ML20081J490
| ML20081J490 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 03/17/1995 |
| From: | Mccoy C GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20081J498 | List: |
| References | |
| LCV-0527, LCV-527, NUDOCS 9503270313 | |
| Download: ML20081J490 (11) | |
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. . Georg'a Pcmer Company 40 inverness Center Pwkway Pott 0",ce Box 1295 Gm+ognyn, A!abama 35201 Teiephone 205 877 7122
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- c. K. McCoy v.ce Pmea Nucies Georb>itt Potver Vt>ghe Proinct The southern electnc system March 17, 1995 LCV-0527 Docket Nos. 50-424 50-425 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:
VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS ALLOW CONTAINMENT AIRLOCK DOORS TO BE OPEN DURING FUEL MOVEMENT in accordance with the provisions of 10 CFR 50.90, Georgia Power Company (GPC) hereby proposes to amend the Vogtle Electric Generating Plant (VEGP) Unit I and Unit 2 Technical Speci6 cations, Appendix A to Operating Licenses NPF-68 and NPF-81. The revision to speci6 cation 3.9.4, Containment Building Penetrations, will allow the personnel airlock to be open during core alterations or movement ofirradiated fuel within the containment.
The current Technical Speci6 cations require that a minimum of one door in each airlock be closed during core alterations or movement ofirradiated fuel within the containment.
This requirement is to prevent the release of radioactive material in the event of a fuel handling accident. Since other work continues in the containment concurrently with fuel movement and core alterations, this speci6 cation results in excessively heavy use of the airlock during refueling outages which has led to failures of the airlock at VEGP as well as at other plants. The consequences of a fuel handling accident have been reanalyzed and it has been determined that projected doses remain within acceptable limits with the airlock doors open. The proposed change and bases for the change are similar to changes recently approved by the NRC for other plants.
Since the change is consistent with changes recently reviewed and approved by the NRC for plants similar to VEGP and the bases for the change does not involve any considerations that are different from those previously approved by the NRC, Georgia Power Company requests that this revision be approved by November 15,1995. This will allow the use of this improvement in the Technical Speci6 cation during 1.'ie 1996 refueling outages at VEGP.
9503270313 950317 DR ADOCK 0500 4
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1 GeorgiaPower d l U. S. Nuclear Regulatory Commission Page 2 The proposed change and the bases for the change are described in enclosure I to this .
letter. Enclosure 2 provides an evaluation pursuant to 10 CFR 50.92 showing that the l proposed change does not involve significant hazards considerations. Instructions for i incorporation of the proposed change into the Technical Specifications and a copy of the change are provided in enclosure 3. In accordance with 10 CFR 50.91, the designated .
state official will be sent a copy of this letter and all enclosures. l Enclosure 4 includes proposed changes to the index of the VEGP technical specifications. i The marked-up pages to the index revises page numbers, adds figures, and adds the main ,
feedwater isolation system. !
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 Company and that, to the best !
of his knowledge and belief, the facts set forth in this letter and enclosures are true.
l GEORGIA POWER COMPANY ,
By: .
C.K.Mc y 1 i
Sworn to and subscribed before me this y of Mds,1995.
'nfNotaryawl ublic i
v1. &J%
Enclosures:
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- 1. Basis for Proposed Change
- 2. 10 CFR 50.92 Evaluation l
- 3. Instructions for incorporation and Revised Pages i
- 4. Revision to Index l.
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I GeorgiaPbuier1 j U.S. Nuclear Regulatory Commission Page 3 l r
c(w): Georcia Power Comnany j Mr. J. B. Beasley, Jr. l Mr. M. Sheibani NORMS !
i U. S. Nuclear Reculatory Commission !
Mr. S. D. Ebneter, Regional Administrator !
Mr. D. S. Hood, Licensing Project Manager, NRR Mr. B. R. Bonser, Senior Resident Inspector, Vogtle :
State of Georgia !
Mr. J. D. Tanner, Commissioner, Department of Natural Resources j LCV-0527 t i
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ENCLOSURE 1 VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS ALLOW CONTAINMENT AIRLOCK DOORS TO BE OPEN DURING FUEL MOVEMENT BASIS FOR PROPOSED CHANGE Pronosed Chance i The proposed change to the Technical Specifications (TS) will change specification 3.9.4.b to the following: i l
"The emergency airlock is isolated by at least one airlock door, and the personnel airlock is isolable by at least one airlock door with a designated individual available to close the personnel airlock door; and,"
Basis Technical Specification 3.9.4, " Containment Building Penetrations," requires that a minimum of one personnel airlock (PAL) door, as well as other containment penetrations, be closed during core alterations or movement ofirradiated fuel within the containment.
This requirement is reflected in the Final Safety Analysis Report (FSAR), Section 15.7.4,
" Fuel llandling Accidents." The current accident analysis assumes that in the event of a fuel handling accident in the containment, a minimal radioactive release occurs because the containment is isolated within 10 seconds. The fuel handling accident analysis also assumes that the minimum water level above the top of the reactor vessel flange (23 ft) and the minimum decay time prior to fuel movement (100 hr.) are those required by Technical Specifications.
During a refueling outage, other work in the containment does not stop during fuel movement or core alterations. This requires that personnel operate the PAL doors to enter and exit the containment. It is estimated that there could be at least 250 airlock cycles per day during core altcrations. (At the most recent tefueling outage, there were 47,800 total containment entries of which 5,560 entries occurred during core alterations).
Such heavy use of the PAL was not anticipated during its design. The original purchase specification for the PAL states that its purpose is to allow entries during power operation or shutdown conditions and to withstand a pressure of 52 psig following an accident.
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ENCLOSURE 1 (CONTINUED)
VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS ALLOW CONTAINMENT AIRLOCK DOORS TO BE OPEN DURING FUEL MOVEMENT BASIS FOR PROPOSED CHANGE As a result of this unexpectedly heavy use, failures of the door seals, the handwheel shaft seals, the door closure mechanism position indicator, the latching device and other components have occurred. Our records indicate there have been approximately 35 maintenance work requests (MWR's) to repair the PAL doors at VEGP-Units 1 & 2. The excessive wear is occurring due to the excessive opening-closing of the doors during core alterations, which have resulted in the large number of work requests to repair the PAL's.
These failures of the PAL doors raise the concern that the PAL might not be able to be closed or scaled in the event of an accident.
From a practical standpoint, Specification 3.9.4 will not prevent all radioactive releases from the containment following a fuel handling accident. There are a large number of people in the containment during a refueling outage, even during fuel movement and core alterations. Should a fuel handling accident occur, it would take a number of cycles of the airlock to evacuate personnel from the containment. With each PAL cycle, more containment air would be released. While waiting for their turn to exit, the workers would be exposed to the released activity. If the containment airlock door remains open, plant personnel can quickly exit containment and the expected dose to persons in containment following a fuel handling accident would be reduced.
A new fuel handling accident analysis which assumes that the containment PAL door is open at the time of the accident has been performed. The details of this new analysis are described in Enclosure 2. The analysis shows that it is not necessary to have the PAL doors closed in order to show acceptable site boundary or control room doses following a '
fuel handling accident. A best estimate dose analysis was also performed to estimate the radiation dose to the individual designated to close the airlock door. The best estimate analysis is also discussed in Enclosure '
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S-ENCLOSURE 2 VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS ALLOW CONTAINMENT AIRLOCK DOORS TO BE OPEN DURING FUEL MOVEMENT 10 CFR 50.92 EVALUATION This proposed change revises Specification 3.9.4," Containment Building Penetrations,"
to allow the containment personnel airlock to be open during fuel movement and core alterations provided that one PAL door is operable, and a designated individual is I available to close the airlock door. Other technical specifications associated with refueling operations require the plant be in Mode 6 with 23 feet of water above the top of the reactor vessel flange (See Technical Specification 3/4.9.10 Water Level-Reactor Vessel).
Consistent with Standard Technical Specifications, features required for PAL operability will be added to the Bases. The Bases will state that in order for a PAL door to be operable, the door seal protectors are easily removed, that no cables or hoses are being run through the airlock, and that the airlock door is capable of being quickly closed.
Generic Anplicability The proposed change is generically applicable to those PWRs which are required to have the PAL closed during fuel movement and core alterations. Some PWRs are not required to close the PAL during fuel movement and core alterations. Justification for such specifications include a PAL which opens into a filtered area of the Auxiliary Building, such as the Spent Fuel Pool, or continuous use of a filtered containment exhaust.
110 wever, the majority of PWRs have specifications similar to VEGP and can make use of this change. This change is consistent with the technical specification revision that was granted to Calvert Cliffs on August 31,1994.
This proposed change was presented to the Technical Specification Improvement Program lead plants. All three PWR owners groups endorsed the proposed change.
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ENCLOSURE 2 (CONTINUED)
VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECIINICAL SPECIFICATIONS ALLOW CONTAINMENT AIRLOCK DOORS TO BE OPEN DURING FUEL MOVEMENT 10 CFR 50.92 EVALUATION Safety Analysis e
The purpose of the current requirement to have one containment PAL door closed during core alterations and fuel movement is to prevent the escape of radioactive material in the event of a fuel handling accident. This assumption is reflected in the analysis for this ,
accident as documented in the Vogtle FSAR, Section 15.7.4, " Fuel IIandling Accidents."
A new fuel handling accident analysis was performed which does not assume tha the containment PAL is closed at the time of the accident. The airlock doors in the new analysis were assumed to remain open for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The new analysis does assume that the fuel has decayed following shutdown for 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> prior to the accident and that there is at least 23 feet of water above the top of the reactor vessel flange, as required by Technical Specifications 3/4.9.3, Decay Time, and 3/4.9.10, Water Level-Reactor Vessel.
Experience has shown that the heavy use of the containment PAL during refueling has led to failures of the door, raising the concern that the door may be unavailable in the event of an accident. In addition, the current containment analysis assumes that there is no release after 10 seconds. Ilowever; a small release would occur as the personnel in ,
containment exit through the PAL door after a fuel handling accident. The personnel 1 would also be exposed to the radioactive material in containment while waiting to exit.
The Standard Review Plan guidelines for acceptable radiological consequences are 25%
or less of the 10 CFR Part 100 limits, e.g.,75 rem to the thyroid and 6 rem to the whole body. The current Fueling Ilandling Accident analysis for containment assumes almost l no offsite dose release (0.44 rem to the thyroid and 0.0017 rem whole body) because the j containment is isolated within 10 seconds. The current analysis for a fuel handling . .
accident in the Spent Fuel Pool (Fuel Handling Building) results in offsite doses of 73 l rem to the thyroid and 0.29 rem to the whole body, since no credit is taken for the fuel ;
handling building emergency filtration system charcoal filters. The results of these j analyses are presented in FSAR table 15.7.4-4," Radiological Consequences of a Fuel l llandling Accident." An analysis which assumes the PAL doors are open for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> I has similar radiological consequences as the case in the FSAR of a fuel handling l accident in the Spent Fuel Pool, which has already been reviewed and accepted by the )
NRC. This analysis projects a site boundary dose of 65.6 rem thyroid and 0.28 rem whole body. Another case was run where the PAL door was assumed to remain open for 15 minutes. This analysis results in an estimated site boundary dose of 8.2 rem to the thyroid and 0.025 rem to the whole body.
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j ENCLOSURE 2 (CONTINUED)
VOGTLE ELECTRIC GENERATING PLANT IEQUEST TO REVISE TECHNICAL SPECIFICATIONS ALLOW CONTAINMENT AIRLOCK DOORS TO BE OPEN DURING FUEL MOVEMENT 10 CFR 50.92 EVALUATION The projected dose to operators in the control room was also reviewed. This analysis assumed the airlock doors remained open for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, and projected that all doses to the plant operators would remain below 30 rem to the thyroid if only one of the four emergency control room filtration system was operating within 7 minutes. This system is initiated by either one of two control room air intake radiation monitors, RE-12116 or RE-12117. Establishment of emergency filtration in the control room ensures projected dose to control room operators will remain below Standard Review Plan limits of 30 rem thyroid and 6 rem whole body. (Note: There are 4 emergency filtration units for the combined Units 1&2 control room.)
A best estimate dose to the individual designated to close the airlock was estimated for a duration of 15 minutes. The estimated dose was 5.6 rem to the thyroid and 0.15 rem whole body without the use of a respirator. The best estimate dose is within SRP guidelines.
The proposed change contains restrictions on allowing both PAL doors to be open to ensure that at least one door will be available to perform its safety function. The restriction in Mode 6 with 23 feet of water above the top of the reactor vessel fiange as required by Technical Specification 3/4.9.10, Water Level - Reactor Vessel, provides suflicient time to respond to a loss of shutdown cooling. Requiring a door to be operable ensures that door seal protectors are easily removed and that the door is capable of being quickly closed. Prohibiting the blocking of the doorway by cables, hoses, etc.,
also ensures that the door can be closed. Requiring that a designated individual is available to close the door following evacuation of the containment will minimize the release of radioactive material.
This change does not represent a potential for an increased radiological dose at the site boundary due to a fuel handling accident. As shown in the FSAR, which has already been accepted by the NRC, the projected dose remains at or below the limits previously reviewed and accepted. Even though projected doses resulting from a fuel handling accident inside containment do increase, the doses remain below acceptance limits and the overall significance will be offset by the decreased potential radiation dose to workers and the increased availability of the PAL doors.
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ENCLOSURE 2 (CONTINUED)
VOGTLE ELECTRIC UENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS ALLOW CONTAINMENT AIRLOCK DOORS TO BE OPEN DURING FUEL MOVEMENT i 10 CFR 50.92 EVALUATION ,
This change results in an increase in the consequences of a previously analyzed accident, :
but the results of this change are clearly within all acceptance criteria. The criteria for fuel handling accident results are found in Standard Review Plan 15.7.4, Revision 1.
Section II.L, " Acceptance Criteria," provides exposure guidelines for offsite dose calculations. The guidelines given in the SRP are 75 rem to the thyroid and 6 rem to the 1 whole body. The results we have calculated, even assuming the airlock remains open for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, clearly fall within those acceptance criteria. A best estimate analysis for the designated individual remaining for 15 minutes at the airlock door is 5.6 rem to the thyroid and 0.15 rem whole body. Therefore, based on the information contained in this submittal, we believe that this change does not resuh in a significant hazard.
Pursuant to 10 CFR 50.92, Georgia Power Company (GPC) has evaluated the proposed revision to the Technical Specifications and has determined that operation of the facility in accordance with the proposed amendment would not involve any significant hazards considerations.
GPC has concluded the following: ,
- 1. The proposed change to the Technical Specifications does not involve a significant increase in the probability or consequences of an accident previously esaluated. The prcposed change to Specification 3.9.4 would allow the containment personnel j airlock (PAL) to be open during fuel nwement and core alterations. The PAL is ;
currently closed during fuel movement and core alterations to prevent the escape of i radioactive material in the event of a fuel handling accident. The PAL is not an )
initiator to any accident. Whether the PAL doors are opened or closed during fuel ,
movement or core alterations has no effect on the probability of any accident previously evaluated.
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ENCLOSURE 2 (CONTINUED)
VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS ALLOW CONTAINMENT AIRLOCK DOORS TO BE OPEN DURING FUEL MOVEMENT i
10 CFR 50.92 EVALUATION !
Allowing the PAL doors to be open during fuel movement and core alterations does increase the consequences of a fuel handling accident in the containment from essentially ,
no offsite dose release to an estimated release of 65.6 rem to the thyroid and 0.28 rem to the whole body. Ilowever, the calculated offsite dose release is lower than the case analyzed in the FSAR for an accident in the Spent Fuel Pool, with no filtration of the resulting release. In addition, the calculLJ doses are larger than the expected doses because the calculation does not incorporate the closing of the PAL door after the containment is evacuated. Closing the airlock door within 15 minutes results in a calculated offsite dose of 8.2 rem to the thyroid and 0.025 rem whole body. The projected dose to control room operators was reviewed and the projected dose remained below SRP acceptance limits as long as control room emergency ventilation was established within 7 minutes. It was assumed the individual assigned to close the airlock doors remained stationed at the airlock for 15 minutes. A best estimate dose analysis indicated this individual could be expected to receive 5.6 rem to the thyroid and 0.15 rem whole body. The proposed change will significantly reduce the dose to other workers in the containment in the event of a fuel handling accident by speeding the containment i evacuation pr + css. The proposed change will also significantly decrease the wear on the PAL doors a w ,3nsequently, increase the availability of the PAL doors in the event of an accident.
Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2. The proposed change to the Technical Specifications does not create the possibility of a new or different kind of accident from any accident previously evaluated because the proposed change afTects a previously evaluated accident, e.g., a fuel handling accident. It does not represent a significant change in the configuration or operation of the plant and, therefore, does not create the possibility of a new or different type of accident from any accident previously evaluated.
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VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECIINICAL SPECIFICATIONS ALLOW CONTAINMENT AIRLOCK DOORS TO BE OPEN DURING FUEL MOVEMENT 10 CFR 50.92 EVALUATION
- 3. The proposed change to the Technical Specifications does not involve a significant reduction in a margin of safety. The margin of safety as defined by 10 CFR Part 100 for a fission product release is 300 rem thyroid and 25 rem whole body for an individual exposed at the site boundary for two hours. The analysis shows values that are well below the acceptance limits. In fact, the margin remains essentially the same as previously evaluated by the NRC. There is no increase in calculated offsite dose resulting from n fuel handling accident. Therefore, the proposed change does not involve a significant reduction in a margin of safety. ,
i Based upon the preceding information, it has been determined that the proposed l Technical Specifications addition does not involve a significant hazards consideration as !
defined by 10 CFR 50.92. I l
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