United States Nuclear Regulatory Commission - Protecting People and the Environment

Alternative Requirements for Fuel Assemblies in Design Features Section of Technical Specifications (Generic Letter 90-02)


				                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                            WASHINGTON, D.C. 20555

                               February 1, 1990

TO ALL LIGHT-WATER REACTOR LICENSEES AND APPLICANTS

SUEJECT: ALTERNATIVE REQUJREMENTS FOR FUEL ASSEMBLIES IN DESIGN FEATURES 
SECTION OF TECHNICAL SPECIFICATIONS (Generic Letter 90-02)

Technical Specifications (TS) include design requirements for fuel
assemblies  in Section 5, "Design Features." On a plant-specific basis,
the staff has  approved changes to these requirements that provide
flexibility for improved  fuel performance by permitting timely removal of
fuel rods that are found to  be leaking during a refueling outage or are
determined to be probable sources  of future leakage. Because these
improvements in a licensee's fuel performance  program will provide for
reductions in future occupational radiation exposure  and plant
radiological releases, this alternative is being made available to  all
plants as a line-item improvement in TS.

The requirements included in Section 5 of the TS or "Design Features"
address  those features of the facility such as materials of construction
and geometric  arrangements which, if altered or modified, would have a
significant effect on  safety and are not covered under other sections of
the TS on "Safety Limits,"  "Limiting Conditions for Operation, or
"Surveillance Requirements." Recently,  the staff approved a lead-plant
request to modify the requirements for "Fuel  assemblies," Specification
5.3.1, for the McGuire and Catawba plants. That  change allows the
substitution of Zircaloy-4 or stainless steel filler rods or  open water
channels for fuel rods in fuel assemblies if justified by cycle-specific
reload analyses using an NRC-approved methodology. In addition, the 
change requires that a special report describing the number of rods
replaced  be submitted to NRC if more than 30 rods in the core, or 10 rods
in any  assembly, are replaced per refueling.

The enclosed guidance addresses the preparation of a license amendment
request  for this change to TS. Licensees and applicants are encouraged to

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propose changes to their TS that are consistent with the guidance in the 
enclosure. Conforming amendment requests will be expeditiously reviewed by
the  NRC Project manager for the facility. Please contact the Project
Manager if  you have questions or this matter.

Sincerely,

James G. Partlow
Associate Director for Projects 
Office of Nuclear Reactor Regulation

Enclosures:
1. Guidance for the Modification of the Requirements for Fuel Assemblies
   in  the Design Features Section of Technical Specifications
2. List of Most Recently Issued NRC Generic Letters Generic Letter 90-02

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Generic Letter 90-02                                          Enclosure

GUIDANCE FOR THE MODIFICATION OF THE REQUIREMENTS FOR FUEL ASSEMBLIES IN
THE DESIGN FEATURES SECTION OF TECHNICAL SPECIFICATIONS

INTRODUCTION

This enclosure provides guidance for the preparation of a license
amendment  request to modify the Technical Specifications (TS)
requirements for "Fuel  Assemblies" in the Section 5, "Design Features,"
of TS. This change to the TS  permits the substitution of Zircaloy-4 or
stainless steel filler rods or open  water channels for fuel rods in fuel
assemblies if justified by cycle-specific  reload analyses.

DISCUSSION

The requirements for fuel assemblies specify the quantity of fuel
assemblies  and the number of fuel rods per assembly. Flexibility to
deviate from the  number of fuel rods per assembly is desirable to permit
timely removal of fuel  rods that are found to be leaking during a
refueling outage or are determined  to be probable sources of future
leakage. This improvement in the licensee's  fuel performance program will
provide for reductions in future occupational  radiation exposure and
plant radiological releases.

The substitution of filler rods or open water channels for fuel rods is 
acceptable when justified by cycle-specific reload analyses using an NRC-
approved methodology. This reload analyses will demonstrate that existing 
design limits and safety analyses criteria are met in advance of the next 
operating cycle. An "NRC-approved methodology" includes those
methodologies  acknowledged in the Final Safety Analysis Report and
applied in support of the  issuance of the original operating license. It
also includes those subsequent  methodologies that have been submitted to
and accepted by the NRC staff as  amendments to the operating license.

If the reconstitution of fuel assemblies through the use of filler rods or 
open water channels is extensive, this information should be reported to
NRC.  Therefore, if more than 30 rods in the core, or 10 rods in any
assembly, are  replaced during a refueling, a special report describing
the number of rods  replaced must be submitted to NRC in accordance with
the provisions of the TS  for special reports.

The attached example is a typical specification for fuel assemblies with
the  required modifications shown underlined. Proposed changes to plant TS
should  follow this guidance.

SUMMARY

The modification of the "Design Features" section of the TS on "Fuel 
Assemblies" will not result in modifications to fuel assemblies that would 
have a significant effect on safety because of the necessity to justify
such  changes using an NRC-approved methodology. This requirement will
confirm  conformance to existing design limits and that safety analyses
criteria are  met before operation during the next fuel cycle. A license
amendment request  to modify the requirements for "Fuel Assemblies" that
1s consistent with the  guidance provided will result in flexibility for
improved fuel performance.

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Generic Letter 90-02                                          Enclosure

                     MODEL TECHNICAL SPECIFICATION CHANGE
                          (CHANGES SHOWN UNDERLINED)

5.0 DESIGN FEATURES 

5.3 REACTOR CORE

FUEL ASSEMBLIES

5.3.1 The core shall contain 193 fuel assemblies with each fuel assembly 
nominally containing 264 fuel rods clad with Zircaloy-4, except that 
substitution of Zircaloy-4 or stainless steel filler rods or open water 
channels for fuel rods may be made in fuel assemblies if justified by
cycle- specific reload analyses using an NRC-approved methodology. Should
more than  30 rods in the core or 10 rods in any assembly, be replaced per
refueling, a  special report describing the number of rods replaced shall
be submitted to  the Commission pursuant to Specification 6.9.2 within 30
days after cycle  startup. Each fuel rod shall have a nominal active fuel
length of 144 inches.  Reload fuel shall be similar in physical design to
the initial core loading  and shall have a maximum enrichment of 4.0
weight percent U-235.

Specification 6.9.2 of the Standard Technical Specifications (STS) states:

Special reports shall be submitted to the Regional Administrator of the 
Regional Office of the NRC within the time period specified for each
report.

Plants whose Technical Specifications do not include STS 6.9.2 should
ensure  that the revised Specification 5.3.1 includes reporting
requirements  equivalent to the combination of STS 5.3.1 and 6.9.2 above.

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