ELV-03182, Application for Amends to Licenses NPF-61 & NPF-81,revising TS 4.7.6,4.7.7 & 4.9.12 Re Min Heater Capacity,Charcoal Absorber Decontamination Efficiency & Relative Humidity Testing Requirements
| ML20086A587 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 11/11/1991 |
| From: | Mccoy C GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20086A591 | List: |
| References | |
| ELV-03182, ELV-3182, NUDOCS 9111190246 | |
| Download: ML20086A587 (9) | |
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,4 November 11, 1991 ELV-03182 1174 Docket Hos.
50-424 50-425 U. S. Nuclear Regulatory Commission ATIN: Docu:nent Control Desk Washington, D. C.
20555 Gentlemen:
V0GTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS 4.7.6. 4.7.7. AND 4.9.12 In accordance with the provisions of 10 CTR 50.90 and 10 CFR 50.59, Georgia Power Company (GPC) hereby proposes to amend the Vogtle Electric Generating Plant (VEGP) Unit 1 and Unit 2 Technical Specifications, Appendix A to Operating Licenscs NPF-61 and NPT-81.
This amendment modifies surveillance requirements 4.7.6, 4.7.7, and 4.9.12 by revising minimum heater capacity, charcoal adsorber decontamination efficiency, and relative humidity testing requirements. The Technical Specifications bases are also being revised to provide the design bases for these changes.
These modifications will result in increasing the margin between the actual heater power and the power required to fulfill the filtration units' design function.
Georgia Power Company letter ELV-02360, dated December 20, 1990, requested a temporary revision to Technical Specification 4.7.7.d.4 to remove a discrepancy between the surveillance requirement and the method of demonstrating the operability of the heaters.
The amended Technical Specification wording will be similar to the original Technical Specification.
Since the temporary Technical Specification expires upon restart following the second refueling outage for Unit 2 and the fourth refueling outage for Unit 1, GPC requests approval of this l
revision to the Technical Specifications by February 28, 1992, so it can be in l
place prior to the second refueling outage for Unit 2.
The proposed changes and their bases are described in Enclosure 1.
An l
evaluation pursuant to 10 CFR 50.92 showing that the proposed changes do not invr,1ve significant hazards considerations is provided as Enclosure 2.
Instructions for incorporation of the proposed changes into the Technical Specifications and a markup of the affected pages are provided in Enclosure 3.
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U. S. Nuclear Regulatory Commission ELV-03182 Page 2 in accordance with 10 CFR 50.91, the designated state official will be sent a copy of this letter and all enclosures.
Mr. C. K. McCoy states that he is a vice president of Georgia Power Company and is authorized to execute this oath on behalf of Georgia Power Com)any and that, to the best to his knowledge and belief, the facts set forth in t11s letter and enclosures are true.
GEORGIA POWER COMPANY
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By:
C. K. McCoy Sworntoandsubscribedbeforemethis/hayof LU4 A ht4 1991.
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Enclosures:
1.
Basis for Prcposed Change 2.
10 CFR 50.92 Evaluation 3.
Instruction for incorporation and Revised Pages I
c(w):
Georaia Power Company Mr. W. B. Shipman Mr. M. Sheibani NORMS U. S. Nuclear R nulatory Commission Mr, S. D. Ebneter, Regional Administrator Mr. D. S. Hood, Licensing Project Manager, NRR l
Mr. B. R. Bonser, Senior Resident Inspector, Vogtle 1'
State of Georaia Mr. J. D. Tanner, Commissioner, Department of Natural Resources
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f ENCLOSURE 1 V0GTLE ELECTRIC GENERATING PLANT TECHNICAL SPECIFICATIONS CHANGE ESF FILTER PERFORMANCE AND TESTING BASIS FOR PROPOSED CHANGE Proposed Chance The proposed changes to the Vogtle Electric Generating Plant (VEGP) Unit 1 and Unit 2 Technical Specifications will modify surveillances 4.7.6, 4.7.7, and 4.9.12 to revise minimum heater capacity, and additionally for the latter two, charcoal adsorber decontamination efficiency and relative humidity testing requirements. The Technical Specifications bases are also i
to be revised to provide the design bases for these changes.
A proposed markup of the affected pages is provided as Enclosure 3.
These proposed changes provide the corrective action discussed in our letter ELV-02360, dated December 20, 1990. The actual wording changes are contained in.
Basis Technical Specifications 4.7.6, 4.7.7, and 4.9.12 previously required that the heaters dissipate 118 1 6 kW, 80 1 4 kW, and 20 1 2 kW, respectively when tested in accordance with Section 14 of ANSI N510-1980.
Licensee Event Report (LER) 50-424/1990-023 described a voltage condition whereby heaters could be incapable of providing the heat dissipation required by the Technical Specifications, but would be capable of providing adequate heat dissipation to meet the heater design basis of maintaining relative humidity (RH) below 70 percent. A change to refer to the design basis 70 percent RH performance requirement in lieu of a specific heat dissipation value was approved in Amendments 37 and 17 to the Unit I and Unit 2 Technical Specifications, respectively in an NRC letter, dated January 15, 1991. The currently proposed changes will allow a return to wording similar to the original; i.e., reference to specific heat l
dissipation values will reduce the overly conservative heater performance requirements of the Technical Specifications and will revise the descriptions of the bases to reflect the safety analysis performance assumptions.
The revised Technical Specifications and analyses account for the minimum l
voltage expected at the heaters, based on the setpoint of the low voltage I
relays that are used to isolate the plant from the electrical grid in the I
event of a loss of offsite power.
They also consider conservative ventilation system air flow, initial room temperature and relative humidity, and ECCS leakage moisture input in determining filter performance requirements and capabilities to meet post accident dose limits of 10 CFR 100,11 and 10 CFR 50 Appendix A, General Design Criterion 19.
Technical Specifications surveillance requirements are being revised to be consistent with and support these design assumptions.
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ENCLOSURE 2 V0GTLE ELECTRIC GENERATING PLANT TECHNICAL SPECIFICATIONS CHANGE ESF FILTER PERFORMANCE AND TESTING 10 CFR 50.92 EVALUATION l
Pursuant to 10 CFR 50.92, Georgia Power Company (GPC) has evaluated the attached proposed amendment and has determined that operation of the facility in accordance with the proposed amendment would not involve a significant hazards consideration.
Backaround The present Technical Specifications (TS) surveillance for the control room emergency filtration system (CREFS), piping penetration area filtration and exhaust system (PPAFES), and fuel handling building post accident filter system (FHBPAFS) heater outputs was based on the purchase specification rated capacity for the heaters and not the minimum required value to support the HVAC system design basis function of maintaining offsite and control room doses within the limits of 10 CFR 100,11 and 10 CFR 50 Appendix A, General Design Criterion 19.
System confirmatory calculations prepared by the architect engineer did not address the effect of terminal voltage on the capacity of the heaters.
Licensee Event Report (LER) 50-424/1990-023 documented this problem for the PPAFES, and an interim revision to TS surveillance requirement 4.7.7.d.4 to allow continued operation was requested in our letter ELV-02360, dated December 20, 1990, and approved in a letter from the NRC, dated January 15, 1991.
In our letter, Georgia Power Company indicated that additional plant modifications or evaluations were being considered to increase the margin between the actual heater power and the power required to fulfill the design function, in anticipation that this would allow a return to wording similar to the original TS surveillance requirements.
This submittal provides the results of these PPAFES evaluations, and revises the CREFS and FHBPAFS TS surveillance requirements to be consistent with the design basis functional requirements in lieu of the overly restrictive procurement documents.
Analysis The purpose of the heaters in the ESF filtration systems is to help ensure that the offsite and control room doses meet the regulatory limitations cited above. The surveillance requirements are intended to verify that the heaters are operable and capable of reducing the relative humidity of the E2-1 r,
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l ENCLOSURE 2 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT TECHNICAL SPECIFICATIONS CHANGE ESF FILTER PERFORMANCE AND TESTING 10 CFR 50.92 EVALUATION incoming air to the level necessary to assure proper functioning of the
- filters.
Revised accident evaluations have been performed based on the following major assumptions:
1.
The.CREFS entering-airstream is maintained at less than or equal to 70 percent relative humidity based on conservative airflow (TS value plus tolerance) and relative humidity of 100 percent prior to entering the heater.
2.
No credit is taken for PPAFES or FHBPAFS heater function and humidity is not controlled; allowed filter decontamination efficiency is reduced consistent with Regulatory Guide 1.52.
- 3.
Post accident ECCS recirculation loop leakage into areas served by the PPAFES is reduced from the previously assumed 50 gpm to an assumed 2 gpm.-
4.
Charcoal adsorber relative humidity and methyl iodide penetration testing requirements are maintained consistent with the guidance of Regulatory Guide 1.52 and assumptions.1 and 2.
5.
The minimum voltage available at the heater terminals is that associated with degraded grid conditions-(approximately 414 V).
6.
No physical modifications will be made to.the plant or equipment.
The results of these analyses indicate that the as-built heater power exceeds the minimum requirements as shown in table 1.
Although no credit is taken for humidity control and heater' function for the PPAFES and FHBPAFS, the heaters will be maintained in.the design basis to provide for defense-in-depth.
The heater power dissipation requirements for these two systems are taken to be the as-installed capacity less a small margin. _ As a further result of these evaluations, the accident analysis indicates a reduction in offsite and control room doses compared to previous analyses as shown in table.2.
Reduced ECCS recirculation loop leakage will reduce-offsite.and control room doses..It does not impact any TS diractly, but could impact the bases and acceptability of the PPAFES TS.
In accordance with TS 6.7.4.a. this leakage value is kept as low as practical' and is currently less than 0.2 gpm. Thus, there is greater than a-factor of ten between the actual E2-2 1
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1 ENCLOSURE 2 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT TECHNICAL SPECIFICATIONS CHANGE ESF FILTER PERFORMANCE AND TESTING 10 CFR 50.92 EVALUA110N leakage and the value assumed in the revised accident analysis; therefore, the 2-gpm leakage assumption is considered to be conservative.
The charcoal adsorber testing requirements are unchanged for the CREFS.
For the PPAFES and FHBPAFS, the new relative humidity test requirement (95 percent RH) is made consistent with the requirements of ASTM D 3803 and the new allowable methyl iodide penetration acceptance criteria for tests is increased (to 10 percent) consistent with the guidance of Regulatory Guide 1.52 for uncontrolled humidity.
Previously the test requirement was for methyl iodide penetration of less than 0.2 percent when the accident analysis assumed 99 percent decontamination efficiency (1.0 percent penetration).
The revised test requirement is for penetration less than 10 percent when the accident analysis assumes a decontamination efficiency equivalent to methyl iodide removal of 30 percent (70 percent penetration).
As a result, the safety factor between the allowable methyl iodide penetration and the value which is assumed for the accident analysis is increased from five (1.0 percent /0.2 percent) to seven (70 percent /10 percent).
As the minimum available voltage at the heater terminals is that calculated for degraded grid conditions, and the expected voltage would be well above this, there is considerable conservatism in this assumption.
In addition, because no modifications are being made to the physical installation and the actual voltage during normal operations is expected to remain well above this level, the current requirement to operate with heater circuits energized for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per month remains sufficient to reduce potential moisture buildup on the charcoal adsorber.
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Conclusion Based on the above considerations, GPC has concluded the following concerning the requirements of 10 CFR 50.92:
1.
The revised surveillance requirements do not increase the probability or consequences of accidents previously evaluated in the Final Safety Analysis Report (FSAR). The filter systems do not function as initiators of any accidents evaluated in the FSAR.
The filter system l
will continue to perform its safety function as assumed in the revised L
dose analyses.
Because no modificaticos are being made to the filter systems and the surveillance requirements are consistent with the performance requirements of the filter system, it can be concluded that the filter systems will continue to function as designed.
Based on the results of the accident analysis, the changes will result in a reduction of the radiological consequences of a loss of coolant accident (LOCA) as previously evaluated in the FSAR.
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ENCLOSVRE 2 (CONTINVED)
V0GTLE ELECTRIC GENERATING PLANT TECHNICAL SPECIFICATIONS CHANGE ESF FILTER PERFORMANCE AND TESTING 19 CFR 50.92 EVALUATION 2.
The revisions to the surveillance requirements will not create the possibility of a new or different kind of accident other than those already evaluated in the FSAR.
No physical changes are being made to the filter systems, and the revised surveillance requirements demonstrate the continued operability of the filter systems; therefore, no new accident scenarios, failure mechanisms, or limiting single failures are introduced.
3.
The margin of safety provided by the Technical Specifications relative to the ability of the filter systems to perform their safety function is not significantly changed. The program to reduce leakage from those portions of systems outside containment that could contain highly radioactive fluids during a serious transient or accident to as low as practical levels is maintained, and the revised filtration system surveillance requirements continue to show that the filter systems will control radioactivity releases and resultant of fsite and control room doses to levels less than or equal to the acceptance values for previous accident analyses.
Based upon the preceding information, it has been determined that the
)roposed Technical Specifications change does not involve a significant lazards consideration as defined by 10 CFR 50.92 (c).
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ENCLOSURE 2 (CONTINVED)
V0GTLE ELECTRIC GENERATING PLANT TECHNICAL SPECIFICATIONS CHANGE ESF FILTER PERFORMANCE AND TESTING 10 CFR 50.92 EVALUATI0ff TABLE I REQUIRED kW REQUIRED kW REVISED TS INSTALLED kW PURCHASE FILTER UNIT BASED ON BASED ON kW VALUE BASED ON SPEC / PRIOR MIN. VOLT DESIGN VOLT BASED ON DESIGN VOLT FSAR & TS kW (414 VOLTS)
(460 VOLTS) 460 VOLTS (460 VOLTS)
(480 VOLTS)
CREFS 741 91 95 108 118 PPAFES 0
0.
652 73 80 FHBPAFS 0
0 162 18 20 1.
Power dissipation required to maintain 70 % relative humidity or less.
2.
No credit taken for hu.Idity control or heater function, however the heater is to be maintained for defense-in-depth.
TABLE 2 LOCA CONSEQUENCESI PREVIOUS ANALYSIS CURRENT ANALYSIS
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Site Boundary Dose Recirc Leakage 2.4 1.0 Total 53.3 51.9 Low Population Zone Recirc Leakage 2.9 1.5-Total 60.2 58.8 Control Room Recirc Leakage 0.6 0.3 Total-26.6 26.3 1.
No credit was or is taken for the FHBPAFS, and no changes are made to the function or operation of the CREFS; thus only LOCA consequences associated with PPAFES changes are affected.
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ENCLOSURE 3 V0GTLE ELECTRIC GENERATING PLANT REVISION TO TECHNICAL SPECIFICATIONS 4.7.6, 4.7.7, AND 4.9.12 INSTRUCTIONS FOR INCORPORATIQH The proposed changes to the VEGP Technical Specifications would be incorporated as follows:
Remove Pace Insert Paae 3/4 7-15* and 3/4 7-16 3/4 7-15* and 3/4 7-16 3/4 7-17* and 3/4 7-18 3/4 7-17* and 3/4 7-18 3/4 9-15 and 3/4 9-16 3/4 9-15 and 3/4 9-16 8 3/4 7-4 B 3/4 7-4 B 3/4 9-3 8 3/4 9-3 Overleaf page containing no change E3-1
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