ML20029D666
| ML20029D666 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 05/04/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20029D662 | List: |
| References | |
| NUDOCS 9405090210 | |
| Download: ML20029D666 (4) | |
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UNITED STATES g'UC[ !
i NUCLEAR REGULATORY COMMISSION e
WASHINGTON, D.C. 20555-0001 gv j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ON REVISED EMERGENCY ACTION LEVELS CONTAINED IN CALLAWAY PLANT EMERGENCY PLAN UNION ELECTRIC COMPANY CALLAWAY PLANT DOCKET N0 50-483
1.0 INTRODUCTION
By letter dated December 17, 1993, as supplemented by letters dated April 21 and 25, 1994, Union Electric Company (the licensee) requested changes to the i
Callaway Plant emergency classification procedure.
Specifically, Revision 15 to EIP-ZZ-00101, " Classification of Emergencies," incorporated revised emergency action levels (EALs) based upon NUMARC/NESP-007, " Methodology for i
Development of Emergency Action Levels," (Revision 2, January 1992). The NRC endorsed NUMARC/NESP-007 in Regulatory Guide 1.101, " Emergency Planning and Preparedness for Nuclear Power Reactors," (Revision 3, August 1992).
The regulatory guide provides an acceptable method for developing EAls as required in Section IV.B of Appendix E to Part 50, of Title 10 of the Code of Federal Reaulations.
2.0 EVALUATION The proposed EAL changes were reviewed against the requirements in 10 CFR 50.47(b)(4) and Appendix E to 10 CFR Part 50.
Section 50.47(b)(4) specifies that onsite emergency plans must meet the following standard:
"A standard i
emergency classification and action level scheme, the bases of which include facility system and effluent parameters, is in use by the nuclear facility licensee..."
Section IV.C. of Appendix E to 10 CFR Part 50 specifies that " Emergency action levels (based not only on onsite and offsite radiation monitoring information J
but also on readings from a number of sensors that indicate a potential emergency, such as pressure in containment and the response of the Emergency Core Cooling System) for notification of offsite agencies shall be described...The emergency classes defined shall include: (1) notification of unusual event, (2) alert, (3) site area emergency, and (4) general emergency."
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In Revision 3 to ' Regulatory Guide 1.101, " Emergency Planning and Preparedness for Nuclear Power Reactors," the staff endorsed NUMARC/NESP-007, Revision 2,
" Methodology for Development of Emergency Action Levels," as an acceptable method for developing EAls as required in 10 CFR 50.47(b)(4) and Appendix E to 10 CFR Part 50. The staff relied upon the guidance in NUMARC/NESP-007 as the basis for its ' review of Callaway Plant's EAL changes:
9405090210 940504 PDR ADOCK 05000483 p
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. The licensee organized the EAls into four groups relating to indications of specific emergency classifications.
Group 1 corresponds to Abnormal Radiation Events, with associated matrices provided for Offsite Events and Onsite Events.
Group 2 corresponds to Fission Product Barriers.
Group 3 corresponds to Hazards Affecting Plant Safety, with associated matrices provided for Security Events, Fires, Natural Events, Toxic Gas, and Control Room Evacuation Events.
Group 4 corresponds to System Malfunctions, with associated matrices provided for Annunciator Events, Electrical Events (Operating), Electrical Events (Shutdown), Shutdown Capability, Communication Events, RCS/ Fuel Events l
and Reactor Protection System.
Most of the proposed EAls conform closely to the guidance; however, several of the licensee's proposed changes differ from the EAls examples provided in NUMARC/NESP-007.
The staff review of these variations, as discussed below, determined that the licensee's justification was acceptable.
Two EALs were determined to have site-specific setpoints which are overly conservative, l
i.e., the setpoints are too low.
The interim acceptability of theso EALs, until the setpoints can be recalculated, is also discussed below.
1.
Emergency Coordinator Judgement EAL The licensee's EAL scheme deviates from the NUMARC/NESP-007 guidance by not including EAls for classifying events, based upon the Emergency Coordinator's judgement. The licensee opted to include specific guidance as to what conditions warrant declaration of an event, based upon the Emergency Coordinator's judgement, in the body of emergency classification procedure instead of in an EAL.
This deviation from the NUMARC/NESP-007 guidance is acceptable.
2.
Containment Pressure EAL for the Potential Loss of Containment NUMARC/NESP-007, Table 4, PWR EMERGENCY ACTION LEVEL FISSION PRODUCT BARRIER REFERENCE TABLE THRESH 0LDS FOR LOSS OR POTENTIAL LOSS OF BARRIERS, contains an example EAL for the potential loss of the i
containment barrier as indicated by, " Containment Pressure" '(Site-Specific) PSIG and increasing.'
The NUMARC/NESP-007 guidance states that the site-specific value used for this EAL should be the containment design pressure.
The licensee omitted this EAL but did include an EAL,
" Critical Safety function Status" ' Red Path Summary for Containment', as an equivalent EAL. The threshold for entering the Red Path Summary for i
Containment is the containment design pressure.
The licensee prefers to only include the ' Red Path Summary for Containment' EAL in the Callaway EAL scheme rather than including the ' Red Path Summary for Containment' EAL and a redundant containment pressure EAL because including both complicates the EAL scheme.
This deviation from the NUMARC/NESP-007 guidance is acceptable.
3.
Core Exit Thermocouple EAL for the Loss of Fuel Clad Barrier NUMARC/NESP-007, Table 4, PWR EMERGENCY ACTION LEVEL FISSION PRODUCT
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. l BARRIER REFERENCE TABLE THRESHOLDS FOR LOSS OR P0TENTIAL LOSS OF l
BARRIERS, contains an example EAL for the loss of the fuel clad barrier l
as indicated by ' Core Exit Thermocouple Readings Greater than (Site-specific) Degree F'.
The licensee did not include this EAL in the Callaway EAL scheme. The NUMARC/NESP-007 guidance states that the site-specific value used for this EAL should correspond to the core cooling -
Red Critical Safety Function status. The licensee included an EAL, l
" Critical Safety function Status" ' Red Path for Core Cooling' for the l
loss of the fuel clad barrier. The licensee prefers to only include the EAL, ' Red Path for Core Cooling' in the Callaway EAL scheme rather than l
including the core cooling red path EAL and a redundant core exit i
thermocouple reading EAL because including both complicates the EAL scheme.
This deviation from the NUMARC/NESP-007 guidance is acceptable.
4.
Unusual Event EAL for a Radiation Monitor Indication of Fuel Clad Damage The licensee's EAL scheme deviates from the NUMARC/NESP-007 guidance by not including an Unusual Event EAL for fuel clad degradation corresponding to the NUMARC/NESP-007 EAL, (SU4-1) "(Site-specific) radiation monitor readings indicating fuel clad degradation greater than Technical Specification allowable limits." The licensee states that failed fuel radiation monitor alarms are validated by chemistry sample to determine if Technical Specification limits are exceeded.
The licensee's EAL scheme contains an Unusual Event EAL for exceeding Technical Specification coolant activity limits based on chemistry sample results.
This deviation from the NUMARC/NESP-007 guidance is acceptable.
5.
Alert EAL for Turbine Failure Generated Missiles The licensee's EAL scheme deviates from the NUMARC/NESP-007 guidance by not including an Alert EAL for turbine missiles corresponding to the NUMARC/NESP-007 EAL, (HAl-6) " Turbine failure generated missiles result in any visible structural damage to or penetration of any of the following areas..." (all areas containing safety-related equipment).
The licensee states that turbine generated missiles can not affect safety systems due to their turbine configuration and that their Final Safety Analysis Report (FSAR) specifies that no specific protective measures are required for turbine missiles, which the licensee considers to indicate that no specific EAL is required. Although the condition of a turbine failure generated missile affecting on area containing safety related equipment is not specifically identified in an EAL, the Callaway EAL scheme does include ~an EAL, (Group 3, H.2.a.) ' Report of a tornado, high wind, vehicle crash, explosion, or other natural or destructive phenomena to any of the following Safe Shutdown areas:...,' which is applicable to an event of this nature.
This deviation from the NUMARC/NESP-007 guidance is acceptable.
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. 6.
Overly Conservative Radiation Monitor Setpoints The licensee's EAL scheme includes an Site Area Emergency EAL, (Group 1, C.1), 'A valid reading on the Unit Vent monitor, GT-RE-218... >8.1 E+5 pCi/s for 15 minutes' and a General Emergency EAL, (Group 1.D-1), ' A valid reading on the Unit Vent monitor, GT-RE-218... >8.1 E+6 pCi/s for 15 minutes.'
The setpoints for these EAls were calculated in accordance with the NUMARC/NESP-007 guidance, i.e., the setpoints were calculated to result in a given site boundary dose (whole body or thyroid, whatever is most limiting) considering a release from the plant corresponding to the FSAR source term and a radioactivity transport corresponding to annual average meteorology.
However, due to the assumed source term isotopic composition (i.e., the large fraction of Iodine assumed in the source term) the setpoint based upon the thyroid dose is about 1000 times lower than the setpoint based upon the whole body dose. The FSAR l
source terms are conservative estimates used in analysis for licensing the plant. However, the use of overly conservative assumptions to determine EAls which trigger protective actions is not appropriate.
Therefore, the licensee has committed to revise, by October 1,1994, the EAL setpoints to reflect a more accurate analysis of the potential dose consequence to the public.
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The proposed EAls, with the overly conservative setpoints, are acceptable in the interim until nec setpoints are calculated for the following reasons:
1.
The proposed EALs reduce the conservatism in the currently l
approved EALs.
2.
The proposed EAls are not used to classify events unless dose assessment (based upon actual source term and meteorology) can not be performed within 15 minutes of exceeding the setpoint.
3.0 CONCLUSION
Based on the review of the proposed EAL changes in EIP-ZZ-00101, Revision 15
" Classification of Emergencies," the staff concludes that the EAls are consistent with the guidance in NUMARC/NESP-007, with the identified variations.
Therefore, the changes are considered acceptable in accordance with Regulatory Guide 1.101, and meet the requirements of 10 CFR 50.47(b)(4) and Appendix E to 10 CFR Part 50.
Principal Contributor:
J. O'Brien, PEPB/NRR Date: May 4, 1994
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