ML17312B735
| ML17312B735 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 10/16/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17312B734 | List: |
| References | |
| NUDOCS 9710210235 | |
| Download: ML17312B735 (8) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON> D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE FIRST TEN-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN RE UEST FOR RELIEF NO.
10 ARIZONA PUBLIC SERVICE COMPANY PALO VERDE NUCLEAR GENERATING STATION UNIT NO.
1 DOCKET NO.
STN 50-528
1.0 INTRODUCTION
The Technical Specifications for Palo Verde Nuclear Generating Station (PVNGS), Unit 1. state that the inservice inspection of the American Society of Mechanical Engineers (ASME) Code Class 1,
2 and 3 components shall be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable addenda as required by 10 CFR 50.55a(g),
except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i).
Section 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC. if (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) compliance with the specified requirements would result in hardship or unusual difficultywithout a compensating increase in the level of quality and safety.
Pursuant to 10 CFR 50.55a(g)(4),
ASME Code Class l. 2 and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code.Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," to the extent practical within the limitations of design,
- geometry, and materials of construction of the components.
The regulations require that inservice examination of components and system pressure tests conducted during 'the first ten-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by,reference in 10 CFR 50.55a(b) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein.
The applicable ASME Code,Section XI. for the Palo Verde Nuclear Generating Station. Unit 1. first ten-year inservice inspection (ISI) interval is the 1980 Edition through Winter 1981 addendum.
The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME Code incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein and subject to Commission approval.
l, 971021.0235 97iOi6 PDR ADOCK 05000528 8
Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical for its facility, information shall be submitted to the Commission in support of that determination and a request made for relief from the 'ASME Code requirement.
After evaluation of the determination, pursuant to 10 CFR 50.55a(g)(6)(i),
the Commission may grant relief and may impose alternative requirements that are determined to be authorized by law, will not endanger life. property, or the common defense and security, and are otherwise in the public interest.
giving due consideration to the burden upon the licensee that could result if the requirements were imposed.
.By letter dated June 20.
1997, Arizona Public Service Company submitted to the NRC its request for deferral of the current inservice inspection interval reactor vessel examinations by approximately 110 days beyond the end of the interval coinciding with the eighth refueling outage of the unit, due to major maintenance activities being scheduled during the last outage of the current inspection interval.
The NRC staff has reviewed and evaluated the licensee's request for deferral of the reactor vessel examination, pursuant to 10 CFR 50.55a(a)(3)(i) f'r Palo Verde Unit 1.
- 2. 0 DISCUSSION
~Com onent:
Reactor Vessel Examination Items ASME Code Section XI Cate or Shell welds (B-A), Full Penetration Welds of'ozzles (B-D), Interior of Vessel (B-N-l), Interior Attachments to Vessel (B-N-2), Removable Core Support Structure (8-N-3)
Reference Code Re uirement:
The licensee stated:
"The required examinations shall have been completed during each successive inspection interval in accordance with Table IWB-2412-1.
The inspection period specified may be, decreased or extended by as much as one year to enable an inspection to coincide with a plant outage, within the limits of IWA-2400(c)."
Licensee's Basis for Re uested Relief:
The licensee stated "The last scheduled Unit One refueling outage which falls within the first ten year ISI interval is the Unit One Cycle Seven Refueling Outage (U1R7), which is to begin March 22, 1998.
Currently, the first ten year inter val reactor vessel ISI exams are scheduled during this outage.
There are, however.
a number of emergent maintenance activities which need to be performed during this outage including reactor coolant pump shaft replacements and full station battery replacement.
Therefore, to balance major= maintenance activities
0 II k
between refueling outages, Arizona Public Service Company proposes to move the reactor vessel ISI to the Unit One Cycle 8 (UlR8) outage scheduled for the Fall of 1999.
In accordance with 10 CFR 50.55a(a)(3)(i),
the Alternative Examination proposed by APS, in conjunction with the review of data from the Units 2 and 3 examinations, provides an adequate level of safety and quality."
Licensee's Pro osed Alterantive Examination:
The licensee stated:
"This relief request is for the deferral of, not the exemption from. the code examination requi rements.
The one year extension period allowed for the examination by the ASME Code ends on July 17, 1999 and UlR8 is currently scheduled from September 18, 1999 to November 7, 1999.
Thus, performing the first ten year interval ISI reactor vessel examinations during U1R8 would delay the exams by approximately 110 days beyond the ASME Code allowable one year extension.
This relief request applies specifically to the first ten year ISI interval, no credit is being taken for these exams in the second ten year ISI interval.
The first ten year ISI interval reactor vessel inspections for Units 2 and 3 will be completed during the scheduled Fall 1997 and Fall 1998 Refueling
- Outages, respectively.
Data collected during these examinations will provide for an assessment of the condition of the Unit 1 reactor vessel since the three reactor vessels are of the same material and design.
Should relief be granted, its use will be re-evaluated against indications from Unit 2 inspection data."
Licensee's Im lementation Schedule:
The licensee stated:
. "The ASME Code examinations for the first ten year ISI interval reactor vessel exams will be conducted during U1R8 Refueling Outage scheduled to begin September 18, 1999."
3.0 EVALUATION
~ The staff has reviewed the licensee's request for deferral of the reactor vessel examination by approximately 110 days beyond the first inservice inspection interval due to major maintenance activities being'scheduled during the last outage of the first inspection interval.
As required by the ASME Code,Section XI. an inservice inspection program plan was established for the first inservice inspection interval which scheduled required examinations during inspection periods.
This was reviewed by the staff and no deviations from the applicable Code or the NRC regulations were found.
Due to scheduling of reactor coolant pump shaft replacement during the seventh refueling outage.
the licensee has requested deferral of reactor vessel examinations which were previously scheduled during this outage. to the following outage.
This facilitates balancing of maintenance activities between refueling outages and reduces the duration of the outage.
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peferral of reactor vessel examination to the upcoming outage moves the implementation schedule of the first ten-year inser vice inspection plan by approximately 110 days beyond the end date which would neither affect the duration of the second ten-year inspection interval nor the required examinations.
The staff further finds that the vessel examinations which are now being deferred to the upcoming outage in the second ten-year interval, will only be credited to the first ten-year interval.
Due to the planned deferral of Unit 1 reactor vessel examinations, the licensee has proposed to assess the condition of the vessel from the examination data of the Unit 2 reactor vessel (which is identical to that of Unit 1 in material and in design). to be obtained during the Fall 1997 outage of Unit 2.
The operational readiness of Unit 1 reactor vessel in the interim can be assessed with reasonable confidence within the current inspection period from the nature of degradation detected during Unit 2 reactor vessel examinations.
Therefore, the proposed alternative would provide an acceptable level of quality and safety.
4.0 CONCLUSION
The staff has determined that the planned deferral of Unit 1 reactor vessel examinations by approximately 110 days beyond the Code, allowable extension of the inspection period on the basis of an assessment of material condition as proposed by the licensee in Relief Request No.
10 to the first ten-year inservice inspection plan for Palo Verde Unit 1 provides an acceptable level of quality and safety.
Therefore, the licensee's request for relief from the requirements of the ASME Code,Section XI, 1980 Edition including Winter 1981
- Addendum, subsection IWB-2412, is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the current inspection interval of Palo Verde Unit l.
Principal Contributor:
P. Patnaik Pate:
October 16, 1997
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