ML20141D598
| ML20141D598 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 06/24/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20141D595 | List: |
| References | |
| NUDOCS 9706270274 | |
| Download: ML20141D598 (8) | |
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UNITED STATES l
j NUCLEAR REGULATORY COMMISSION g.'
WA5HiNGToN, D.C. 20066-0001 o
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1AEfTY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION BEL 8TED TO AMENDMENT NO. 53 TO FACILITY OPERATING LICENSE NO. NPF-86 NORTH ATLANTIC ENERGY SERVICE CORPORATION SEABROOK STATION. UNIT 1 DOCKET NO. 50-443 l
1.0 INTRODUCTION
By letter dated May 29, 1997, North Atlantic Energy Service Corporation (North Atlantic) submitted an application for license amendment for a change to the Seabrook Station, Unit No. 1 (Seabrook) Appendix A Technical Specifications.
The amendment would revise Technical Specification 5.3.1, which specifies some fuel assembly design features, by replacing the reference to "zircaloy," the currently identified fuel rod cladding material, with "ZIRLO cr Zircaloy-4" to identify explicitly the NRC-approved Westinghouse fuel asseroly designs in use at Seabrook.
2.0 BACKGROUND
The Technical Specifications approved when Seabrook was licensed initially incorporated, in part, the following description of the fuel assemblies comprising the reactor core:-
5.3.1 The core shall contain 193 fuel assemblies with each fuel assembly containing 264 fuel rods clad with Zircaloy-4....
This partial description of the fuel assemblies remained unchanged until -
Amendment 33 was issued on November 23, 1994. That amendment modified the Seabrook Technical Specifications to permit operation of the reactor core with an expanded axi.a1 flux difference band (wide-band operation) and to allow for fuel design enhancements. With regard to the description of the Seabrook fuel assemblies, North Atlantic stated that the purpose of the change to Technical Specification 5.3.1 was "...to allow the possibility of future implementation of ZIRLO cladding." Amendment.33 modified the partial fuel assembly descrip}: ion stated above by changing "Zircaloy-4" to " zirconium alloy" as follows l
5.3.1 The core shall contain 193 fuel assemblies with each fuel assembly containing 264 fuel rods i: lad with a zirconium alloy....
It is no longer acceptable to the staff to describe the fuel rod clad t
material as merely "a zirconium alloy".
The staff will only accept wording that identifies the specific fuel rod clad alloy.
l 9706270274 970624 PDR ADOCK 05000443 P
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l The next change to Technical Specification 5.3.1 was made by Amendment 50, issued on March 12, 1997, that inadvertently incorporated a typographical error contained in the proposed replacement pages submitted with North Atlantic's application.
The error caused the partial fuel assembly description in Technical Specification 5.3.1 to revert to the original wording:
l 5.3.1 The core shall contain 193 fuel assemblies with each fuel assembly containing 264 fuel rods clad with Zircaloy-4....
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Amendment 51 issued May 13, 1997, again changed Technical Specification 5.3.1.
The changes approved by Amendment 51 allow the use of solid stainless steel or zirconium alloy filler rods in fuel assemblies to replace failed er damaged fuel rods. North Atlantic's submittal was in accordance with the guidance i
provided in Generic Letter 90-02, Supplement 1.
The Generic Letter 90-02, j
Supplement 1, model technical specification stated:
5.3.1 The reactor shall contain [
] fuel assemblies.
Each assembly i
shall consist of a matrix of zircaloy clad fuel rods with an initial t
compositic.a of natural or slightly enriched uranium dioxide as fuel material [, and water rods).
Limited substitutions of zirconium alloy or 4
stainless steel filler rods for fuel rods, in accordance with NRC-approved applications of fuel rod configurations, may be used.
Fuel i
assemblies shall be limited to those fuel designs that have been analyzed j
with applicable NRC staff-approved codes and methods, and shown by tests j
or analyses'tu comply with all fuel safety design bases.
A limited number of lead test assemblies that have not completed representative j
testing may be placed in non-limiting core regions.
Information to be added to the generic letter model technical specification by i
licensees as appropriate is indicated by (
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4 3.0 EVALUATION s
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The Seabrook fuel design used for Operational Cycles 1 through 4 incorporated Zircaloy-4 cladding.
For Operational Cycle 5, the core design incorporated Vantage SH fuel utilizing ZIRLO cladding material in addition to the 17X17 STD 1
fuel assemblies with Zircaloy-4 cladding. North Atlantic plans to use Vantage SH and 17X17 STD fuel assemblies with ZIRLO and Zircaloy-4 cladding material for future operational cycles.
The proposed change will explicitly recognize in Technical Specification 5.3.1 the NRC-approved Westinghouse fuel assembly design in use at Seabrook consisting of "ZIRLO or Zircaloy-4" fuel cladding material.
The Safety Evaluating supporting Amendment No. 33 to the Seabrook Operating License noted the implementation of fuel design enhancements, namely, low pressure drop Zircaloy grids and ZIRLO cladding. That Safety Evaluation addressed the staff's review of North Atlantic's submittals supporting the proposed changes including reanalyses of those transients and accidents that are discussed in the Seabrook Station's Updated Final Safety Analysis Report (UFSAR), Section 2.2 of the Amendment 33 Safety Evaluation stated:
The revised LOCA analysis assumes the swelling / burst characteristics of This the zirlo fuel cladding which bounds the Zircaloy cladding as well.TS permits flexibility for future implementation of ziric cladding.
5.3.1 is revised accordingly.
The staff approved the Westinghouse ZIRLO fuel design descrined in Topical Report WCAP-12610-P-A, " VANTAGE + Fue] Assembly Reference Core Report," in a l
I The staff also approved loss-of-safety evaluation dated July 1,1991.
coolant accident (LOCA) methodologies described in Westinghouse topical report WCAP-12610-P-A. The staff has reviewed the Seabrook VANTAGE SH Z design, thermal-mechanical analyses, and LOCA methodologies described in WCAP 12610-P-A, and ha concluded that the VANTAGE SH ZIRLO fuel design is acceptable, and the LOCA analyses demcastrate conformance with the criteria given in 10 CFR E0.44, 10 CFR 50.46, and Appendix K to 10 CF Seabrook.
ZIRLO is similar in chemical composition, physical, 10 CFR 50.44 and 50.46.and mechanical properties to Zircaloy-4, but ZIRLO performance and dimensional stability. rod cladding integrity and fuel assemb ZIRLO clad fuel rods will satisfy the same design bases as Zirc Seabrook Technical rods.
assemblies manufactured with ZIRLO clad fuel rods.
Specification 6.8.1.6.b. identifies the approved analytical methods to be used for determining core operating limits and includes those previously reviewed and approved analytical methods to support the operation of Seabrook with fuel rods clad with either Zircaloy or ZIRLO.
Based upon the above, the staff concludes that it is acceptable to change Technical Specification 5.3.1 to identify explicitly the NRC-approved Accordingly, Westinghouse fuel assembly designs for use at Seabrook.
Technical Specification 5.3.1 is changed to state the following:
Each assembly The reactor shall contain 193 fuel assemblies.
shall consist of a matrix of ZIRLO or Zircaloy-4 clad fuel rods with an 5.3.1 initial composition of natural or slightly enriched uranium dioxide (U0 )
2 Limited substitutions of zirconium alloy or stainless as fuel material.
steel filler rods for fuel rods, in accordance with NRC-approved Fuel assemblies applications of fuel rod configurations, may be used.shall be limit apolicable NRC staff-approved codes and methods and shown by tests ora limited num analyses to comply with all fuel safety design bases.of lead test a Reload fuel shall be similar may be placed in nonlimiting core regions.in physical design to the enrichment of 5.0 weight percent U-235.
The VANTAGE + and VANTAGE SH ZIRLO designations refer to the identical 2
fuel design.
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l 4.0 STATEMENT OF EXIGENT CIRCUMSTANCES i
i The Comission's regulation as stated in 10 CFR 50.91, provides special l
exceptions for the issuance of amendments when the usual 30-day public notice l
cannot be met. One type of special exception is an exigency.
An exigency exists when the staff and the licensee need to act quickly and time does not permit the staff to publish a Federal Reaister notice allowing 30 days for prior public comment, and the staff also determines that the amendment involves no significant hazards consideration.
In accordance with 10 CFR 50.91(a)(6)(i)(B), the staff used local media to provide reasonable notice to the public in the area surrounding the Seabrook Station of the proposed amendment and proposed finding of no significant hazards consideration, and reasonable opportunity to coment thereon.
The notice was published in Foster's Daily Democrat and in the Egrtsmouth Herald on June 4, 1997. Coments were received and are detailed in Section 5.
I Seabrook is currently in Refueling Outgge 5 and the station is scheduled to restart on approximately June 24, 1997.
Thus, the amendment is needed i
before expiration of the normal 30 day coment period provided for in 10 CFR 50.91.
North Atlantic requested NRC review on an exigent basis pursuant to the provisions of 10 CFR 50.91(a)(6). The exigent circumstances i
that have occurred are described below.
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During a site visit on May 23, 1997, the NRC Project Manager identified that j
the Technical Specifications must be revised to identify the specific fuel cladding materials in use at the Seabrook Station. North Atlantic concurred i
with the NRC's assessment and on May 29, 1997, submitted an application for a i
license amendment to correct Technical Specification 5.3.1 to identify the specific fuel assembly cladding material approved fu use at Seabrook.
The NRC staff determined that North Atlantic has exercised its best efforts to make a timely application for amendment in that the application was submitted promptlyaftertheipentificationoftheneedforthechangetoTechnical Specification 5.3.1.
Accordingly, the Comission has determined, pursuant to 50.91(a)(6), that the amendment may be processed on an expedited basis in that exigent circumstances exist warranting prompt action, the situation could not have been avoided, and the amendment, as discussed in Section 6.0, does not
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involve a significant hazards consideration.
5.0 COMMENTS d
During the comment period, the Comission received telephone calls from two a
individuals.
The following is a sumary of the coments received.
2 Two coments dealt with the effectiveness of the NRC's procedure for receiving coments from the public outlined in the Public Notice. The coments noted th,at the telephone number provided in the Public Notice was equipped with 3
At the time the application was received, restart was scheduled for 4
June 16, 1997.
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- automated voice-mail capability; thus, if the automated voice-mail system i
responds in the absence of the called individual, collect telephone calls l
cannot be accepted.
Further, one individual stated, that the use of voice-mail raises a concern that other commentors may have attempted to provide 3
comments unsuccessfully, and, therefore, the individual believed public i
comment period should be extended. As a result of these coments, the staff is examining various options to assure that in the future individuals placing collect calls can reach an attended telephone. The staff notes that while collect callers may have had difficulty in recording comments during certain circumstances, the voice-mail system was available otherwise for recording public comments.
Furthermore, the voice-mail system provided j
callers (including telephone system operators).the option of call-forwarding f
to reach an attended telephone.
When the problem was brought to our l
attention, the voice-mail message was removed, and automatic call-forwurding to an attended telephone after four rings was provided for the last 2 days of J
the coment period on this proposed amendment. There is no indication that any individual wishing to comment on the notice was unable to do so, and there j
is no basis for extending the comment period.
i Two individuals commented that the proposed amendment involves a significant l
hazards consideration because there is a problem with the ZIRLO-clad Westinghouse fuel in use at Seabrook; one of these individuals asserted that i
the existence of a steam generator tube leak is relevant to the issue i
because the fuel problems coupled with a steam generator tube leak represents degradation of two of the principal safety barriers, and further degradation cf these barriers could lead to serious public safety consequences.
The i
individual held that the probability and consequences of previously evaluated accidents would be increased, and that margins of public safety would be i
reduced.
The recent fuel experience at Seabrook appears to be due to a combination of several factors such as fuel assembly power history, operational strategy, and core design. There is no indication that the fuel rod cladding material adversely influenced, fuel performance at Seabrook. This amendment makes a change to the materials acceptable for use as fuel rod cladding only.
No other design features of the fuel assemblies used at Seabrook or of the remainder of the facility are involved.
Zircaloy and ZIRLO are similar zirconium-based materials; however, ZIRLO has certain improved physical and mechanical characteristics over those of Zircaloy. The most important of these characteristics is superior corrosion resistance. ZIRLO clad fuel rods are expected to perform better than fuel rods clad with Zircaloy.
Duringeackrefuelingoutage,anyleakingsteamgeneratortubesareidentified and plugged.
Furthermore, each steam generator is examined every two refueling outages (two steam generators per outage) for indications of tube degradation, and any tubes with degradation exceeding predetermined limits are plugged to minimize the potential for failure during operation.
Occasional limited failures of fuel rods and occurrences of leaking steam generator tubes during operation are expected and are provided for in the design and licensing cf the facility.
The recent fuel experience at Seabrook not withstanding, the proposed change to Technical Specification 5.3.1 will
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- not result in the station operating with radioactivity releases greater than that those for which the facility is currently licensed. The effect of this change upon the probability and consequences of previously evaluated accidents and margins of public safety are discussed in Section 6.0.
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6.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION
DETERMINATION i
The Commission has made a final determination that the amendment involves no significant hazards consideration. Under the Commission's regulations in 1
i 10 CFR 50.92 with the prop (c), this means that the operation of the facility in accordance I
osed amendment would not (1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2)
Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.
The Commission has evaluated the proposed changes against the above standards as required by 10 CFR 50.91(a) and has concluded that:
A.
The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated (10 CFR l
50.92(c)(1)) because ZIRLO is similar in chemical composition, physical, and mechanical properties to Zircaloy-4, but ZIRLO has improved corrosion performance and dimensional stability. These characteristics ensure that fuel rod cladding integrity and fuel assembly structural integrity are maintained.
Fuel assemblies manufactured with ZIRLO clad fuel rods meet the same design bases requirements as fuel assemblies manufactured with Zircaloy-4 cladding, and the regulatory requirements of 10 CFR 50.46 are applicable to either material. No concerns have been identified pertaining to reactor operation with a core comprised of fuel assemblies manufactured with Zircaloy-4 clad rods and fuel assemblies manufactured with ZIRLO clad rods.
ZIRLO clad fuel rods do not require a change to the Seabrook reload design and safety analysis limits.
The proposed amendment will not result in a change to any of the process variables that might initiate an accident or affect the radiological release for an accident.
The operating limits will not be changed and the analysis methods to demonstrate operation within the limits will remain in accordance with NRC-approved methodology. The amendment does not involve any changes to facility structures, systems, or components other than the changes to the fuel assemblies.
Radiological consequences of previously evaluated accidents are not increased because the safety analysis dose predictions are not sensitive to the type of cladding material used.
Therefore, the use of ZIRLO fuel rod material does not adversely affect fuel performance or impact nuclear design methodology, and the probability or consequences of accidents previously evaluated in the Seabrook Updated Final Safety Analysis Report are not increased by this change.
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B.
The proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated (10 CFR 50.92(c)(2)) because fuel assemblies manufactured with ZIRLO clad fuel rods will satisfy the same design bases as those currently used for i
Zircaloy-4 clad fuel assemblies. All design and performance criteria will continue to be met by fuel assemblies manufactured with ZIRLO clad i
fuel rods. The use of fuel assemblies manufactured with ZIRLO cladding does not involve any other alteration to facility structures, systems, or components that would introduce any new operational modes or accident initiators. Therefore, the possibility of a new or different kind of accident from any accident previo nij evaluated is not created by this i
change.
4 C.
The change does not involve a significant reduction in a margin of safety (10 CFR 50.92(c)(3)) because the ase of fuel assemblies manufactured with i
ZIRLO clad fuel rods does not change the reactor core reload design and i
safety accident limits.
The use of these fuel assemblies will take into 1
consideration the normal core operating conditions allowed in the Technical Specifications.
Each cycle reload core design will be evaluated using NRC-approved reload design methods.
Based on the above considerations, the staff concludes that the amendment meets the standards set forth in 10 CFR 50.92 for no significant hazards consideration. Therefore, the staff has made a final determination that the l
proposed amendments involve no significant hazards consideration.
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7.0 STATE CONSULTATION
1 In accordance with the Commission's regulations, the New Hampshire and Massachusetts State officials were notified of the proposed issuance of the j
amendment. The New Hampshire official was notified on June 5,1997, and the j
Massachusetts official was notified on June 11, 1997.
The State officials had j
no comments.
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8.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC staff has determined that the amendment involves no significant increase in the amounts and no significant change in the types of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has made a final finding that the amendment involves no significant hazards consideration. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement er environmental assessment need be prepared in connection with the issuance of the amendment.
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9.0 CONCLUSION
I The Comission has concluded, based on the considerations discussed above, i
that: (1) there is reasonable assurance that the health and safety of the i
public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Comission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
4 Principal Contributors:
S. L. Wu A. De Agazio Date:
June 24, 1997 4
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