ML18153A394
| ML18153A394 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 11/05/1997 |
| From: | VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| Shared Package | |
| ML18151A980 | List: |
| References | |
| NUDOCS 9711120196 | |
| Download: ML18153A394 (7) | |
Text
Attachment 2 Proposed Technical Specifications Change 9711120196 971105 PDR ADOCK 05000280 p
e TS 5.3-2
- 3. Reload fuel will be similar in design to the initial core. The enrichment of reload fuel will not exceed 4.3 weight percent of U-235.
- 4. Burnable poison rods are incorporated in the initial core. There are 816 poison rods in the form of 12 rod clusters, which are located in vacant control rod assembly guide thimbles. The burnable poison rods consist of pyrex clad with stainless steel.
- 5. There are 48 full-length control rod assemblies in the reactor core. The full length control rod assemblies contain a 144-inch length of silver-indium-cadmium alloy clad with stainless steel.
- 6. Surry Unit 1, Cycle 4, Surry Unit 2, Cycle 3, and subsequent cores will meet the following criteria at all times during the operation lifetime.
- a. Hot channel factor limits as specified in Section 3.12 shall be met.
Amendment Nos.
35000 30000 25000 I-Cl 20000 3':
~ -
C.
- s C:...
- s cc
- a 15000 E
Q)
Ill Ill
<C 10000 5000 0
ti T.S. Figure 5.4-1 225~ ppm ~oron I/
in P ol Water
/
f.7 V
/
K<0.~5 V
Regifn:
V Acceptable Regi~n
/
V V
/
V V
Unacc eptable Re! ~ion V
I I/
I/
1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 Initial Fuel Enrichment (w/o U-235)
FIGURE 5.4-1 MINIMUM FUEL EXPOSURE VERSUS INITIAL ENRICHMENT TO PREVENT CRITICALITY IN DAMAGED RACKS Amendment Nos.
e TS 5.4-2 assemblies to ensure keff ~ 0.95, even if unborated water were used to fill the spent fuel storage pit. The spent fuel pool is divided into a two-region storage pool. Region 1 comprises the first three rows of fuel racks (324 storage locations) adjacent to the Fuel Building Trolley Load Block. Region 2 comprises the remainder of the fuel racks in the fuel pool. During spent fuel cask handling, Region 1 is limited to storage of spent fuel assemblies which have decayed at least 150 days after discharge and shall be restricted to those assemblies in the "acceptable" domain of Figure 5.4-1. Administrative controls with written procedures will be employed in the selection and placement of these assemblies.
The enrichment of the fuel stored in the spent fuel racks shall not exceed 4.3 weight percent of U-235.
C.
Whenever there is spent fuel in the spent fuel pit, the pit shall be filled with borated water at a boron concentration not less than 2300* ppm to match that used in the reactor cavity and refueling canal during refueling operations.
D.
The only drain which can be connected to the spent fuel storage area is that in the reactor cavity. The strict step-by-step procedures used during refueling ensure that the gate valve on the fuel transfer tube which connects the spent fuel storage area with the reactor cavity is closed before draining of the cavity commences. In addition, the procedures require placing the bolted blank flange on the fuel transfer tube as soon as the reactor cavity is drained.
This limit takes effect at the time the Unit 2 reactor cavity is flooded following the end of Operating Cycle 10.
References FSAR Section 9.5 Fuel Pit Cooling System FSAR Section 9.12 Fuel Handling System Amendment Nos.
e e
Significant Hazards Consideration
SIGNIFICANT HAZARDS CONSIDERATION Virginia Electric and Power Company proposes to increase the maximum fuel enrichment for Surry Units 1 and 2 from the current Technical Specifications limit of 4.1 weight percent U235, to 4.3 weight percent U235.
Use of a higher initial enrichment will permit fuel discharge burnups more compatible with the current lead rod burnup limit of 60,000 MWD/MTU, resulting in fuel cycle cost savings while continuing to satisfy our cycle energy requirements. No change in the fuel bumup limits is being requested at this time.
Previous evaluations of the safety impact of operation with high bumup fuel were based on assessments that were valid for enrichments which exceed the requested 4.3 weight percent U235.
Therefore the proposed enrichment increase will not affect the types or amounts of radiological effluents that may be released offsite. The impact on the new and spent fuel storage areas, which are common to Surry Units 1 and 2, was analyzed to ensure that these areas will remain safe under the criticality specifications set forth in the Standard Review Plan (NUREG-0800). The effect of a higher initial fuel enrichment on other possible areas of consideration was also reviewed, and no adverse impacts were identified.
Virginia Electric and Power Company has reviewed the Technical Specifications changes for Surry Units 1 and 2 against the criteria of 10 CFR 50. 92. It has been concluded that use of fuel with the slightly higher initial enrichment does not involve a significant hazards consideration as defined in 10 CFR 50.92. An increase in the maximum initial fuel enrichment from 4.1 to 4.3
- h u235
- 11 we1g t percent w1 not:
- 1. Involve a significant increase in the probability of occurrence or the consequences of an accident previously evaluated. The only accidents for which the probability of occurrence is potentially affected by the fuel enrichment involve criticality events during handling and storage. Analyses have demonstrated that the K-effective will be low enough to ensure subcriticality during both normal operation and under postulated accident conditions during the handling and storage of both new and spent fuel. Therefore, the probability of occurrence of criticality during fuel handling or storage is not increased. Safety analyses of record are based on inputs which bound the proposed increase in fuel enrichment. Since no changes to the fuel bumup limits are requested, the radiological consequences of previously evaluated accident scenarios will not be increased. Therefore, neither the probability of occurrence nor the consequences of any accident previously evaluated is significantly increased.
- 2. Create the possibility for a new or different type of accident from any accident previously evaluated.
Fuel with the higher initial enrichment will meet all applicable design criteria and will operate within existing Technical Specifications limits. Adherence to these standards and criteria precludes new challenges to components and systems that could introduce a new type of accident. All design and performance criteria will continue to be met. In addition, the use of a slightly higher initial fuel enrichment does not involve any alteration
r, to plant equipment or procedures which would introduce any new or unique operational modes or accident precursors. Therefore, the possibility for a new or different kind of accident from any accident previously evaluated is not created.
- 3. Involve a significant reduction in the margin of safety. Surry Units 1 and 2 will continue to operate in compliance with the Technical Specifications, ensuring that the plants continue to provide acceptable levels of protection for the health and safety of the public. The Technical Specifications are based upon assumption made in the safety and accident analyses, including those relating to the fuel enrichment and the design of the fuel storage areas. Analyses have demonstrated that subcriticality will be ensured during fuel storage and handling accident scenarios for both new and spent fuel. Additionally, safety analyses of record for core operation will remain applicable for Surry Unit 1 and 2 cores which use fuel with the slightly higher U 235 enrichment. Therefore, the regulated margin of safety as defined in the Bases to the Surry Technical Specifications is not reduced.
Based on the preceding information, it has been determined that the use of fuel with an initial enrichment of up to 4.3 weight percent U235 satisfies the no significant hazards consideration criteria of 10 CFR 50.92.