previous tube inspections should incorporate the primary-to-secondary leakage requirements as given in GL 95-05. These leakage restrictions would be in effect during the entire operating cycle and not only for operation beyond 24 months. The proposed amendment to extend the steam generator tube inspection period to accommodate a 24 month fuel cycle does not address a reduction in primary-to-secondary leakage. Please discuss the basis for not addressing a reduction in the TS leakage requirements.

3. The proposed changes to the Millstone Unit 3 TS are stated to be in accordance with GL 91-04. The NRC has identified several deviations between the proposed changes to the inspection frequencies and the guidance provided in GL 91-04. The following summarizes these apparent 1

Enclosure

deviations. In addition, the NRC staff has developed Table 1, similar to proposed Table 4.4-2a, outlining the inspection guidance in the GL. For each of the items discussed below provide a basis for the proposed TS changes. The NRC staff position on the deviations listed below is highlighted in Table 1.

a. Proposed Table 4.4-2a specifies a 50-month maximum inspection interval when the inspection category is C-1 for two consecutive inspections.

Proposed TS 4.4.5.3.b. and GL 91-04 specify that TS 4.0.2 allowing an extension to inservice inspection frequency does not apply to the steam generator tube inspection frequencies. Therefore, the maximum allowable interval between inspections is limited to 40 months.

b. If either the current or the previous inspection categories are C-3, then the maximum inspection interval is limited to 24 months.

However, if the plant was inspecting on a 40-month interval prior to the C-3 classification, the maximum interval is limited to 20 months in the period immediately following the C-3 inspections.

c. When the final tube inspection sampM includes at least 40 percent of the tubes and the results are C-2, then a 30-month interval is )

permitted only if the prior inspection results were not in the C-3 Category.

TABLE 1: STEAM GENERATOR TUBE INSPECTION FREQUENCIES Final Current Previous Inspection Interval Sample Inspection Inspection (months) Notes Size Category Category Minimum Maximum

< 20% C-1 C-1 12 40 C-1 C-2/3 12 24 C-2 C-1/2/3 12 24 20-40% C-1 C-1 12 40 i C-1 C-2 12 30 1 l C-2 C-1/2 12 30 1 C-1/2 Ca3 12 24

> 40% C-1 C-1 12 40 <

C-2 C-1/2 12 '0 3 1 C-1/2 G3 12 24 093 C:s 12 24 2 C;3 C-1,C-1,... 12 20 Notes:

(1) Assessment of structural and leakage integrity required for operation beyond 24 months.

(2) If a 40-month inspection irterval was not previously in effect.