ML20206L437
| ML20206L437 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 05/07/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20206L435 | List: |
| References | |
| NUDOCS 9905140021 | |
| Download: ML20206L437 (4) | |
Text
- Utgk UNITED STATES p
NUCLEAR REGULATORY COMMIS810N
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'U WASHINGTON, D.C. spee64001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.138. TO FACILITY OPERATING LICENSE NO. NPF-29 ENTERGY OPERATIONS. INC.. ET AL.
GRAND GULF NUCLEAR STATION. UNIT 1 q
DOCKET NO. 50-416
1.0 INTRODUCTION
By letter dated May 31,1996, Entergy Operations, Inc. (EOl or the licensee), submitted a request for changes to the Grand Gulf Nuclear Station, Unit 1 (GGNS) Technical Specifications (TSs), Section 3.9.1, " Refueling Equipment interlocks." The original notice was published in the Federal Register on June 16,1996 (61 FR 31178). Additionalinformation was provided on September 30,1996, that did not change the scope of the original application and the initial proposed no significant hazards consideration determination.
Subsequently, in a letter dated January 12,1999, the licensee submitted a proposed amendment that superseded, in its entirety, the original May 31,1996, application and supplement. The new application was noticed in the Federal Renister on February 10,1999 (64 FR 6695), and it was stated that the notice associated with the original May 31,1996, application was being superseded.
The proposed changes would revise TS Limiting Condition for Operation (LCO) 3.9.1,
" Refueling Equipment Interlocks," by adding an attemative to the current action for one or more inoperable refueling equipment interlocks. The current action is to " suspend in-vessel fuel movement with equipment associated with the inoperable interlock (s.)" The alternative action will be to (1) insert a control rod withdrawal block, and (2) verify all control rods are fully inserted in core cells containing one or more fuel assemblies. The amendment would alco revise the Bases for LCO 3.9.1 actions to describe the alternative actions.
2.0 BACKGROUND
Refueling equipment interlocks restrict the operation of the refueling equipment or the withdrawal of control rods to reinforce procedures that prevent the reactor from achieving criticality during refueling operations. The refueling interlock circuitry senses the conditions of the refueling equipment and control rods. Depending on the sensed conditions, interlocks are actuated to prevent the operation of the refueling equipment or the withdrawal of control rods.
General Design Criterion (GDC) 26 of 10 CFR Part 50, Appendix A, requires that one of the two required independent reactivity control systems be capable of holding the reactor core subcritical under cold conditions. Therefore, two channels of instrumentation are provided.
One or both channels receive input from (1) the position of the refueling platform, (2) the loading of the refueling platform main hoist, (3) the full insertion of all control rods, and (4) the 9905140021 990507 PDR ADOCK 05000416 P
- reactor mode switch. With the mode switch in the shutdown or refueling position, the indicated conditions are combined in the logic circuits to determine if all restrictions on refueling equipment operations and control rod insertion are satisfied.
To prevent criticality during refueling, the refueling interlocks ensure that fuel assemblies are not loaded with any control rod withdrawn. To preclude these conditions from developing, the all-rods-in, the refueling platform position, and the refueling platform main hoist fuel loaded inputs are required to be operable. These inputs are combined in logic circuits that provide refueling equipment or control rod blocks to prevent operations that could result in criticality during refueling operations.
The purpose of the proposed amendment is to provide an additional alternative action to permit the licensee to continue core alterations in the event the refueling equipment interlocks become inoperable.
3.0 EVALUATION The original TS amendment request dated May 31,1996, and the additional information provided by the licensee on September 30,1996, was evaluated under the joint Nuclear Regulatory Commission (NRC) - Nuclear Energy Institute Technical Specification Task Force (TSTF) process. The TSTF process enables plants that have adopted the improved Standard Technical Specifications (STS or ITS) to propose, and have approved, generic changes to the ITS. This process also ensures that the iTS remain, in fact, a true standard for plants of similar design. The proposed license amendment to TS Section 3.9.1, " Refueling Equipment Interlocks," submitted by EOl was identified as "TSTF-225." The changes proposed under this TSTF affected NUREG 1433 and NUREG-1434. These NUREGs serve as the bases for the General Electric (GE) BWR/4 and BWR/6 ITS respectively. On April 20,1998, TSTF-225 was approved by the Technical Specifications Branch.
On February 21,1995, License Amendment No.120 to NPF-29 approved GGNS's conversion to the BWR/6 ITS based upon NUREG-1434. GGNS has been operating under the ITS since that time. The January 12,1999, amendment request incorporated changes to the Required Actions paragraph in order to be consistent with changes to the BWR ITS NUREGs 1433 and 1434 approved under TSTF-225. The licensee has based this TS amendment request on TSTF-225, which applies to the GGNS TSs.
The proposed changes to the Required Actions for LCO 3.9.1 will improve consistency within the TS with respect to the Required Actions for LCO 3.9.4," Control Rod Position Indication."
LCO 3.9.4 controls the operability of the control rod position indicators, which is a support system for the refueling interlocks controlled by LCO 3.9.1 since the position indicators provide information to the all-rods-in interlock. LCO 3.9.4 requires that, when one or more control rods do not have the required position indication operable, all insertable control rods be inserted and fuel movement and control rod withdrawal be suspended (Required Actions A.1.1, A.1.2 and A.1.3), or that the associated control rod (s) be inserted and disarmed (Required Actions A.2.1 and A.2.2.) If Required Actions A.2.1 and A.2.2 are complied-with, then refueling activities can continue. The proposed Required Actions for LCO 3.9.1 are consistent with the current Required Actions for LCO 3.9.4 in that they require either fuel movement be suspended or control rod withdrawal be blocked, and that all control rods required to be inserted be verified to be inserted.
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i 3-As discussed in the Bases for the current Required Action, the purpose of the current requirement is to ensure that operations are not performed with equipment that would potentially not be blocked from unacceptable operations (e.g., loading fuel into a cell with a l
control rod withdrawn). The method that the refueling equipment interlocks use to perform their i
function whenever fuel is being moved in the reactor vessel is to block control rod withdrawal.
Conversely, when a control rod is withdrawn (except as allowed by LCO 3.10.6) the refueling interlocks prevent fuel from being moved in the vessel. The proposed change will allow the refueling interlocks to be inoperable and fuel movement to continue if a control rod withdrawal l
block is in effect and all control rods are verified to be fully inserted, thereby ensuring that fuel loading will not occur with a control rod inappropriately withdrawn.
The first refueling equipment interlock safety function is to block control rod withdrawal whenever fuel is being moved in the reactor vessel. The proposed alternative Required Actions will perform this function by requiring that a control rod block be placed in effect.
The second refueling equipment interlock safety function is to prevent fuel from being loaded l
into the vossel when a control rod is withdrawn. This function will continue to be performed by the proposed attemate LCO 3.9.1 Required Actions.. Required Action A.2,1 will require that a 3
control rod block be placed in effect thereby ensuring that control rods are not subsequently
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inappropriately withdrawn. Following placing the control rod withdrawal block in effect, Required Action A.2.2 will require that all control rods be verified to be fully inserted in core cells j
containing one or more fuel assemblies. This verification is in addition to the requirements to
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periodically verify control rod position in Surveillance Requirement (SR) 3.9.3.1 and i
SR 3.10.6.2. These proposed Required Actions will ensure that control rods are not withdrawn 3
and cannot be inappropriately withdrawn because an electrical or hydraulic block to control rod withdrawal is in place. Like Required Action A.1, this will ensure that unacceptable operations are blocked (e.g., loading fuel into a cell with a control rod withdrawn). In addition, Required Action A.2.2 is consistent with the current allowances of LCO 3.10.6.
Therefore, the staff considers this change acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Mississippi State official was notified of the proposed issuance of the amendment. The State official had no comments.
5.0 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 l
Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (64 FR 6695, February 10,1999). Accordingly, the amendment meets the eligibility criteria for j
categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission'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.
Principal Contributor: R. J. Fretz Date: May 7, 1999 l
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