ML20059K433
| ML20059K433 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 09/13/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20059K431 | List: |
| References | |
| NUDOCS 9009210297 | |
| Download: ML20059K433 (4) | |
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k UNITED STATES
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' NUCLEAR REGULATORY COMMISSION.
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WASHINGTON, D. C. 20005 -
1 SAFETY EVALUATION.BY.THE.0FFICE OF NUCLEAR.REATOR REGULATION INTERGRANULAR. STRESS-CORROSION. CRACKING. INSPECTION AND. REPAIR EVALUATION.
JAMES A. FITZPATRICK RELOAD 8/ CYCLE.9 REFUEL OUTAGE POWER. AUTHORITY.0F THE. STATE.0F NEW. YORK JAMES A. FITZPATRICK NUCLEAR. POWER. PLANT DOCKET.NO. 50-333 1.0 INTRODUTION i
By letters dated November 10,1988(JPN-88-061'andJPN-88-062), March 24,1989 (JPN-89-012) and ' January 29 1990 (JPN-90-012), the Power Authority of the StateofNewYork(licensee}submittedtheresultsofinspectionsandrepairs performed during the James A.-FitzPatrick's Reload 8/ Cycle 9 Refueling Outage.
The licensee inspected one creviced safe' end and 92 welds that included 54
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welds of the original inspection sample and an expanded sample of 38 welds-because flaws were detected in the original sample. A review of Induction HeatingStressImprovement(IHSI) process;recordsfor? flaws'reportedin1988 was also conducted. By -letter dated August 19,1988 (JPN-88-043), the licensee submitted results of laboratory testing and analytical evaluation to'su theapplicationofresistanceheatingstressimprovementprocess.(RHSI)pport as an acceptable IGSCC mitigation. -The RHSI process was_ applied to two recirculation' welds during 1987.efueling outage.
2.0 DISCUSSION The staff reviewed the licensee's IGSCC inspection and' repair results for the Reload'8/ Cycle 9 Refuel Outrage.- The licensee initially identified nine welds with new IGSCC indications.. After further evaluation, the licensee concluded thattheindicationsidentifiedinoneoftheninewelds(No.28-37)wasnot due to IGSCC.
In the 1988 outage,' weld overlays were' applied to nine welds of which,seven were new IGSCC findings and two were previously detected indications.
The overlays were designed to either the standard overlay or designed overlay in accordance with NUREG-0313, Revision 2.
In' addition,twowelds(Nos.12 and 28-56) which had previous IGSCC indications noted, were inspected and found'not to contain IGSCC. Also,fourwelds>(Nos.28-112, 28-33,'12-4, and L
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28-53)'were evaluated by fracture mechanics to be acceptable without overlay.
repair. However, the licensee will reinspect welds 28-33 and 28-112 during the mid-cycle outage (September 1989) to ensure there is no excessive crack growth.
.The nine safe-end to nozzle welds containing Income;182 butter and three Residual Heat Removel (RHR) system. bimetallic welds were inspected ud did not-have any indications of IGSCC.
The licensee requested relief from certain NUREG-0313, Rev. 2, technical recommendations as follows:
a 1.
The licensee requested relief from the inspection recommendations of NUREG-0313, Rev. 2, paragraphs 5.3.1.5 & 6 and 5.3.2.5 8.6 for two- '
standard and one designed weld overlays installed on the Core Spray "B" loop during the 1987-refueling outage.
The licensee requested that the NRC allow operation for more than one fuel cycle (November 7, 1988 thru.
September 1989) with the overlays presently installed. The-piping is-scheduled to be replaced during the 1989 maintenance outage and surface-finishing anil inspection in this outage would not be keeping with the As-Low-As-Reasonably-Achievable (ALARA) criteria (estimated 8 person-rem).*
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2.
The licensee requested relief be granted so that only three welds-on one RHR loop instead of six welds on two loops would be inspected during the 1988 refueling outage.
If IGSCC is detected in one of the welds, the other three welds will be inspected. The-licensee's relief is requested because of the high radiation levels and because of the ALARA saving (estimated to be 12.5 person-rem). The three uninspected welds will be inspected during the next schedu bd refueling outage in 1990.
3.
The ' licensee requested relief from the recomendations of NUREG-0313, Rev. 2, paragraph 5.3.2.7, to inspect all IGSCC Category G Weldments (four welds) in the Recirculation System. The' licensee proposed to
, inspect two of the four welds due to ALARA consideration of ar. estimated.
three person-rem to inspect the.two additional welds. The two remaining welds will be inspected during the next scheduled refueling outage and, if IGSCC is detected in one of these welds,1the additional two welds will be inspected during that refueling outage.
The staff concludes that the above exceptions-from NUREG-0313, Revis " % for the IGSCC inspection in this refueling outage are acceptable.
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- Subsequently, by letter dated September 29 1989 WPN-89-063), the licensee described operational problems and inspection results as justification for cancelling plans to replace this piping during the 1989 maintenance outage.
The weld overlays were surface finished and inspected, however, during the maintenance outage with no defects noted.
i By letter dated May 25, 1990~
(JPN-90-41), the licensee informed the NRC of plans to replace the piping during the 1991 refueling outage. The staff has found this to be acceptable.
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we During this outage
. Independent Testing, Labs (P-Scan),.and sizing w
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two inspectors from EBASCO, PASNY and General El and-
-an NRC Region I inspector selectively reviewed the ultras e
procedures and data In addition, non-destructive exam,inations performed during this re examination d
L inspector concluded, in hic Inspection Report No
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ng outage. The NRC 1988, that nondestructive examinations were performed b
. 55-333/88-26
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and that no violations of NRC requirements were identified dated October 28, y qualified personnel The licensee performed 'an Induction Heating Stree Imp review and found that IHSI was performed in the fall of 1984ro weld (No.12-15) which was treated in the spring of 1984
, except for one records confirm that the minimum EPRI criteria for e
.The treatment each of the evaluated welds which was recorded to be.les,s than the minimum acceptab with the exception when a-single thermocou c
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cases.
The effects of the low readings were ev IHSI vender.
emperature onia;few 28-inch wel:Is associated with heavy components (val in treatment of these configurations has involved offs t were the valve or pump veor. pump).
IHSI practice.
combination of the, component and pipe wall'thicknessbe away from e of the coil zone may-have affected the post treatment residual stress d Thus, the flawed locations.
stribution at'the During the 1987 refueling outage the licensee ap li d stress improvement (RHSI) process on two 28-inch recirc l (28-02-50and28-02-2-108) p e for IGSCC mitigation under pipe whip restraints and ua on piping welds j
and is applying for a patent for its' applicationa 1
process was demonstrated by performing destru
.. The effectiveness of this ona28-inchtestpipe(Schedule 80 t
ual stress me heat treatment coils that were subsequently used i
after FitzPatrick plant. Southwest Research'Institu n two field weldstrameters 'and L
residual stress measureme at the measured by strain gages (nts for the licensee.te (SWRI) performed the? destrui The residual stressesLwere using the parting out and layers r)emoval-technique rosette mounted on the surfaces of the test: pipe found to be compressive an the inside: surface of th The rasidual stresses were compressive about half way through the pipe wall thicknesse te Integrity Associatesstresses on the.outside' surface of the test sipe were-tensile
. The residualL.
stresses evaluated by the finite element str
. The'Structurali--
ing the Welds 11 program for the ~1icensee L
determined destructively.
The residual covered by the resistance heating coil.in the licensee's To ensure the process is reliable an e
effective variation., additional process control is needed to reduce th l
mitigating IGSCC should also be considered.-Furthermore c veness-in-
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4-Based on cur review of the licensee's'submittals on the application of the RHSI l process, we conclude that.the two recirculation welds-(28-02-2-50 and 29-02-2-108) treated with the RHSI process _are acceptable as Category C welds because it has been demonstrated experimentally and analytically that the RHS! process used in the subject treatment will generate compressive residual stresses in the inner portion of the pipe wall. However, because of very limited testing and field experience of RHSI treated piping, the staff recommends that the application of the RHSI process should be limited to conditions where other stress improvement processes (IHSI and MSIP), recommended in NUREG 0313, Revision 2, cannot be applied.-
The staff wil.1 review each application oil a case-by-case basis and the effectiveness' of the application should be demonstrated both experimentally and analytically.
3.0 CONCLUSION
The staff has evaluated the licensee's IGSCC inspections and repairs performed during FitzPatrick's Reload 8/ Cycle 9 Refueling Outage. The staff concludes that these activities were performed in accordance with the guidelines in-NUREG-0313, Revision 2, and are acceptable.
In addition the staff also concludes that the FitzPatrick Nudlear Power Plant can safely opera,te for an 18-month fuel cycle in the present configuration provided the mid-cycle inspection of welds 28-33 and 28-112 does not show; t
excessive crack growth.
Dated:
September 13, 1990 Principal. Contributor:
L W. Koo l
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