ML17311B123
| ML17311B123 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 08/22/1995 |
| From: | Brian Holian NRC (Affiliation Not Assigned) |
| To: | NRC (Affiliation Not Assigned) |
| References | |
| TAC-M86178, TAC-M87744, TAC-M87820, NUDOCS 9508250273 | |
| Download: ML17311B123 (6) | |
Text
~~00 Wp0 Cy O
Cy V/4~
~O
++*++
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055&4001 August 22, 1995 5o- /28/$Zf +7@
LICENSEE:
Arizona Public Service Company FACILITY:
Palo Verde Nuclear Generating Station, Unit Nos.
1, 2, and 3
SUBJECT:
SUMMARY
OF MEETING HELD ON JULY 12,
- 1995, TO DISCUSS STEAM GENERATOR ISSUES (TAC NOS.
- M87744, M86178, AND M87820)
On July 12, 1995, the NRC staff met with representatives of Arizona Public Service Company (APS) to discuss steam generator eddy current inspection results, particularly relating to the issue of an appropriate cycle length for Palo Verde Unit 3.
Persons attending the meeting are listed in Attachment l.
Attachment 2 summarizes the recent Unit operating cycles.
The viewgraphs distributed at the meeting are in Attachment 3.
Since there have been four steam generator inspection outages in the last year, the licensee gave a brief history of outages and eddy current results.
The licensee discussed its program for managing tube degradation, highlighting improvements in defect detection, growth rate prediction, and leak rate analysis.
Much of the material had previously been submitted to the staff in the Unit 3 report, dated May 19, 1995.
Unit 3 had oper ated approximately 5 months before its last midcycle outage.
That outage ended December 19, 1994.
The licensee has proposed operating Unit 3 for up to ll months before the next steam generator tube inspection.
This inspection would then correspond with the fall refueling outage (currently scheduled to begin October 14, 1995).
The licensee performed an analysis to ensur e that the margins specified in Regulatory Guide (RG) 1. 121, "Bases for Plugging Degraded PWR Steam Generator Tubes,"
are maintained for the proposed operating time.
The analysis was similar to previous
- analyses, except that a specific Unit 3 crack growth rate model and specific distributions for material properties and crack length were employed.
Additionally, following a staff suggestion at a meeting in August 1994, the licensee benchmarked the model against actual Unit 3 inspection results.
The licensee calculated the probability of exceeding RG 1. 121 and the probability of tube rupture during a main steamline break and determined that a run time of 11 months was acceptable.
The licensee's calculations indicated that the probability of exceeding RG 1. 121 was 0.017 and of a tube rupture under main steamline break conditions was 0.001.
Additionally, APS had an independent RG 1. 121 assessment performed based on the inspection data for all three units.
This assessment was an alternative calculation of end-of-cycle conditions.
The results compared favorably with the primary model.
A leak rate model was also developed for free span axial cracks under faulted conditions to verify that the probability of exceeding 10 CFR Part 100 limits for maximum leakage during a main steamline break scenario is very. low.
'7508250273 950822 PDR ADQCK 05000528 8
~4'%K P<<
August 22, 1995 The staff's questions throughout the licensee's presentations focussed primarily on verifying that conservative assumptions were used.
The marked improvement in the licensee's experience and steam generator management philosophy since the 1993 steam generator tube rupture (SGTR) event was also discussed.
The licensee's eddy current testing program is comprehensive and its analyses are routinely independently verified.
Since the SGTR, it has had approximately 4.7 reactor-years of operation with restrictive administrative leak limits and no significant leakage.
Although the staff did not review the licensee's probabilistic methodology in detail, the staff accepted the licensee's conclusion that operating Unit 3 until the October refueling outage before doing the next steam generator eddy current inspection is supportable given the limited number and size of indications detected at Unit 3 during the past inspection.
The staff also questioned the licensee about the analysis of the Unit 2 steam generator eddy current data.
Unit 2 has historically shown the most tube degradation.
Unit 2 was started up from its last refueling outage in April 1995.
It has a 12-month core to return the unit to the appropriate outage cycle.
The licensee stated that it is still evaluating the eddy current data and is attempting to use phase angle data to better quantify crack depths.
It expects to submit a Unit 2 report in August 1995.
The staff will discuss Unit 2 cycle length with the licensee after reviewing that report.
This summary completes the work under TAC Nos.
- M87744, H86178, and H87820.
New individual unit TAC numbers will be opened, as necessary, to review future licensee submittals on steam generator tube integrity.
priginal Signed By games W.. Clifford for Brian E.
Hol i an, Sen> or rroject Manager Project Directorate IV-2 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket Nos.
50-528, 50-529, and 50-530 Attachments:
1.
Meeting Attendees 2.
Palo Verde Operating Cycles 3.
Licensee Viewgraphs cc w/atts:
See next page DISTRIBUTION w Atts 1
2 and 3:
(Docket Filets PUBLIC PDIV-2 Reading J. Dyer, RIV B. Holian K. Karwoski C.
Thomas
~A W. Russell/F. Hiraglia W. Bateman E. Jordan, T-4D118 NRC Participants DOCUMENT NAME:
PV71295.HTS R.
Zimmerman E.
Adensam E. Peyton OGC ACRS (4)
J. Mitchell, EDO J.
Roe
- For revious concurrences see attached ORC OFC NAME DATE PDIV-2 E ey on 8
95 PDI BHolian: k 8
5 EMCB*
TSullivan 8 21 95 OFFICIAL RECORD COPY
- r. \\
August 22, 1995 cc w/encls:
Mr. Steve Olea Arizona Corporation Commission 1200 W. Washington Street
- Phoenix, Arizona 85007 T.
E. Oubre, Esq.
Southern California Edison Company P. 0.
Box 800
- Rosemead, California 91770 Senior Resident Inspector USNRC P. 0.
Box 40
- Buckeye, Arizona 85326 Regional Administrator, Region IV
,U. S. Nuclear Regulatory Commission Harris Tower
& Pavillion 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064
- Chairman, Board of Supervisors ATTN:
Chairman 301 W. Jefferson, 10th Floor
- Phoenix, Arizona 85003 Mr. Aubrey V. Godwin, Director Arizona Radiation Regulatory Agency 4814 South 40 Street
- Phoenix, Arizona 85040 Mr. Curtis Hoskins Executive Vice President and Chief Operating Officer Palo Verde Services, 2025 N. 3rd Street, Suite 200 Phoenix, Arizona 85004 Roy P.
Lessey, Jr.,
Esq.
Akin, Gump, Strauss, Hauer and Feld El Paso Electric Company 1333 New Hampshire Avenue, Suite 400 Washington, DC 20036 Ms. Angela K. Krainik, Manager Nuclear Licensing Arizona Public Service Company P.O.
Box 52034
- Phoenix, Arizona 85072-2034 Mr. William L. Stewart Executive Vice President, Nuclear Arizona Public Service Company Post Office Box 53999
- Phoenix, Arizona 85072-3999
Attachment I MEETING WITH ARIZONA PUBLIC SERVICE PA 0 VERDE - ST AM G N
RATOR ISSUES T
ENDANCE LIST JULY 12 1995 rizona Public Service Rick Schalk Russ Cipolla Ed Fernendez Joseph R. Provasoli Douglas Hansen Kevin Sweeney gRC Brian Holian Ted Sullivan Ken Karwocki Phillip Rush Emmett Hurphy Steve Long Charles Thomas Eileen HcKenna Packer En ineerin
/
Jim Begley Brian Woodman STS Lynn Connor
\\
l~