ML20202D236

Proposed Tech Spec 5.3.1,deleting Max Fuel Rod U Weight Limit

ML20202D236
Person / Time
Site:	Farley
Issue date:	07/08/1986
From:	ALABAMA POWER CO.
To:
Shared Package
ML20202D223	List: ML20202D218 ML20202D236
References
TAC-61949, NUDOCS 8607140076
Download: ML20202D236 (3)

Text

f . .

DESIGN FEATURES 5.3 REACTOR CORE FUEL ASSEMBLIES 5.3.1 The reactor core shall contain 157 fuel assemblies with each fuel assembly containing 264 fuel rods clad with Zircaloy -4. Each fuel rod shall have a nominal active fuel length of 144 inches. The initial core loading shall have a maximum enrichment of 3.2 weight percent U-235. Reload fuel shall be similar in physical design to the initial core loading and shall have a maximum enrichment of 4.3 weight percent U-235.

CONTROL R0D ASSEMBLIES 5.3.2 The reactor core shall contain 48 full length and no part length control rod assemblies. The full length control rod assemblies shall contain a nominal 142 inches of absorber material. The nominal values of absorber material shall be 80 percent silver,15 percent indium and 5 percent cadmium. All control rods shall be clad with stainless steel tubing.

5.4 REACTOR COOLANT SYSTEM DESIGN PRESSURE AND TEMPERATURE 5.4.1 The reactor coolant system is designed and shall be maintained:

a. In accordance with the code requirements specified in Section 5.2 of the FSAR, with allowance for normal degradation pursuant to the applicable Surveillance Requirements,

b. For a pressure of 2485 psig, and

c. For a temperature of 650 F, except for the pressurizer which is 680 F.

VOLUME 5.4.2 The total water and steam volume of the reactor coolan' cystem is 9723 + 100 cubic feet at a nominal Tavg of 525"F.

5.5 METEOROLOGICAL TOWER LOCATION 5.5.1 The meteorological tower shall be located as shown on Figure 5.1-1.

8607140076 860708 PDR ADOCK 05000348 P PDR l

FARLEY-UNIT 1 5-6 AMENDMENT N0.

t . .

i ATTACHMENT 2 l Significant Hazards Evaluation Pursuant to 10 CFR 50.92 for the Proposed Design Features Section of the Technical Specifications Proposed Change The proposed change to Design Features section 5.3.1 of the Farley Nuclear Plant Unit 1 Technical Specifications deletes the maximum fuel rod uranium weight limit of 1,766 grams. The purpose of the change is to permit the use of fuel assemblies with fuel rod uranium weights over the limit and also to reflect the relative insensitivity of the safety analyses to this parameter.

Background

Design Features Section 5.3.1, Fuel Assemblies, of the Technical Specifications identifies a maximum total fuel rod weight of 1,766 grams of uranium. Recent improvements to fuel design, including chamfered pellets with a reduced dish and an as-built density increase, have increased fuel weight slightly. The weight increases may cause fuel rod uranium weight to exceed the specified maximum of 1,766 grams. This change will delete the specified maximum veight because this limit is not significant to the safe operation of Farley Nuclear Plant.

Although a number of safety analyses are affected indirectly by fuel weight, the analyses are more sensitive to fuel configuration, length, enrich =ent and physical design which are also specified in the plant Technical Specifications. The Technical Specifications limit power and power distribution, thus controlling the fission rate and the rate of decay heat production. Fuel rod weight does not have any direct bearing on the power limits, power operating level, or decay heat rate. The composition of the fuel is closely monitored to assure acceptable fuel performance. The fuel weight changes that could be made in absence of this Technical Specification limit are not of sufficient magnitude to cause a significant difference in fuel performance as analyzed by Westinghouse. There are no expected observable changes in normal operation due to the noted fuel rod weight changes, and the remaining fuel parameters listed in the Technical Specifications are considered in the Reload Safety Evaluation.

Other Design Basis Events were examined to assess the effects of possible changes in fuel rod uranium weight. Fuel rod uranium weight will only change as a result of a specific change in the physical design, which is addressed in the Reload Safety Evaluation, or within the manufacturing tolerances, in which case the changes in fuel rod uranium weight are relatively insignificant and i

are accounted for in the safety analyses. Changes in nuclear design resulting For

' from fuel rod uranium weight changes are controlled as discussed above.

these changes, the effect on new and spent fuel criticality and fuel handling analyses remain bounded by the existing analyses and Technical Specification Design Feature limits. Fuel-handling equipment and procedures are not affected by these weight changes. Seismic /lDCA analyses contain sufficient conservatism to bound these weight changes. Other accident analyses are not affected by fuel rod uranium weight as a direct parameter, and the existing analyses remain bounding.

ATTACHMENT 2 Page 2 Analysis Alabama Power Company has reviewed the requirements of 10 CFR 50.92 as they relate to the proposed change to Design Features Section 5.3.1 and considers the proposed change to not involve a significant hazards consideration. In support of this e,onclusion the following analysis is provided:

1. The proposed change will not significantly increase the probability or consequences of an accident previously evaluated because variation in fuel rod uranium weight that can occur even in absence of this Technical Specification limit is small based on other fuel design constraints, e.g.,

rod diameter, gap size, UO2 density and active fuel length. All of these provide some limit on the variation in fuel rod uranium weight. The current safety analyses are not based directly on fuel rod uranium weight, but rather on design parameters such as power and fuel dimensions. These parameters are either not affected at all by fuel rod uranium weight, or are only slightly affected. However, a review of design parameters which may be affected indicates that a change in fuel weight does not cause other design parameters to exceed the values assumed in the various safety analyses, or to cause acceptance criteria to be exceeded. The effects are not significant with respect to measured nuclear parameters (pcwer, power distribution, nuclear coefficients), i.e., they remain within their Technical Specification limits. Thus the proposed change does not involve a significant increase in the probability or consequences of a previously evaluated accident.

2. The proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated. All of the fuel contained in the fuel rod is similar to and designed to function similar to previous fuel. Thus, the existing safety analyses, including the new and spent fuel storage criticality analyses, bound the proposed change.

Therefore, the proposed change is considered to be administrative in nature and the creation of a new, different kind of accident from any previously evaluated accident is not considered a possibility.

3. The proposed change wi31 not involve a reduction in a margin of safety because the margin of safety is maintained by adherence to other fuel related Technical Specification limits and the FSAR design bases. The deletion of fuel rod uranium weight limits in Technical Specifications Design Features Section 5.3.1 does not directly affect any safety system or the safety limits and therefore does not reduce the plant margin of safety.

Conclusion Based on the analysis provided herewith, Alabama Power Company has determined that the proposed Technical Specification change will Tot significantly increase the probability or consequences of an accident previously evaluated, create the possibility of a new or different kind of accident from any accident previously evaluated, or involve a significant reduction in a margin of safety. Therefora, Alabama Power Company has determined that the proposed change meets the requirements of 10 CFR 50.92 and does not involve a significant hazards consideration.

_. . .__ ___ __ _____ _ _ . __ _