JPN-88-010, Forwards Proprietary NEDC-30799-P, Feedwater Nozzle Fracture Mechanics Analysis to Show Compliance W/ NUREG-0619, & Description of Proposed Insp Program for Feedwater Nozzles & Discussion of Program Justification
| ML20148H516 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 03/25/1988 |
| From: | Brons J POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-NUREG-0619, RTR-NUREG-619 JPN-88-010, JPN-88-10, NUDOCS 8803300015 | |
| Download: ML20148H516 (9) | |
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' 123 fjain Street White Plains. New York 10601 914 CSI 6240
- > NewWrkPower th"c=;r,_,
tv Authonty u ~ ~-o March 25, 1988 JPN-88-010 U.
S.
Nuclear Regulatory Commission Attn:
Document Control Desk Washington, D.C.
20555
Subject:
James A. FitzPatrick Nuclear Power Plant Docket No. 50-333 NUREG-0619 - Feedwater Nozzle Inspections
References:
- 1. PASNY letter, J.
P.
Bayne to D.
- Eisenhut, February 20, 1981 (JPN-81-12).
- 2. NUREG-0619, "BWR Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking," November 1980.
3.
NYPA letter, J.
C.
Brons to D.
B.
Vaasallo, August 20, 1985 (JPN-85-65).
Dear Sits:
As discussed in Reference 1, the Authority currently inspects FitzPatrick feedwatar nozzles in accordance with Reference 2.
However, based on the results of previous i ns pec t i.o n s, and because of radiological concerns, the Authority has decided to reduce the inspection frequency. describes the proposed inspection program and discusses its justification., NEDC-30799-P, is a plant specific fracture mechanics assessment of the FitzPatrick feeduater nozzle.
This report was prepared by General Electric and originally submitted in Reference 3.
It is included for your convenience.
This report contains information which the General Electric Company customarily maintains in confidence and withholds from public disclosure.
The information has been handled and classified as proprietary to General Electric as indicated in the attached affidavit (Attachment 3). We request that NEDC-30799-P be withheld from public disclosure in accordance with the provisions of 10 CFR 2.790.
NRC review of the proposed program and response prior to the 1988 refueling outage, which is scheduled to begin August 28, 1988, is requested.
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i Should you or your staff have any questions regarding this matter, please contact Mr.
J.
A.
Gray, Jr. of my staff.
Very truly yours,
-[ohn C.
Brons xecutive Vice President luclear Generation cc:
Office of the Resident Inspector U.
S.
Nuclear Regulatory Commission P.
O.
Box 136 Lycoming, New York 13093 U.
S.
Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Mr. Harvey Abelson Project Directorate I-l Division of Reactor Projects - I/II U.S.
Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852 l
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JPrl-88 -010 ATTACHMENT I
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l tiew York Power Authority James A.
FitzPatrick tiuclear Power Plant Docket tio. 50-333 l
FUREG-0619, PEEDUATER N0ZZLE CRACKING Introduction Between 1974 and 1980, inspections disclosed cracking in the bores and inner radii of feedwater (FW) nozzles in 18 of the 23 operating United States boiling water reactors (BURS).
Following a review the NRC staff documented their recommendations in NUREG-0619 (Attachment Reference 1) anti Generic Letter (GL) 81-11 (Attachment Reference 2).
In Referente 1 the Staff concluded that the cracks were initiated by high-cycle thermal fatigue resulting from turbulent mixing of cold I'W bypass leakage with hot reactor recirculation water.
Attachment Reference 1 required operating BWRs to remove stainless steel cladding from FW nozzles, modify FW spargers, install new low flow controllers, reroute the Reactor Water Clean Up (RUCU) system return flow to all FW lines, modify the control rod drive return line, and conform to a specific inspection interval.
- 3L 81-11 later stated that continued use of the existing controller ()r a controller modified to meet the basis of NUREG-0619) would be acceptable, if a plant specific fracture mechanics analysis showed that existing cracks in FW nozzles would not grow to more than one inch in 40 years.
The FitzPatrick plant has complied with Attachment Reference 1 by removing stainless steel cladding, installing double piston ring triple - thermal - sleeve spargers, cutting and capping the control rod drive return lines, changing the internal valve trim in the low flow feedwater control valve, and nodifying the inspection program.
The Authority demonstrated by plant specific analysis (Attachment 2) that, with the amplitude and number of thermal transients (startup, shutdown, and scram) expected to occur during the 40 year life of the FitzPatrick plant, existing cracks in FW nozzles kill not grow to more than one inch in 40 years.
The Authority alsc demonstrated that rerouting the RWCU system wculd not decrease the fatigue usage factor significantly.
Therefore, the existing low-ficw controller and the RUCU system are acceptable per Attachment Reference 1 without further modification.
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4 Inspection History As outlined in Attachment Reference 3, the FitzPatrick plant originally had a FW sparger with a considerably tighter fit than those in plants which experienced severe cracking.
Early published data on FW nozzle cracking indicates that plants with tight fit spargers are less susceptible to cracking.
In 1978, the Authority inspected and modified the FW nozzles (removed the cladding) and installed the new tight fit spargers at the FitzPatrick plant.
The Authority found no crack indications at anytime before or during modification.
Since then, the Authority has been performing inspections in accordance with Table 2 of NUREG-0619 (Attachment Reference 1).
NUREG-0619 requires routine inspection of the FW nozzle safe-end, bore, and inner radius.
For the FitzPatrick plant, NUREG-0619 requires an external ultrasonic test (UT) of all FW nozzle safe-ends, bores, and inside radii every two refueling cycles.
It also requires a visual inspection every four refueling cycles and a liquid penetrant test every nine refueling cycles.
The Authority performed external UT inspections on all FW nozzle bores and inner radii during refueling outages in January 1982 and again in April 1985.
The Authority performed a remote visual inspection on spargers in March 1985 and bolt nozzle inner radii and spargers during the refueling outage in February 1987.
None of these inspections revealed reportable indications.
During the inspections, many workers accumulated significant exposure.
Radiation fields in the area of the FU nozzles are approximately 250-800 mr/hr.
The cumulative radiation dose for FW nozzle inspection varies from 5 to 7 person-rem (including UT examiners and craft laborers).
Labor and material costs to the Authority range from $70,000 to $100,000 per inspection.
Considering the expense and high radiation dose and the fact that no reportable indications were found, the Authority plans to reduce the inspection frequency.
The Authority has reviewed existing UT techniques and FU nozzle inspection procedures.
Due to long paths and complex geometries, techniques available when FW nozzle cracking was discovered at other plants could not accurately locate and characterize cracks in the FW nozzle.
Today, improved techniques (angle beam shear wave) can reliably detect flaws before they exceed ASME Code allowable flaw size.
The Authority will follow developments in UT techniques and utilize the best available to perform future nozzle inspections. l
The NYPA nozzle inspection progran for the FitzPatrick plant conforms to the 1980 ASME Boiler and Pressure Vessel Code, including the 1981 Winter Addenda.
Specifically, the inspection program complies with Table IWB-2412-1, Inspection Program B, for the second 10 year inspection interval which began in 1985.
The planned feedwater nozzle inspections are incorporated in this program and will be conducted as follows:
e For the second 10 year interval, the Authority will perform an external UT on 50% of the FW nozzles, safe-ends, bores, and inner radii by 1992 and the remainder by the end of the interval.
a For the third 10 year interval beginning in 1995, the Authority will perform external UT of 50% of the FW nozzles within the first five years and the remainder by the end of the interval, e
Visual examination of nozzle inner radius and sparger will be performed during reactor vessel interior exanination as required by ASME Section XI, Code Category B13.10.
(Attachment Reference 4)
For each inspection, the results will be evaluated and dispositioned
- according to applicable governing codes.
Section 4.2 of NUREG-0619, states that implementation of the recommendations will assure long-term operation without significant crack growth.
It further states that the recommendations will permit an extension of time between inspections thus reducing radiation exposure.
Therefore, the Authority's planned inspection frequency complies with the requirements of Attachment Reference 1 and will not affect safety.
Attachment References 1)
NRC NUREG-0619, "BWR Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking," November 1980.
2)
G.
Eisenhut to All Power Reactor Licensees and License Applicants, February 20, 1981.
3)
NYPA Letter, G. T, Berry to R.
W.
Reid, dated June 21, 1977.
4)
"Rules for Inservice Inspection of Nuclear Power Plant Components", ASME Boiler and Pressure vessel Code,Section XI, 1980 Edition.
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4 JPN-88 010 ATTACHMENT II l
l New York Power Authority James A.
FitzPatrick Nuclear Power Plan Docket No. 50-333 l
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