ML20216D813

Forwards Request for Addl Info Re SG Tube End Cracking Alternate Repair Criteria for Plant,Unit 1

ML20216D813
Person / Time
Site:	Arkansas Nuclear
Issue date:	07/28/1999
From:	Nick Hilton NRC (Affiliation Not Assigned)
To:	Hutchinson C ENTERGY OPERATIONS, INC.
References
TAC-MA5557, NUDOCS 9907300137
Download: ML20216D813 (5)

Text

q o '..

July 28,1999 Mr. C. Randy Hutchinson Vice President, Operations ANO Entergy Operations, Inc.

1448 S. R. 333 i

Russellville, AR 72801

SUBJECT:

ARKANSAS NUCLEAR ONE, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION - STEAM GENERATOR TUBE END CRACKING ALTERNATE REPAIR CRITERIA (TAC NO. MA5557)

Dear Mr. Hutchinson:

In a letter dated June 1,1999, Entergy Operations, Inc. (EOI), submitted a request for an amendment to the Arkansas Nuclear One, Unit 1 (ANO-1) operating license. The request proposed an alternate repair criteria for axial tube end crack indications in the ANO-1 steam generators. In order to complete our review of this request, we require additional information as specified in the enclosure to this letter.

This request for additional information was discussed with Mr. John Dosa, and others of your staff on July 20,1999. On July 21,1999, Mr. Dosa and I agreed to a response date of approximately 45 days frcim the date of receipt of this letter. We agreed the extent of response had not been determined yet and could, therefore. affect your response date. However, we also agreed that for this request to support your upcoming outage, a timely reply is required.

Sincerely,

/S/

Nicholas D. Hilton, Project Manager, Section 1 Project Directorate IV & Decommissioning 9907300137 990728 Division of Licensing Prt, ject Management DR ADOCK 05 33 Office of Nuclear Reactor Regulation Docket No. 50-313

Enclosure:

As stated cc w/ encl: See next page kh et F e PUBLIC i

PD#1V-1 Reading l

f S. Black S. Richards f

J.Tsao l

l OGC ACRS K. Brock' man, RIV e0 i To receive a copy of this document, indicate "C" in the bcgrs j

OFFICE PDIV-1/PM C/ PDIV-1/LM ( PDIV-hk, p' -

NAME NHilton:db 7 LBerry, h9

)

RGramm V

DATE 1 /# /99

'l /k/99 1 /9N99 DOCUMENT NAME: G:\\PDIV-T\\ANO1\\raia5557.wpd FHCIAL RECORD COPY l

300050

[

r

.pp u:oq 8

k UNITED STATES 5

[

j NUCLEAR REGULATORY COMMISSION f

WASHINGTON. D.C. 20066 4001 s*****/

July 28, 1999 i

Mr. C. Randy Hutchinson Vice President, Operations ANO Entergy Operations, Inc.

1448 S. R. 333 Russellville. AR 72801 l

SUBJECT:

ARKANSAS NUCLEAR ONE, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION - STEAM GENERATOR TUBE END CRACKING ALTERNATE REPAIR CRITERIA (TAC NO. MA5557)

Dear Mr. Hutchinson:

J In a letter dated June 1,1999, Entergy Operations, Inc. (EOl), submitted a request for an

)

amendment to the Arkansas Nuclear One, Unit 1 (ANO-1) operating license. The request proposed an alternate repair criteria for axial tube end crack indications in the ANO-1 steam generators. In order to complete our review of this request, we require additionalinformation as specified in the enclosure to this letter.

This request for additionalinformation was discussed with Mr. John Dosa, and others of your staff on July 20,1999. On July 21,1999, Mr. Dosa and I agreed to a response date of approximately 45 days from the date of receipt of this letter. We agreed the extent of response had not been determined yet and could, therefore, affect your response date. However, we also agreed that for this request to support your upcoming outage, a timely reply is required.

Sincerel,

Y Nicholas D. Hilton, Project Manager, Section 1 Project Directorate IV & Decommissioning Division of Licensing Project Managernent Office of Nuclear Rec ;or Regulation Docket No. 50-313

Enclosure:

As stated cc vdencl: See next page Iram'

p l\\

l Arkansas Nuclear One cc:

Executive Vice President Vice President Operations Support

& Chief Operating Officer Entergy Operations, Inc.

Entergy Operations, Inc.

P. O. Box 31995 P. O. Box 31995 Jackson, MS 39286-1995

- Jackson, MS 39286-1995 i

Wise, Carter, Child & Caraway Director, Division of Radiation P. O. Box 651 Control and Emergency Management Jackson, MS 39205 Arkansas Department of Health 4815 West Markham Street, Slot 30 Little Rock, AR 72205-3867 Winston & Strawn 1400 L Street, N.W.

Washington, DC 20005-3502 Manager, Rockville Nuclear Licensing Framatone Technologies 1700 Rockville Pike, Suite 525 Rockville, MD 20852 Senior Resident inspector U.S. Nuclear Regulatory Commission P. O. Box 310 London, AR 72847 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 County Judge of Pope County Pope County Courthouse Russellville, AR 72801 I

May 1999

r q

REQUEST FOR ADDITIONAL INFORMATION ARKANSAS NUCLEAR ONE. UNIT 1 STEAM GENERATOR TUBING ALTERNATE REPAIR CRITERIA FOR AXlAL TUBE END CRACKS in a letter dated June 1,1999, Entergy submitted for staff review an amendment request to revise Arkansas Nuclear One, Unit 1 (ANO-1), Technical Specifications (TSs). The proposed amendment is to implement alternate repair criteria for axial tube end crack (TEC) indications in the upper and lower tubesheets of ANO-1 steam generators. The alternate repair criteria would allow tubes having axially oriented TEC indications located within the clad region of the tubesheet to remain in service. In order to continue its review, the staff requests the following additional information. Questions related to the topical report, BAW 2346P, are the same as those that were forwarded to Florida Power Corporation, which has proposed the same alternate repair criteria for the Crystal River nuclear plant.

Questions on the June 1.1999. letter 1.

Proposed TS 4.18.3.a.4 states that tube ends with axial TEC indications will be inspected using a rotating coil during all subsequent inspections. In order to understand the planned inspection scope variations and the intended indication characterization, please address the following questions.

a.

During subsequent inspections, what inspection scope would be used for the tube ends without previously identified axial TEC indications?

i b.

If new TEC indications are detected in tube ends that were not identified in previous inspections, how would the new axial TEC indications be accounted for in the C-1, C-2, and C-3 categories?

c.

If the plant is shut down due to steam generator tube leakage, and the leakage source is determined to be from a TEC indication (s) in one steam generator, what inspection scope, with associated expansions, is planned for both the affected steam generator and the unaffected steam generator (similar to other requirements in TS 4.18.4.c.1)?

2.

In proposed TS 4.18.6, the proposed changes included changing the reporting period requirement from 45 days to 90 days, and including a summary of the condition i

monitoring and operational assessment results for TEC indications. What reporting mechansim will be used if the operational assessment concludes that the potential leakage exceeds the leakage limit under the main steamline break condition?

Changes to the proposed ANO-1 TSs may be necessary to address the preceding points.

Enclosure

C

]

)

2 Questions on t3AW-2346P. April 1999 3.

TEC Growth Assessment (pages 79-83) a.

Page 80 states that a positive number in Figures 9-3 and 9-4 represents apparent crack growth. Explain the negative growth values in those figures and the causes for the negative growth values.

b.

Were negative growth rates used in calculating the mean growth rate, and if so, what is the basis for using negative values?

c.

Framatome calculated an average growth rate of 0.01 inch per effective full-power year for steam generator "A". However, the maximum growth rate in the growth data is 0.06 inch as shown in Figure 9-3. What is the basis for not using a bounding growth rate?

d.

If the average growth rate is found to be positive, Entergy needs to assess the impact of the growth rate distribution on the alternate repair criteria methodology.

Please provide appropriate reporting requirements in the proposed TS for such assessments.

4.

Page 84 states that the probability of detection (POD) for plus-point and for pancake coil probes were derived based on a 90 percent confidence for cracks greater than 50 percent through-wall. What is the basis for using a 90 percent confidence value for cracks greater than 50 percent through-wall?

5.

The leakage from TEC indications was calculated by Entergy based on applying a 50 percent probability with 95 percent confidence (60/95) leak rate for each TEC indication and then summing these leak rates to obtain the total steam generator leak rate. These leak rates have been adjusted to reflect a POD of 0.84 evaluated at a 90 percent confidence level. Piene submit information assessing the conservatism of the described estin! ate relative to a total steam generator leak rate, POD adjusted, which is conservative with a probability of 0.95 when evaluated at the 95 percent confidence level (95/95).

4 1

1 l