ML20206Q082

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Summary of 860716 Meeting W/Util & GE Re Need for mid-cycle IGSCC Insp of Facility.List of Attendees Encl
ML20206Q082
Person / Time
Site: Brunswick Duke Energy icon.png
Issue date: 09/02/1986
From: Sylvester E
Office of Nuclear Reactor Regulation
To:
Office of Nuclear Reactor Regulation
References
NUDOCS 8609040044
Download: ML20206Q082 (5)


Text

September 2, 1986 Docket No. 50-324 w

LICENSEE: Carolina Power and Light Company (CP&L)

. FACILITY: Brunswick Steam Electric Plant, Unit 2 (BSEP 2)

SUBJECT:

SUMMARY

OF MEETING HELD ON JULY 16, 1986:

INTERGRANULAR STRESS CORR 0SION CRACKING

Background

Discussions were held with the CP&L staff and their contractor staff (General Electric Co.) regarding the need for a mid-cycle IGSCC inspection of Brunswick Steam Electric Plant, Unit 2 (BSEP 2). The list of attendees is provided as Enclosure 1.

By letter dated May 8, 1986, CP&L submitted a description of the inspection, repair and replacement of piping susceptible to IGSCC, performed during the BSEP 2 Reload 6 outage which began December 1, 1985 and ended June 11, 1986.

The IGSCC program included piping and welds in the recirculation system, the reactor water cleanup system, and the residual heat removal system.

By letter dated June 12, 1986, the NRC staff transmitted the results of our evaluation of the BSEP 2 IGSCC program to CP&L. Concerns were identified by the NRC staff relative to two unrepaired recirculation outlet nozzle-to-safe-end welds. Although the CP&L evaluation concluded that BSEP 2 could be safely operated for a full 18-month cycle with these unrepaired welds, the NRC staff recommended that a mid-cycle inspection of the suspect welds be performed. The following concerns were cited as the basis for the NRC position:

(1) Past experience with ultrasonic testing (UT) has shown that the detection and sizing of axial cracks by this method are not sufficiently accurate or reliable to support full-cycle operation. The cracks in the two unrepaired welds could be substantially deeper than reported. ,

(2) The crack growth evaluation for the unrepaired welds, performed by GE, was judged to be non-conservative in that GE's assumption of plateau crack growth behavior was based on limited test data for Inconel 182.

(3) The identified cracks in the Inconel 182 butter may extend into the reactor vessel nozzle during continued plant operation. This would be a more significant problem than weld cracking since it would constitute a degradation of the reactor vessel itself.

6609040044 e60902 PDR ADOCK 05000324 (D PDR

O Meeting Suninary The NRC letter of June 12, 1986 requested that CP&L respond with either a commitment to perform a mid-cycle inspection or provide justification to not perform the inspection. CP&L prepared a response, dated July 15, 1986, and requested a meeting with the NRC staff to discuss the contents of the response.

Presentations were made to the NRC staff by CP&L and GE personnel at the July 16, 1986 meeting. The three NRC concerns stated above were addressed to justify the CP&L position that BSEP 2 can be operated for a full 18-month operating cycle with no need for a shutdown for a mid-cycle IGSCC inspection.

The material presented by CP&L and GE is documented in the July 15, 1986 CP&L submittal. CP&L concluded the following:

(1) Concerns arising from past experience relative to the inaccuracy and unreliability of UT crack sizing do not apply to the Reload Outage 6 BSEP 2 IGSCC inspections. State-of-the-art methods were used to provide greater confidence in the crack size determinations.

(2) General Electric Co. data, as supplemented by data from other investigators, indicate that the crack growth rate used in the flawed pipe analysis is conservative. CP&L also concluded that the applied stresses used in the analyses were conservative.

(3) The cracks in the nozzle welds are not expected to grow significantly into the reactor vessel nozzle material which is low alloy steel and not susceptible to IGSCC. Any crack propagation into the nozzle would be due predominately to fatigue cycling. Cyclic stresses are very small for the recirculation outlet nozzles, and therefore crack growth into the nozzle would be insignificant.

The NRC staff received copies of the CP&L July 15, 1986 submittal documenting the CP&L arguments against the need for a mid-cycle inspection. This submittal and the material discussed at the meeting will be reviewed and an evaluation transmitted to CP&L by October 31, 1986.

O W netsMned W Ernest D. Sylvester, Project Manager BWR Project Directorate #2 Division of BWR Licensing

Enclosure:

As stated cc w/ enclosure:

See next page BWR 2 BWR#2 SN ris ESylvester;eh 9 /A/86 / /86

Enclosure Meeting Attendees NRC CP&L W. Hazelton L. Wheatley R. Johnson J. Titrington W. Koo C. Patterson R. Hermann B. Hinkley D. Muller R. Poulk E. Sylvester M. Turkal W. Collins General Electric Co.

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Mr. E. E. Utley .

Brunswick Steam Electric Plant Carolina Pcwer & Light Company Units I and 2 Cc: ,

Mr. P. W. Howe Mr. C. R. Dietz Vice President Plant General Manager Brunswick Nuclear Project Brunswick Nuclear Project Box 10429 Box 10429 Southport, North Carolina 28461 Southport, North Carolina 28461 Thomas A. Baxter, Esquire Mr. H. A. Cole Shaw, Pittman, Potts & Trowbridge Special Deputy Attorney General 1800 M Street, N. W. State of North Carolina Washington, D. C. 20036 P.O. Box 629 Raleigh, North Carolina 27602 Mr. D. E. Hollar Associate General Counsel Mr. Robert P. Gruber Carolina Power & Light Company Executive Director Post Office Box 1551 Public Staff - NCUC Raleigh, North Carolina 27602 P.O. Box 29520 Raleigh, North Carolina 27626-0520 Mr. Christopher Chappell, Chairman Board of Commissioners Post Office Box 249 Bolivia, North Carolina 28422 Mrs. Chrys Baggett State Clearinghouse Budget and Management 116 West Jones Street Raleigh, North Carolina 27603 Resident Inspector U. S. Nuclear Regulatory Commission Star Route 1 Post Office Box 208 Southport, North Carolina 28461 Regional-Administrator, Region II U. S. Nuclear Regulatory Commission 101 Marietta Street, Suite 2s00 Atlanta, Georgia 30303 Dayne H. Brown, Chief Radiation Protection Branch Division of Facility Services N. C. Department of Human Resources 701 Barbour Drive Raleigh, North Carolina 27603-2008

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s MEETING

SUMMARY

DISTRIBUTION Licensee: Carolina Power & Light Company

  • Copies also sent to those people on service (cc) list for subject plant (s).

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