ML20057C183
| ML20057C183 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/21/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20057C181 | List: |
| References | |
| NUDOCS 9309280045 | |
| Download: ML20057C183 (7) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION O
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....f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0.159 TO FACILITY OPERATING LICENSE NO. DPR-20 CONSUMERS POWER COMPANY PALISADES PLANT DOCKET NO. 50-255
1.0 INTRODUCTION
By letter of January 29, 1993 (Ref. 1), Consumers Power Company (CPCo), the licensee, submitted a request to amend the Palisades Nuclear Plant Technical Specifications (TSs) to Facility Operating License D'R-20 to change the radiat peaking factor limits for the planned Cycle 11 operation. The staff reviewed the impact of the proposed changes on the Chapter 15 accident analyses and found the changes acceptable. TS Amendment 156 was issued on June 16, 1993.
During the subsequent refueling outage, a failed fuel rod was discovered in a peripheral assembly that was scheduled for Cycle 11 operation.
Further inspection was performed on other assemblies from this reload batch, which had achieved five operating cycles, with the last two on the core periphery.
Based on results of this inspection program, CPCo evaluations using new selection criteria led to a core configuration redesign, using a later fuel batch design with only three operating cycles. Reanalysis of the Chapter 15 events confirmed the acceptability of the approved radial peaking factor limits for the revised Cycle 11 core design. CPCo performed a 10 CFR 50.59 evaluation of the revised Cycle 11 core design, which was reviewed by the NRC staff during an inspection trip on August 19-21, 1993.
By letter of September 3,1993 (Ref. 2), CPCo submitted an additional TS change request to clarify the application of the previously approved peaking limits to the newly reconstituted fuel batch.
The proposed amendment would change Table 3.23-2, Radial Peaking Factor Limits, to include limits for the new revised "L" fuel assemblies installed during the 1993 refueling outage, and to delete reference to the "1" fuel assemblies containing 208 fuel rods that are not to be used in Cycle II.
In addition, the unnecessary references of the number of fuel rods in each assembly type in Table 3.23-2 and Table 3.23-1 would be deleted.
The bases for several TSs (2.1, 2.3, 3.1, 3.12, and 3.23.2) have been updated to reflect the revision of the analytical reports for Cycle 11.
2.0 EVALUATION The safety analyses for the revised Palisades Cycle 11 core operation are provided in Siemens Power Corporation (SPC) reports EMF-92-177, Revision 2 (Ref. 3) and EMF-92-178, Revision 1 (Ref. 4). The first report describes the revised core design and the safety evaluation of the changes to the core 9309280045 930921 ADOCKOSOOg5 DR
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- neutronics and thermal-hydraulic characteristics. Cycle 11 includes three reload batches of SPC fuel with high thermal performance (HTP) grid spacers (Reload Batches M, N, and 0).
Eight Reload Batch N partial shielding assemblies (SAN), first loaded in Cycle 9, were reinserted along with the sixteen newly reconstituted Reload Batch L assemblies in low power peripheral locations to reduce vessel weld fluence. The physics characteristics evaluated include power distribution, control rod reactivity, and moderator temperature coefficient (MTC) considerations. The core loading configuration 1
was optimized by SPC to remain within the approved TS limits of:
Assembly Radial Peaking Factor (F/) limits of 1.76 (Batch 0),1.66 (Batch N), 1.57 (Batches M and L)
Total Radial Peaking Factor (F/) limits of 2.04 (B.atch 0),1.92 (all others)
Linear Heat Generation Rate (LHGR) limit of 15.28 kw/ft to 60% of core height; linearly decreasing to 14.21 kw/ft at 100% core height The maximum calculated values for the limiting Batch 0 assembly F/ and F/
were 1.575 and 1.851, respectively; which, when combined with the TS uncertainties, are within the TS power peaking limits. The largest calculated LHGR is 11.63 kw/ft which is also within the TS limiting value with the TS uncertainty included.
Shutdown margin calculations were performed for the modified Cycle 11 configuration, yielding a cycle minimum shutdown margin of 2.56% delta-rho at end of cycle (E0C), hot full power (HFP) conditions, which is above the TS limit of 2.00.
The MTC was evaluated for the revised Cycle 11 core configuration at both hot zero power (HZP) and HFP for beginning of cycle (BOC) and E0C conditions. The calculated MTC values are within the safety analysis limits of +0.5x10 delta-rho / degrees F and -3.5x10 delta-rho / degrees F.
Report EMF-92-178, Revision 1, documents the disposition and analysis of the Palisades Final Safety Analysis Report (FSAR) Chapter 14 events in support of Cycle 11 operation. The events were evaluated in accordance with Chapter 15 of the Standard Review Plan (SRP) and used approved SPC methodologies.
SPC reviewed the previous SRP Chapter 15 analyses and reanalyzed the eight events affected by tha Cycle 11 redesign:
Increase In Heat Removal by the Secondary System 15.1.3 Increase in Steam Flow Decrease in Reactor Coolant System Flow 15.3.1 Loss of Forced Reactor Coolant Flow 15.3.3 Reactor Coolant Pump Rotor Seizure Reactivity and Power Distribution Anomalies 15.4.2 Uncontrolled Control Rod Bank Withdrawal at Power Operation Conditions
15.4.3 Control Rod Misoperation (la) Dropped Control Rod (Ib) Dropped Control Rod Bank (5) Single Control Rod Withdrawal Decreases in Reactor Coolant Inventory 15.6.1 Inadvertent Opening of a PWR Pressurizer Pressure Relief Valve The minimum departure from nucleate boiling ratio (MDNBR) evaluation for the revised Cycle 11 core configuration was performed with the ANFP CHF correlation for the TS limiting radial peaking factor values. The reanalysis of eight SRP Chapter 15 events, as reported in EMF-92-178, Revision 1, shows that calculated DNB margins are improved with the exceptio'n of Events 15.4.2 -
Uncontrolled control rod bank withdrawal at power,15.4.3(5) - Control rod misoperation: single rod withdrawal, and 15.6.1 - Inadvertent opening of pressure relief valve, which show a slight DNB margin degradation. All event; acceptance criteria, however, are met for the revised Cycle 11 core.
Since the design criteria were met for the redesign, the licensee proposes to change Table 3.23-1 Linear Heat Rate Limits and Table 3.23-2 Radial Peaking Factor Limits only to clarify the application of the previously approved limits to the revised Cycle 11 core design reload batches.
3.0 CONCLUSION
The licensee and SPC performed a redesign of the Palisades Cycle 11 core and completed the required reanalysis to demonstrate that the radial peaking factor limits would not be exceeded.
The staff has reviewed the submittal and has concluded that the previously approved Cycle 11 radial peaking factors limits are acceptable with the added clarification to Tables 3.23-1 and 3.23-2.
4.0 EMERGENCY CIRCUMSTANCES In its September 3,1993, application, the licensee requested that the amendment request be treated as an emergency amendment because the changes to the TS controls are needed prior to Palisades startup and reaching 25% of rated power which in the present schedule would be September 22, 1993, the day the plant would be returned on-line.
In accordance with 10 CFR 50.91(a)(5), the licensee has provided information that the need for the emergency arose as a result of information obtained over the past few weeks during the investigation and evaluation of Palisades' fuel handling events and the plan to reconfigure the reactor core. This plan included a selection criteria and appropriate justification and was provided to the NRC in CPCo's August 16, 1993, reply to NRC's request for additional information and in CPCo's revised Cycle 11 core design 10 CFR 50.59 evaluation. The 50.59 evaluation had been reviewed by the NRC staff during its August 19-21, 1993, inspection.
In the exit meeting following the inspection, the NRC suggested that changes be made to clarify the TS with
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. regard to the peaking factor limits for the reconstituted "L" fuel assemblies in Table 3.23-2.
Further review by the NRC resulted in the determination that appropriate TS controls would be necessary prior to startup and reaching 25%
of rated power.
CPCo's review of the potential need for a TS amendment had recognized that no safety significance existed with the peaking factors associated with the "L" fuel assemblies which are located in the core periphery. However, the licensee failed to consider that even though the "L" fuel was located in a low power region of the core, there were no specific peaking factor limits identified for these reconstituted fuel assemblies listed in the TS. Once the l
need for the TS amendment was confirmed by the NRC, CPCo immediately compiled l
the necessary documentation for the TS amendment request.
Failure to have an approved TS amendment in place by the time the plant is returned on-line would prevent the plant from returning to power operation.
Accordingly, the Commission has determined that there are emergency circumstances warranting l
prompt approval by the Commission pursuant to 10 CFR 50.91(a)(5).
j l
5.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION
DETERMINATION l
The Commission's regulations in 10 CFR 50.92(c) state that the Commission may make a final determination that a license amendment involves no significant hazards consideration if operation of the facility in accordance with the amendment would not:
(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.
I The proposed changes do not involve a significant hazards consideration because the operation of the Palisades Plant in accordance with the proposed changes would not:
(1) Involve a sianificant increase in the probability or conseauences of an accident previously evaluated.
The radial peaking factor limits for 208 fuel rod assemblies are being removed and the limits for Reload L fuel assemblies are being reinserted.
Sixteen Reload L assemblies that have been reconstituted with fourteen stainless steel pins in corner positions are being used in the Cycle 11 core design.
The Reload L assemblies are replacing Reload I hafnium assemblies that were part of the original Cycle 11 core design. This change is in core neutronics parameters due to changes in the fuel design and fuel management scheme. No changes to plant hardware (other than the new fuel and reconstituted Reload L fuel assemblies) are involved.
There are no associated changes in plant systems operating procedures or in instrument trip settings. Operation of the facility in accordance with the proposed TS would, therefore, have no effect on the way the plant
systems are operated, or the way these systems would respond to postulated events.
The increased radial peaking limits for Cycle 11 caused the' predicted MDNBR to decrease and peak linear heat rate to increase for several anticipated operational occurrences (A00s). Tha MDNBR is predicted to remain above the ANFP correlation limit and the peak linear heat rate is predicted to remain below the fuel centerline melt criteria for all A00 '
events.
Therefore, the consequences of all A00 events are within the specified acceptable fuel design limits.
Several postulated accidents were not bounded by the previous analyses.
The licensee analyzed the effect of increased radial peaking limits on MDNBR and peak linear heat rate for the reactor coolan.t pump rotor seizure and single rod withdrawal events. The MDNBR for the reactor coolant pump rotor seizure and single rod withdrawal events is predicted to remain above the ANFP correlation limit and the peak linear heat rate is predicted to remain below the fuel centerline melt criteria.
The license also assessed the effect of increased radial peaking limits on radiological consequences for the fuel handling and spent fuel cask drop accidents. The predicted radiological consequences for the fuel handling and spent fuel cask drop accidents are less than those predicted by the previous analyses of record. Though higher peaking factors are allowed, the use of dose conversion factors from ICRP 30, which are consistent with the latest revision to 10 CFR Part 20, results ?n lower predicted consequences.
Therefore, the NRC staff concludes that the consequences of all events remain below those calculated in the acceptance criteria and operation of Palisades in accordance with the proposed TS would not result in a significant increase in the probability or consequences of an accident previously evaluated.
(2) Create the possibility of a new or different kind of accident from any accident previously evaluated.
The radial peaking factor limits for 208 fuel rod assemblies are being removed and the limits for Reload L fuel assemblies are being reinserted.
Sixteen Reload L assemblies that have been reconstituted with fourteen stainless steel pins in corner positions are being used in the Cycle 11 core design. This change is in core neutronics parameters due to changes in the fuel design and fuel management scheme. No changes to plant hardware (other than the new fuel and reconstituted Reload L assemblies) are involved. There are no associated changes in plant systems operating procedures or in instrument alarm or trip settings. Therefore, the NRC staff concludes that operation of Palisades in accordance with the proposed TS would not create the possibility of a new or different kind of accident from any previously evaluated.
'4
' (3) Involve a sianificant reduction in a marain of safety.
The radial peaking factor limits for 208 fuel rod assemblies are being removed and the limits for Reload L fuel assemblies are being reinserted.
Sixteen Reload L assemblies that have been reconstituted with fourteen stainless steel pins in corner positions are being used in the Cycle 11 core design. The increased radial peaking limits for Cycle 11 caused the predicted MDNBR to decrease and peak linear heat rate to increase for several A00s. The MDNBR is predicted to remain above the ANFP correlation limit and the peak linear heat rate is predicted to remain below the fuel centerline melt criteria for all A00 events. Therefore, the consequences of all A00 events are within the specified acceptable fuel design limits.
Several postulated accidents were not bounded by the previous analyses.
The licensee analyzed the effect of increased radial peaking limits on MDNBR and peak linear heat rate for the reactor coolant pump rotor seizure and single rod withdrawal events. The MDNBR for the reactor coolant pump',
rotor seizure and single rod withdrawal events is predicted to remain above the ANFP correlation limit and the peak linear heat rate is predicted to remain below the fuel centerline melt criteria.
The license also assessed the effect of increased radial peaking limits on radiological consequences for the fuel handling and spent fuel cask drop accidents. The predicted radiological consequences for the fuel handling and spent fuel cask drop accidents are less than those predicted by the previous analyses of record. Though higher peaking factors are allowed, the use of dose conversion factors from ICRP 30, which are consistent with the latest revision to 10 CFR Part 20, results in lower predicted consequences.
Therefore, the NRC staff concludes that operation of Palisades in accordance with the proposed TS would not involve a significant reduction in a margin of safety.
6.0 STATE CONSULTATION
In accordance with the Connission's regulations, the Michigan State Official was notified of the proposed issuance of the amendment. The Michigan State Official had no comments.
7.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The 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 Commission has made a final no significant hazards consideration determination with respect to this amendment. 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
r
. I or environmental assessment need be prepared in connection with the issuance of the amendment.
8.0 CONCLUSION
The staff 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.
9.0 REFERENCES
1.
Letter from G.B. Slade, CPCo, to U.S. NRC, " Palisades Plant - Technical Specifications Change Request - Radial Peaking Factor Limits for Cycle 11," dated January 29, 1993.
2.
Letter from G. B. Slade, CPCo, to U.S. NRC, " Palisades Plant - Technical Specification Change Request - Revision to Radial Peaking Factor Limits for Cycle 11," dated September 3,1993.
3.
EMF-92-177, Revision 2, " Palisades Cycle 11 Safety Analysis Report,"
Siemens Power Corporation, dated August 17, 1993.
4.
EMF-92-178, Revision 1, " Palisades Cycle 11: Disposition and Analysis of Standard Review Plan Chapter 15 Events," Siemens Power Corporation, dated August 23, 1993.
Principal Contributor:
E. D. Kendrick Date:
September 21, 1993 i
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