ML20211M523
| ML20211M523 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 10/07/1997 |
| From: | NIAGARA MOHAWK POWER CORP. |
| To: | |
| Shared Package | |
| ML20211M519 | List: |
| References | |
| NUDOCS 9710140274 | |
| Download: ML20211M523 (10) | |
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ATTACHMENT A NIAGARA MOHAWK POWER CORPORATION LICENSE NO NPF.69 DOCKET ido. 50 410 Pronosed Channes to Technical Specificatione Replace existing page 3/4 9 8 with the attached revised page. This page has been retyped in its entirety with rnarginal markings to indicate changes to the text.
9710140274 971007 PDR ADOCK 05000410 P PDH
REFUELING. OPERATIONS 3)4.B.8 REFUELING PLATFORM l
LIMITING CONDITIONS FOR OPERATION 3.9.6 The refueling platform shall be OPERABLE and used for handling fuel assemblies or i control rods within the reactor pressure vessel.
APPLICABILITY: During handling of fuel assembliet or control rods within the reactor pressure vessel.
ACTION:
With the requirements for refueling platform OPERABILITY not satisfied, suspend use of any inoperable refueling platform equipment from operations involving the handling of _ q 3
control rods and fuel assemblies within the reactor pressure vessel after placing the load in a safe condition. {
i SURVEILLANCE REQUIREMENTS 4.9.6 Each refueling platform crane or hoist used for handling of control rods or fuel assemblies within the reactor pressure vessel shall be demonstrated OPERABLE within 7 days before the start of such operations with that crane or hoist by:
- a. Demonstrating operation of the overload cutoff on the main hoist when the load exceeds 1600 +100/ 0 pounds, i
- b. Demonstrating operation of the overload cutoff on the frame mounted and monorail mounted auxiliary hoists when the load exceeds 1000
- 50 pounds,
- c. Demonstrating operation of the main and auxillery hoist uptravel stops when the grapple is lower than or equal to 7 feet 3 3/4 inches below the platform tracks.
- d. Demonstrating operation of the downtravel mechanical cutoff on the main hoist when grapple book down travel reaches 4 inches below fuel assembly handle.
- e. Demonstrating operation of the slack cable cutoff on the main hoist when the load is less than 50 *-10 pounds.
- f. Demonstrating operation of the loaded interlock on the main hoist when the load exceeds 700 +50/ 0 pounds.
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- g. Demonstrating operation of the redundant loaded interlock on the main hoist when the load exceeds 700 + 50/ 0 pounds.
1 NINE MILE POINT - UNIT 2 3/4 9 8 Amendment No. Id l
ATTACHMENT 5 NIAGARA MOHAWK POWER CORPORATION j LICENSE NO. NPF 89 '
DOCKET NO, 50 410 Sunnotting information and No Blanificant Hazards Co. mi.. A.-deelm
[tGEODUCTION Nine Mile Point Unit 2 (NMP2) Technical Specifications (TS) Section 4.g.6 lists the Surveillance Requirements (SRs) for the refueling platform crane or hoist and provides the appropriate setpoints foi the various functions.
The proposed TS change revises TS SRs 4.g.6 a,4.g.6.f, and 4.g 6.g to specify the refueling platform fuel grapple hoist setpoints that correspond with the use of a General Electric Model NF 500 refueling mast. Niagara Mohawk plans to install and utilize the Model NF 500 mast as the refueling platform fuel grapple hoist during the next NMP2 refueling outage. The hoist is used inside the Reactor Building for reactor core refueling operations.
The fuel grapple hoist currently consists of a four segment, open frame, triangular mast.
The Model NF 500 is a four segment, solid, cylindrical telnscoping mast and includes a new grapple head equipped with a camera /TV system.
The round mast is structurally stronger than the triangular mast and is less susceptible to damage during fuel moves. The cameraRV system will enhance visibility for fuel handling activities and will provide additional assurance that the grapple is oriented over the correct fuel bundle.
The round mast with a camera 6V system is essentially a direct replacement for the existing triangular mast. The applicable standards, codes ano design criteria will continue to be met and the new mast will function like the existing one. The only difference is in the weight of the two masts. The round mast weighs approximately 400 lbs more than the triangular mast. The NMP2 TS SR setpoint changes are being proposed for the purpose of compensating for the increased weight of the new mast sections. The basis for the requirements remain unchanged and the required functions will still be tested.
ANALYSIS The TS LCO requirement states the refueling platform shall be operable and used for handling fuel assemblies or control rods within the reactor pressure vessel. The TS Bases states that the OPERABILITY requirements ensure that (1) the refueling platform will be used for handling control rods and fuel assemblies within the reactor pressure vessel, (2) each crane and hoist has sufficient load capacity for handling fuel assemblies and control rods, and (3) the core internals and pressure vessel are protected from excessive lifting force in the event they are inadvertently engaged during lifting operations. The new mest with cameraRV system is a direct replacernent for the existing mast. The ability of the Page 1 of 6
refueling platform to perform its design function is not affected by the addition of the round mast and cameraRV system.
TS SRs 4.9.6.a 4.9.6.f, and 4.9.6.g must bo changed to accommodato the new round !
mast and camera /TV system. The setpoints that must be increased to compensate for the
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added wolght of the nr w mast and cameraRV aystem are all related to the main hoist and j are the overload cuton, loaded Interlock and redundant loaded interlock. '
The hoist overload cut iff sotpoint is selected to limit the lifting forces of the hoist to ensure excessive lift 5; forcos are not applied to a fuel bundle should it become stuck during lifting operatirsis. The overload cutoff also protects other core and reactor vessel l components from damage should they be inadvertently engaged during lifting operations.
The most limiting component is the fuel bundle, which is designed to withstand an upward handling load equivalent to 3 times the weight of the fuel bundle (3g). This load is defined as 2g Ilft, plus 1g of fuel assembly weight, or approximately 2,000 lbs. The new proposed holst overload sotpoint is 1600 + 100/ O lbs., which is substantially below the 2,000 lb.
limiting force for the fuel bundles.
l The holst loaded and redundant loaded interlocks are actuated when the main holst is loaded with a fuel bundle. They operate independently and perform different functions.
l The hoist loadod interlock initiatos a control rod block to prohibit control rod withdrawal I
when the main hoist is loaded and located over the reactor vessel, or conversely, prevents lifting a load when the main holst is over the reactor vossol and a control rod is withdrawn.
The redundant loaded interlock initiates a bridge reverse block to provent movement of the refueling platform toward the core when tiw main hoist is loaded and a control rod is withdrawn. It is assumed that the hoisted load is a fuel bundle, since this is the most limiting load that could potentially be dropped. Th6 minimum submerged cable weight of the round mast is approximately 160 lbs. The submerged */;&!ght of a channeled fuel bundle is approximately 650 lbs. Therefore, the proposed hoist loaded and redundant loaded interlock sotpoints of 700 + 50/ 0 lbs. will still ensure that the associated interlocks will be initiated when the weight of a channeled fuel bundle is applied to the grapple.
Additionally, the maximum cable weight of the round mast fully retracted or at the overhoist position is approximately 570 lbs. Thorofore, the loaded interlock setpoints must be sufficiently above this weight to ensure that a "falso" hoist loadod signal does not hamper refueling activitios. The proposed now sotpoint of 700 + 50/-0 lbs. maintains this basis.
The setpoints for both the hoist loaded and redundant loaded interlocks will be sot at the same value for consistency with vendor recommendations. Historically, both interlocks have boon actuated simultaneously when a fuel bundle is hoisted. Thero is no specific basis for the differences in those two setpobts. Moving the redundant loaded interlock sotpoint to 700 lbs. is conservative with respect to the increased wolght of the new mast and minimizes any possible confusion with having two separate setpoints, in addition, the sotpoint tolerances for the survoillances have also boon revised for consistency with vendor recommendations. This will more accurately reflect the design function of ensuring the interlocks actuato at a specified minimum weight.
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A Interlocks between the reactor modo switch and the refueling platform are provided to ensure that restrictions on refueling platform movement during refueling operations are -
properly activated. The hoist loaded and redundant loaded interlocks can initiate a control rod block or prevent the movement of the refueling platform toward the core if conditions warrant. These interlocks will remain functionally unchanged by this modification.
Updated Safety Analysis Report (USAR) Section 9.1.4 requires the working loads of the refueling platform structures to be in accordance with the American institute of Steel Construction (AISC) Manual of Steel Construction. The USAR also states that all parts of the hoist systems are designed to have a minimum safety factor of 5 based on the ultimate strength of the material. In addition, a redundant load path must be incorporated in the fuel hoists so that no single component failure could result in a fuel bundle drop. The round mest and camera /TV system were constructed to the same standards and specifications as the triangular mast, therefore, these existing requirements will be met.
The seismic analysis of the refueling platform was redone to verify the Safe Shutdown Earthquake (SSE) criteria of the USAR were met. The re analysis was necessary to qualify the refueling platform _with_the additional weight of the round mast, TV grapple head system, and associated equipment, to prevent structural collapse and damage to fuel, reactor vessel components or the fuel storage racks. This re analysis confirmed the refueling platform met the SSE criteria.
The USAR discusses requirements for the refuel mast and grapple height to ensure that a fuel assembly is not raised above the point where adequate water shielding is available.
The round mast uptravel stop and downtravel mechanical cutoff setpoints are not being changed and will continue to ensure minimum water shielding is maintained. In addition, the existing digital display system for grapple position indication and instrumentation for grapple alignment and orientation will be used with the new mast and will function the same. The new mast will also have the same redundancy regarding interlocks and limit switches as the current mast.
10CFR50 Appendix A General Design Criteria for Nuclear Power Plants Criterion 2, requires structures, systems, and components important to safety to be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, etc. without loss of capability to perform their safety function. The refuel mast satisfies the requirements of GDC 2 as it relates to the protection of safety related equipment and spent fuel from the effects of earthquakes. This is described in NUREG 1047, NMP2 SER Section 9.1.4.
The mast is mounted on the refueling platform which is housed within the reactor building and the secondary containment, which are seismic Category 1, flood and tornado protected. The reactor building roof decking may be affected by a tomado, but any potentially damaged decking witt not affect other safety related structures. The refueling platform is des!gned to Seismic Category I criteria so that it will not fail in a mannar which results in unacceptable consequences, such as fuel damage or damage to safety related equipment. As described above, the seismic qualification of the refueling platform was re-analyzed to include the additional weight of the new mast and camera /TV system, and the results were determined to be acceptable.
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General Design Criterion 61 and 62 are concerned with the prevention of unacceptable radioactivity releases and criticality accidents. The existing triangular mast was determined to meet the requirements of Criterion 61 and 62 per NUREG 1047, NMP2 SER Section 9.1.4. The new round mast is essentially a direct replacement for the triangular mast. It has been constructed to the same standards, meets the same design criteria and functions the same as the triangular mast. Therefore, the round mast will also meet the requirements of GDC 61 and 62.
NUREG 0800 Standard Review Plan, Section 9.1.4, requires the system and its components to conform to the relevant requirements of General Design Criterion 2,61 and i
- 62. As determined in the preceding paragraphs, the new mast satisfies the relevant requiraments of GDC 2,61, and 62.
The use of GE11 (9X9) fuel bundles, as well as 8x8 fuel bundles, have been evaluated for l use with the new mast and camera /TV system. USAR Section 15.7.4, Fuel Handling Accident, will be revised to include the additional weight of the new mast and camera /TV system. The mathematical modelin USAR Section 15.7.4 will utilize the same criteria as the current revision of the General Electric GE3 TAR ll document (NEDE 24011 P A 11 U5).
The current GESTAR ll document uses a lower threshold level for fuel rod damage. The new threshold for damage is 200 ft. lb. for the 9x9 fuel bundles as opposed to 250 ft. lb.
currently being utilized for the 8x8 fuel bundles. Using the GESTAR ll criteria and the added weight of the new mast and cameranV system with the 9X9 fuel bundle, the total number of damaged fuel rods derived from the mathematical modelis 140. The total number of dr.maged fuel rods currently analyzed in the USAR is 124. A calculation was performed to determine the radiological consequences caused by the additional 16 damaged rods. Based on the GE11 bundle design and the fact that the same activity is spread over a larger number of rods within the fuel bundle, there is no increase in the radiological consequences as compared with that for the currently analyzed fuel bundles.
The calculation confirms that the radiological consequences are still well within the GDC 19 and 10CFR100 limits.
CONCLUSIONS The new NF 500 round mast with a camera /TV system is essentially a direct replacement for the existing triangular mast. The applicable standards, codes and design criteria will continue to be met and the new mast will function like the existing one. The only difference is in the weight of the two masts. The round mast weighs approximately 400 lbs more than the triangular mast. The TS SR setpoint changes are being made for the purpose of compensating for the increased weight of the new mast sections. The basis for the requirements remain unchanged and the required functions will still be tested.
The new camera /TV system will actually provide enhanced visibility for fuel handling activities and adoitional assurance that the grapple is oriented over the correct fuel bundle, it should be noted that the camerafrV system is an enhancement and that failure of the camera /TV system will not preclude continued refueling activities.
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HQ_SIGNIFICANT HAZARD _S CONSIDERATIOfLANALYSIS 10CFR50.91 requires that at the time a licensee requests an amendment, it must provide to the Commission its analysis, using the standards in 10CFR50.92 concerning the issue of no significant hazards consideration. Therefore, in accordance with 10CFR50.91, the following analysis has been performed with respect to the requested change.
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Ittg_pantation of Nine Mile Pojnt Unit 2. In accordence with the orooosed amendment will not involve a slanificant increase in the orobability or cQDMauences of an accident l previously evaluated.
The proposed change revises the setpoints for three TS SRs based on modifications to the refueling platform mast. The new most is essentially a direct replacement for the existing mast, with the exception that the new mast is approximately 400 lbs. heavier, which directly affects the setpoints. No change in the frequency or manner in which the surveillances are performed is proposed. Refueling interlocks will continue to function as designed. No changes to the methods in which plant systems are operated are required.
The same design criteria and standards were applied to the new mast, including the seismic capability of the refueling platform with the heavier mast. Therefore, none of the precursors of previously evaluated accidents are affected, and no new failure modes are ir.troduced.
Based on the additional weight of the new mast and camera /TV system, the revised GESTAR criteria for fuel rod damage (more conservative threshold level), and the use of GE11 fuel for the bundle drop analysis, the number of damaged fuel rods has increased slightly for the potential fuel handling accident. The results of this increase were evaluated i
and dispositioned against the bounding calculation to show that the current USAR analysis '
bounds the revised radiological consequences which remain well within the GDC 19 and 10CFR100 limits. The systems that are available to mitigate the consequences of any accident have not been affected and are still capable of performing their required functions.
Therefore, this change will not involve a significant increase in the probability or consequences of an accident previously evaluated.
The operation.of Nine Mile Point Unit 2. In accordance with the oronosed amendment, will not create the nossibility of a new or different kind of accident from any accident oreviousiv evaluated.
The proposed change revises the setpoints for three TS SRs based on installation of a new refueling platform mest which is heavier than the current mast No change in the frequency or manner in which the surveillances are performed has occurred. Refueling interlocks will continue to function as designed. No changes to the methods in which plant systems are operated are required. The same design criteria and standards were applied to the new mast, including the seismic capability of the refueling platform with the heavier mast, The basic function and operation of the refueling platform is unchanged. The uptravel stop and downtravel mechanical cutoff setpoints are not being changed and will continue to ensuro that adequate water shielding is maintained. As such, the change does not introduce any new failure modes or conditions that may create a new or different kind
' of accident. Therefore, this change will not create the possibility of a new or different kind of accident from any accident previously evaluated.
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The eneration of Nine Mile Point Unit 2. In anordance with the nronosed amendment, wl4 not involve a slanificant reduction in a marnin of safety.
The proposed change revises three TS SR setpoints based on installation of a new refueling platform mast. No change in the frequency or manner in which the surveillances tre performed has occurred. Refueling interlocks will continue to function as designed. No changes to the methods in which plant systems are operated are required. The same design criteria and standards were applied to the new mast, including the seismic capability of the refueling platform with the heavier mast. The addition of a cameraflY system will provide enhanced visibility for fuel handling activities and additional assurance that the grapple is oriented over the correct fuel bundle.
The additional weight of the new mast has been evaluated and the operability requirements as describert in the TS and TS Bases are unchanged. The modification and revised setpoints do not change the function of the refueling platform main holst. The revised
! setpoints will continue to assure the lif ting capacity of the main hoist will not be sufficient to result in damage to core Internals or the reactor pressure vesselin the event that they are accidentally engaged.
The necessary systems are still available to mitigate any potential radiological consequences of the increased number of damaged fuel rods. The radiological consequences remain within the bounds of the current safety analysis and well below the GDC 19 and 10CFR100 limits. Therefore, the change does not involve any significant reduction in a margin of safety.
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ATTACHMENT C NIAGARA MOHAWK POWER CORPORATION LICENSE NO. NPF 69 DOCKET NO. 50 410 The current version of NMP2 Technical Specifications page 3/4 9 8 has been hand marked-up to reflect the proposed change.
i prutLING OFFJtATIONS
. 3/4,9,6 REFUttfNG PLATFORM LIMITING CONDITIONS FOR OPERATION 3.9.6 The refueling platform shall be OPERABLE and used for handling fuel assemblies or control rods within the reactor pressure vessel.
APPLICABILITY: During handling of fuel assemblies or control rods within the reactor pressure vessel.
ACTION:
Vith the requirements for refueling platform OPERABILITY not satisfied, suspend use of any inoperable refueling platform equipment from operations involving the handling of control rods and fuel assemblies within the reactor pressure vessel after placing the load ir a safe condition.
SURVEIf f ANCE REQUIREMENTS 4.9.6 Each refueling platform crane or hoist used for handling of control rods or fuel assemblies within the reactor pressure vessel shall be demonstrated OPERABLE within 7 days before the start of such operations with that crane or hoist by: .
- a. Demonstrating oper tion f the overload cutoff on the main hoist when the load exceeds pounds. !
/&oo+t06/-o
- b. Demonstrating operat o the overload cutoff on the frame mounted and monorail mounted auxiliary hoists when the load exceeds 1000 1 50 pounds.
- c. Pr.nonstrating operation of the main and auxiliary hoist uptravel stops when the grapple is lower than or equal to 7 feet 3 3/4 inches below the platform tracks. i
- d. Demonstrating operation of the downtravel mechanical cutoff on the main hoist when grapple hook down travel reaches 4 inches belov fuel assembly handle.
- e. Demonstrating operation of the slack cable cutoff on the main hoist when the load is less than 50 1 10 pounds.
- f. Demonstrating oper t f the loaded interlock on the main hoist 5.nen the load exceeds 43 50 ounds. l 7oo t ro/-o
- g. Demonstrating operatioin o t undant loaded interlock on thu main hoist when the load exceedsc. 0 2 Sv pounds. l f 07 c + A/- o NINE HILE POINT - UNIT 2 3/4 9-8 AmendmentNo./f i
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