ML20206C935
| ML20206C935 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 04/23/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20206C925 | List: |
| References | |
| NUDOCS 9905030255 | |
| Download: ML20206C935 (6) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION f WASHINGTON, D.C. 20M6 4001 J l
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I SAFETY EVALUATION SY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.199 TO FACILITY OPERATING LICENSE NO. NPF-1 PORTLAND GENERAL ELECTRIC EUGENE WATER AND ELECTRIC BOARD PACIFIC POWER AND LIGHT TROJAN NUCLEAR PLANT DOCKET NO. 50-344 l
1.0 INTRODUCTION
i By letter dated January 16,1997, the Portland General Electric (PGE) Company, the licensee for the Trojan Nuclear Plant (TNP) submitted a license amendment request to delete paragraph 2(C)(7) of Facility Operating License No. NPF-1 to allow pre-operational testing and handling of spent fuel transfer casks in the Trojan fuel building. This license amendment request was designated License Change Application (LCA) 240 - Movement of Cask into Fuel Building by the PGE staff. ]
l By letter dated January 16,1997, PGE submitted another license amendment request (LCA 237, Revision 1) to amend Facility Operating License No. NPF-1 to delete a license condition that prohibited movement of loaded casks in order to allow PGE to load and handle spent fuel assemblies in spent fuel casks in the fuel building. More specifically, the amendment inserted a new license condition to authorize the loading of spent fuel and other materials into transfer and storage casks in the fuel building. The licensee states that the purpose of the separate submittals was to permit pre-operational testing of the casks independent of fuel loading issues.
PGE supplemented the January 1997 letters with background information, and provided inspection and testing plans for Trojan's fuel building crane in a letter dated February 24,1997.
On April 16,1998, PGE submitted LCA 237, Revision 2, adding a new license condition to authorize PGE to load spent fuel and other materials into transfer and storage casks in the fuel building. LCA 237, Revision 2 replaced in its entirety LCA 237, Revision 1; it consisted of clarifications in the submittat due to changes in the cask design, and responses to staff requests for additional information regarding a previously issued Independent Spent Fuel Storage Installation (ISFSI) license application.
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1 LCA 237. Revision 2, consists of changes to the license condition only. An additionalletter, dated January 7,1999, provided Revision 3 to LCA 237, replacing Revision 2. Revision 3 i principally deleted reference to the loading, transfer, and storage of greater than class C {
(GTCC) waste. The existing Technical Specifications 3.1.4, Spent Fuel Pool Load Restrictions, 1 Surveillance Requirements (SRs), and Bases are unaffected by this amendment request and I will remain in effect to preclude movement of spent fuel casks over the spent fuel pool (SFP). {
PGE stated that the proposed changes of LCA 237 Revision 3 are required to facilitate continued implementation of TNP decommissioning plans. More specifically the proposed changes would allow the handling of heavy loads, including the transport of spent fuel assemblies and fuel debris in a dry storage cask system from the SFP in the fuel building to an on-site ISFSI. Once a permanent repository or other offsite storage facility becomes available, the spent fuel will be transferred to that facility.
2.0 BACKGROUND
NUREG-0612, " Control of Heavy Loads at Nuclear Power Plants," dated July 1980, provides guidelines and recommendations for licensees to assure safe handling of heavy loads by prohibiting, to the exter,t practicable, heavy load travel over spent fuel assemblies, over the core, and over safety-related equipment. The NUREG defines a heavy load as any load carried in a given area during the operation of the plant that weighs more than the combined weight of a single spent fuel assembly and its associated handling tool.
Phase i of NUREG-0612 provides guidelines for reducing the likelihood of dropping heavy loads and limiting the resulting potential consequences of a drop. The guidelines are focused on establishing safe load paths, procedures for load handling operations, training of crane operators, the design of lifting devices and the design, testing, inspection, and maintenance of cranes. Phase ll of NUREG-0612 provides guidelines for mitigating the consequences of dropped loads, including the use of a single failure proof crane, use of electricalinterlocks and mechanical stops to restrict crane travel, and performance of load drop and consequence analyses to assess the impact of dropped loads on plant safety. Generic Letter GL 85-11,
" Completion of Phase ll of Control of Heavy Loads at Nuclear Power Plants," dated June 28, 1985, dismissed the need for licensees to implement the requirements of NUREG-0612, Phase
- 11. However, via GL 85-11, licensees are encouraged to implement actions they perceive to be l appropriate to maintain safety.
PGE plans to use the TranStor Storage System to move spent fuel and other waste material from the TNP fuel building to the ISFSI. The storage system consists of seal-welded baskets l for storing the spent fuel and associated waste, ventilated concrete casks, an ISFSI storage pad, and associated transfer equipment necessary for dry storage of spent fuel assemblies, fuel debris, and associated waste. Structural support, shielding, and natural circulation cooling for the seal-welded basket is provided by the ventilated concrete cask. TNP estimates that 34 l baskets and concrete casks will be needed. Each basket is designed to store 24 PWR spent fuel assemblies and fuel debris. j Loading the seal-welded baskets into the transfer cask and then into the concrete casks is done j within the fuel building under the 10 CFR Part 50 license. The fuel building overhead crane and i a special lifting yoke are used to move the transfer cask and basket to the cask wash pit where l
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i they are examined, cleaned, and assembled. The transfer cask with the empty basket is then moved over the cask loading pit. The transfer cask and basket are decontaminated and lowered onto an impact limiter at the bottom of the cask loading pit where it is loaded with spent fuel using the fuel handling bridge crane. The gate between the SFP and the cask loading pit has to be opened to allow loading of the transfer casks. After being loaded, the transfer cask is moved from the cask loading pit in the fuel building to the top of the concrete casks at the fuel building cargo handling bay. The sealed basket is lowered from the transfer cask into the concrete cask. Subsequently, each concrete cask and loaded basket is transported from the cargo handling bay to a reinforced concrete ISFSI storage pad. An air pad system is used to lift and float each concrete cask to the ISFSt.
3.0 EVALUATION 3.1 Handling of Transfer / Storage Casks and Spent Fuel Assemblies The cask movement operation proposed by the licensee involves considerations regarding NUREG-0612. Specifically, the cask movement opcation involves handling and control of heavy loads, including the design and operation of tne fuel building hoisting system (cranes and lifting devices), movement of the seal-welded baskets and transfer casks, loading spent fuel assemblies into the sealed baskets, safe load paths, the use of procedures, crane operator and rigger training, and analyses of potential load drop accidents and consequences.
The requirements of TNP license conditions, technical specifications and administrative control procedures implement guidelines in NUREG-0612. These requirements include, among other things, prohibiting the loading of spent fuel into casks in the fuel buildirig, and restricting the movement of casks over the spent fuel pool and safety-related equipment.
The proposed modification will add a license condition to allow loading of spent fuel assemblies I and other associated materials into transfer and dry storage casks in the fuel building. An amendment dated May 19,1997, removed the license conditions that prohibited PGE from bringing spent fuel dry storage casks into the fuel building. However, the remaining license conditions and TS restrict PGE from (1) loading spent fuel into the casks, and (2) transporting the casks in proximity to and over spent fuel in the spent fuel pool. Revision 3 to LCA 237 removes the restrictions against loading spent fuel and other materials into dry storage casks.
The TS restriction against moving casks over the SFP and spent fuel assemblies is not affected
- by the proposed change and will remain in effect.
3.2 Hoisting System As stated by the licensee, the maximum load to be lifted by the fuel building crane during the transfer of spent fuel assemblies and associated wastes is approximately 108 tons. This includes the weight of the transfer cask, a loaded PWR basket, and the lifting yoke. The fuel i building 125 ton overhead crane and the transfer cask lifting yoke will be used to lift and move the transfer cask and loaded baskets from the cask loading pit to the concrete cask in the fuel l building crane bay.
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As stated in the staff's Safety Evaluation Report, dated July 18,1983, the fuel building crane is in compliance with the requirements of CMAA No. 70, " Specifications for Electric Overhe.ad Traveling Cranes," Crane Manufacturers Association of America, Inc.,1975, and ANSI B30.2-1976," Overhead and Gantry Cranes (Top Running Bridge, Multiple Girder)." The crane was manufactured by the Crane Manufacturing Service Corporation (CMSC) and installed in 1973 during plant construction. The crane has a rated load of 125 tons in the main hoist and 25 tons in the auxiliary hoist. NUREG-0612 requires the crane to be inspected, tested, and maintained according to Chapter 2-2 of ANSI B30.2-1976. Therefore, the test loads are not to exceed 125 percent of the rated load and should be applied with the crane in allits functional trave: modes. l The licensee stated that the crane was load tested at 156 tons (125 percent of the rated capacity) before initial use. To load test the crane in the transport mode, the licensee used a 125-ton load and performed the test following the original manufacturer's load test procedures.
Although ANSI B30.2 only requires a rated load test prior to initial use for all new, extensively repaired, and altered cranes, the licensee states that they will perform another rated load test prior to moving the transfer casks. This load test will help to assure that the hoisting system components are not degraded and functioning properly. The licensee indicated that the rated load tests would be performed at multiple loading conditions, including with no load, at 50 percent of the rated load if the wire rope is replaced, at the rated load, and at 125 percent of the rated load. j PGE's ISFSI Safety Analysis Report (SAR), dated December 1997, specifies that the transfer cask and trunnions, and the transfer cask lifting yoke are special lifting devices that are designed, fabricated, and tested in accordance with NUREG-0612 and ANSI N14.6-1978,
" Standard for Special Lifting Devices for Shipping Containers." The lifting yoke and slings will be interposed between the crane hook and the cask and other storage system components during the cask handling operation. The Jifting yoke is used to lift and move the transfer cask using the trunnions for support. Slings are used to lift and move the sealed basket, the basket radiation shield and structural lids, the transfer cask lid assembly, and the concrete cask shield ring and cover plate. The licensee stated that the transfer cask and trunnions are tested at 300 ;
percent of their maximum capacity and the lifting yoke is tested at 150 percent of its maximum design load in accordance with the NUREG and the code. The licensee stated that the design safety factors (load rating) of the slings, and hoist rings are consistent with criteria in NUREG-0612, Section 5.1.6(b)(ii) and 5.1.1(5) that recommends using twice the safety factors specified in ANSI B30.9-1971, " Slings."
l In addition, the licensee stated that they plan to contract CMSC to prepare a crane inspection and load testing procedure and to provide technical representatives to perform crane inspections and direct load testing activities under PGE's supervision. The crane inspections q will involve inspection of the crane, the crane rail and rail supports, a review of the load test )
procedures, rigging, safe load paths, and coordination and communication among crane 1 operators, riggers, and program managers. Various functions of the crane operation will also l be inspected including the reeving, brake operation, limit switches, speed controls, and upper {
and lower limit settings. A post load test inspection will also be performed to evaluate the integrity of the components of the lifting system prior to doing the actual cask movement. I i
The staff agrees with the licensee's conclusion that the crane coupled with the procedural and j
, administrative measures used to preclude a heavy load drop on irradiated fuel in the SFP will I assure the safety of the cask handling operation.
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1 3.3 Load Movements To reduce the potential consequences of a dropped cask the licensee plans to move the casks using high density foam impact limiters, as needed, along previously identified safe load paths.
Impact limiters will also be installed in the bottom of the cask loading pit and at the 45 foot elevation of the fuel building hoistway over the crane bay area, in addition, the licensee will use mechanical stops and electrical interlocks to limit and control crane travel. The staff agrees that these measures coupled with procedural controis will help to prevent movement of the cask over the spent fuel pool and outside the safe load paths where a load drop cou!d result in hazard in the plant.
3.4 Analysis of Postulated Load Drop Accidents !
The licensee performed analyses of postulated accident &for the cask loading and handling process, including load drops, cask tipovers, failure of components of the lifting and storage j system, and mishandling and operational events. The analyses are focused on the potential !
-consequences of these accidents when they involve criticality and radiological release. Based )
on the analyses, the licensee states that the potential consequences of a postulated drop and l tipover of the transfer cask into the cask loading pit, the cask wash pit, the fuel building i hoistway, and onto the floor in the fuel building would not result in any increases to the K,n to more than 0.95. Damage to plant equipment important to safe storage of spent fuel would not occur due, in part, to the impact limiters and steel load distribution assemblies, the physical layout of the facilities, and established safe load paths. While the transfer cask is moved over the fuel building floor at the 93 ft. elevation, the lift height is kept at 15 in. or less, and the cask is moved over floor slabi supported by rigid sheer walls and steel beams. Furthermore, impact limiters are placed at the bottom of the transfer cask as needed along the safe load path. The safe load path for the cask coupled with electricalinterlocks and mechanical stops keep cask travel away from the spent fuel pool. The staff agrees with the licensee that a dropped component would not significantly affect the safety of the operation and that the design safety factors, load testing requirements, and administrative controls for the crane and lifting devices minimize the possibility of a cask drop or tipover occurring. I Based on the above discussions, the staff Gods that the proposed change to PGE's license condition to allow loading and handling of spent fuel transfer casks is acceptable. The staff agrees with the licensee that the design safety factors, load testing requirements, and administrative controls of the lifting system are in accordance with the guidelines of NUREG-0612.
4.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Oregon State official was notified of the proposed issuance of the amendment. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
S l The amendment changes a requirement with respect to the installation or use of a facility l 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 1
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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 l FR 9197). Accordingly, the amendment meets 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 l 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 j common defense and security or to the health and safety of the public.
l Principal Contributors: Brian E. Thomas
! Lee H. Thonus
! Date: April 23,1999 l
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