ML20236X381
| ML20236X381 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 08/03/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20236X377 | List: |
| References | |
| NUDOCS 9808070337 | |
| Download: ML20236X381 (4) | |
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'4 UNITED STATES g
j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20066-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 213 AND 194 TO VIRGINIA ELECTRIC AND POWER COMPANY l
NORTH ANNA POWER STATION. UNITS NO.1 AND NO. 2 DOCKET NOS. 50-338 AND 50-339 l
- 1. INTRODUCTION By letter dated November 5,1997, the Virginia Electric and Power Company (VEPCO, the licensee), submitted a license amendment request to revise the Technical Specifications (TS) for the North Anna Power Station, Units 1 and 2. The amendments would change TS 3/4.9.7, " Refueling Operations, Crane Travel - Spent Fuel Pit," to enable the licensee to move the spent fuel pit (SFP) gates over irradiated fuelin the SFP. The amendment would 3
also add to the TS proper handling and control measures to be instituted when moving the SFP gates over irradiated fuelin the SFP. These handling and control measures would assure that the SFP gates are not dropped. The SFP gates are removed for maintenance and reinstalled in the SFP prior to each refueling outage.
- 2. BACKGROUND i
Three SFP gates weighing 4200 pounds each exist: one at each unit's fuel transfer canal and the other at the spent fuel cask separating wall. Prior to each outage, the gates are removed from the SFP for maintenance. They are moved across the irradiated fuel storage area to the cask handling area where they are lifted out of the SFP. Currently, the gates are transported out of the SFP via safe load paths across empty fuel storage cells. During the Fall 1998 refueling outage and subsequent refueling outages, the licensee cannot maintain safe load paths over empty storage cells during removal of the gates because irradiated fuel will be seated in the cells. Existing TS restricts movement of loads greater than 2500 pounds over irradiated fuel stored in the SFP.
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NUREG-0612. " Control of Heavy Loads at Nuclear Power Plants," provides guidelines for j
licensees to assure safe handling of heavy loads by prohibiting load travel, to the extent I
practicable, over spent fuel assemblies, over the core, and over safety-related equipment.
The NUREG also recommends in Section 5.1.1 that procedures be developed to cover load handling operations for heavy loads that could be handled over or in proximity to irradiated fuel.
To enable proper movement of the spent fuel pit gates over irradiated fuelin the SFP, the licensee is proposing to change the existing TS to exempt the gates from the load restriction of 2500 pounds, and to institute specific administrative controls to assure that the gates 9808070337 980803 PDR ADOCK 05000338 P
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would not be dropped. The proposed TS would satisfy the guidelines in NUREG-0612 by enabling the licensee to transport the spent fuel pit gates over irradiated fuel stored in cells along the safe load path. The licensee proposed the following administrative controls to j
avoid accidents: (1) limiting the lift height of the gates; (2) attaching redundant slack-free safety cables to support the gate should crane failure occur over irradiated fuel; (3) establishing safe load paths that would result in minimum impact on the fuel if a load is dropped; and (4) enhancing the surveillance requirements to assure that the administrative controls are adequately implemented before moving the gates.
- 3. EVALUATION 3.1 TS 3 9.7 " Crane Travel - Soent Fuel Pit" Existing TS 3.9.7 requirement limiting loads exceeding 2500 pounds from travel over irradiated fuel assemblies in the SFP is changed to show that the SFP gates are exempted from this load limit. This TS limit is consistent with the design basis fuel handling accident and was established to limit any release due to a dropped load damaging all the fuel rods in a single fuel assembly. Other proposed changes to the TS add administrative controls to help assure that the SFP gates would not be dropped. The controls are as follows: (1) limits of 15 inches on the lift height of the gates above the moveable platform crane deck support beam while it is over irradiated fuel; (2) requirements that the gate be rigged to slack-free safety cables while over irradiated fuel; (3) removal of irradiated fuel with rod control cluster assemblies from the load path; and (4) removal of irradiated fuel from the cask area when the gates are lifted over the cask handling area.
Both the exemption of the SFP gates from the load limit and the addition of the administrative controls to the TS would enable the licensee to move the SFP gates over irradiated fuelin accordance with guidelines in NUREG-0612. Therefore, these changes are acceptable to the staff.
3.2 Surveillance Requirements (SRs) 4 9.7.1 and 4.9.7.2. and Bases 3/4.9.7 " Crane Travel Soent Fuel Pit" The existing SR 4.9.7.1 is changed to require that prior to moving loads over irradiated fuel, the licensee verify that the loads are less than 2500 pounds. The licensee is not required to verify the weight of the SFP gates prior to moving it over irradiated fuel. SR 4.9.7.2 is added to require that the licensee verify that the administrative controls as noted above are instituted. The proposed changes to the SR help the licensee to assure that the control measures to prevent the gates from dropping during a failure are properly implemented.
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The proposed changes to Bases 3/4.9.7, " Crane Travel-Spent Fuel Pit," justify the proposed changes to the TS. As noted in the Bases, the administrative controls on the movement of the SFP gates ensure that redundant rigging will be used to prevent a gate drop. It also ensures that the lift height of the gates would be controlled to minimize the impact if a failure resulted in a dropped gate onto stored fuel and the spent fuel pit structure.
These changes to the Bases will help to assure that the licensee will move the spent fuel pit gates in accordance with guidelines in NUREG-0612 and, therefore, are acceptable to the staff.
3.3 Load Handlina Accident Analvsis Although heavy load handling analyses are deemed not needed in Generic Letter 85-11, the licensee considered two load handling accidents to support the bases for the TS change:
(1) direct SFP gate impact on spent fuel storage cells; and (2) direct SFP gate impact on the spent fuel pit floor. According to the licensee, since these analyses are similar to the fuel handling accident antslysis, the margin of safety remains the same as the design bass accident.
Based on the analysis, the licensee found that a single failure mode between the crane and the rigging is most unlikely. The licensee also found that a gate drop would result in acceptable consequences that are bounded by the fuel handling accident analysis provided the administrative controls are properly implemented. Some fuel damage would occur; however, it would not result in a critical configuration. Also, the structural integrity of the SFP floor would not be breached. Since the gates would not be moved over the SFP transfer canals, analysis of postulated gate drops was not performed for this area.
- 4. STATE CONSULTATION in accordance with the Commission's regulations, the Virginia State official was notified of the proposed issuance of the amendments. The State official had no comment.
- 5. ENVIRONMENTAL CONSIDERATION These amendments change a requirement with respect to installation or use of a facility l-component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluent
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that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that these amendments involve no significant hazards consideration and
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4 there has been no public comment on such finding (62 FR 66146). Accordingly, these amendments meet 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 or environmental assessment need be prepared in connection with the issuance of the amendments.
- 6. CONCLUSION Based on the preceding discussions, the staff finds that the proposed changes to the TS to move the SFP gates over irradiated fuelin 'he SFP and use administrative controls to improve the handling of the gates are in accordance with NUREG-0612. These changes will enable the licensee to move the gates while preventing any damage to spent fuel and the SFP if a failure was to occur and therefore are acceptable to the staff.
l The Commission has concluded, based on the considerations discussed above, that: (1)
L 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 amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Brian E. Thomas Date:
August 3, 1998 l