ML20202H852
| ML20202H852 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 01/29/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20202H834 | List: |
| References | |
| NUDOCS 9902080256 | |
| Download: ML20202H852 (8) | |
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NUCLEAR REGULATORY COMMISSION 4
WASHINGTON, D.C. 2006H001
.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.105 ' TO FACILITY OPERATING LICENSE NPF-68 AND AMENDMENT NO. 83 TO FACILITY OPERATING LICENSE NPF-81 SOUTHERN NUCLEAR OPERATING COMPANY. INC.. ET AL.
VOGTLE ELECTRIC GENERATING PLANT. UNITS 1 AND 2 DOCKET NOS. 50-424 AND 50-425
1.0 INTRODUCTION
By application dated June 26,1998, as supplemented by letters dated September 18 and November 30,1998, Southern Nuclear Operating Company, Inc., et al. (the licensee) proposed license amendments to change the Technical Specifications (TS) for Vogtle Electric Generating Plant (VEGP), Units 1 and 2. The proposed changes would (1) revise the Applicability of Limiting Condition for Operation (LCO) 3.3.6, " Containment Ventilation Isolation Instrumentation," to refer to TS Table 3.3.6-1; the TS table would be revised to add a column entitled " Applicable Modes or Other Specified Conditions." Tnen, the applicable modes for Manual Initiation, Automatic Actuation Logic and Actuation Relays, and Safety injection would be revised to include only Modes 1,2,3, and 4. Consistent with this proposed change, LCO 3.3.6, Condition C and Required Action C.2 would be revised to reflect that system level manual initiation and automatic actuation would not be required during core alterations and/or during movement of irradiated fuel assemblies within the containment. Appropriate Bases changes would be included to reflect the proposed changes; (2) LCO 3;7.6 would be revised to delete the words " Redundant CSTs" from the title and LCO 3.7.6a would be deleted.
Appropriate Bases changes would be included to reflect the proposed changes; and
- (3) LCO 3.9.4 would be revised to allow the emerger:cy air lock and equipment hatch to be open during core alterations and/or during movement of irradiated fuel assemblies within the containment. In addition, the LCO statement would be revised to reflect that containment ventilation isolation (CVI) would be accomplished by manually closing the individual containment purge supply and exhaust isolation valves as opposed to a system level manual or automatic Initiation, consistent with the proposed change to LCO 3.3.6. Surveillance
' Requirement (SR) 3.9.4.2 would be revised to reflect the proposed change to CVI and a new SR would be applicable to an open equipment hatch. Appropriate Bases changes are included to reflect the proposed changes. The supplement dated November 30,1998, provided clarifying information that did not change the scope of the application and the initial proposed no significant hazards consideration determination. As will be discussed herein, those changes to the TS associated with the equipment hatch are not acceptable and are denied.
2.0 DISCUSSION AND EVALUATION The NRC staff has evaluated the licensee's proposed changes to the TS in the following areas:
(1) eliminate the requirement for operability of system level manual initiation, and automatic initiation, for closure of the containment purge supply and exhaust isolation valves during core
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. alteration and/or movement or irradiated fuel assemblies within containment; (2) allow the equipment hatch and emergency air lock to be open during core alterations, and/or movement of irradiated fuel assemblies inside containment; and (3) eliminate the requirements associated with nonredundant condensate storage tanks (CSTs). These evaluations are contained in the following sections.
2.1 Elimination of System Level Manual and Automatic Isolation of Containment Ventilation l
During Refueling and Movement of irradiated Fuel inside Containment l
The VEGP containments are equipped with containment purge supply and exhaust isolation valves to control normal pressure buildup during power ascension and eliminate airborne l
radiation prior to containment entry. The purge and mini-purge valves are automatically l
l Isolated by the containment ventilation isolation function (via the automatic actuation logic and j
actuation relays) upon high radiation in the containment or a safety injection signal. A manual system level actuation is available in the control room such that the all containment purge supply and exhaust isolation valves can be closed by using either of two switches. Alternately, each containment purge supply and exhaust isolation valve can be individually isolated by a hand switch inside the control room. The licensee described the purge and mini-purge valves in its November 30,1998, submittal, as follows:
'The containment ventilation isolation function isolates the containment purge supply and l
exhaust penetrations. These penetrations are equipped with four valves each (for a total of eight valves between the two penetrations). Each penetration is equipped with two valves in parallel inside containment and two valves in parallel outside containment.
The parallel flowpath arrangement provides each penetration with both a 24 inch flowpath that can be used in Modes 5 and 6 in parallel with a 14-inch flowpath that can be used for containment purge during Modes 1 through 4 as well as Modes 5 and 6.
The 24 inch purge supply valves are HV 2626A (inside containment) and HV 2627A (outside containment), and the 14 inch purge supply valves are HV-2626B (inside containment) and HV-2627B (outside containment). The 24-inch purge exhaust valves are HV-2628A (inside containment) and HV 2629A (outside containment), and the 14-inch purge exhaust valves are HV-2628B (inside containment) and HV-26298 (outside containment). Each valve is equipped with its own hand switch located in the control room on Section 2 of the OHVC (safety-related heating, ventilation and air conditioning) panels, and the hand switches are grouped together. FSAR Figure 18.1-1 shows the location of the OHVC panels in relation to the main control boards. The panels are easily accessible for an operator at the main control boards.
At the present time, TS 3.3.6, " Containment Ventilation Isolation Instrumentation," requires the l
following containment ventilation isolation instrumentation, specified in TS Table 3.3.6-1, to be operable in MODES 1,2,3, and 4, and during core alterations and/or movement of irradiated fuelinside the containment:
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- 1. Manual (sygtem level)intiation i
- 2. Automatic actuation logic and actuation relays
- 3. Containment radiation
- 4. Safetyinjection l
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i l The licensee is proposing that the above instrumentation, with the exception of containment radiation, be required to be operable only in Modes 1 through 4. The effect of the licensee's proposal would be to substitute manual, individual closure of the containment purge supply and exhaust isolation valves, for automatic closure, should a high radiation condition occur in the containment during core alteration and/or movement of irradiated fuelinside the containment.
On October 23,1997, the NRC issued Information Notice (IN) 97-78," Crediting of Operator Actions in Place of Automatic Actions and Modifications of Operator Actions, including Response Times? The purpose of IN 97-78 is to provide guidance for use by licensees in cases where an automatic safety function (e.g., automatic isolation of the containment purge supply and exhaust isolation valves) would be replaced with manual operator action (e.g.,
manual, individual, closure of the containment purge supply and exhaust isolation valves). The lN proposes that licensees who desire to substitute manual operator action for an automatic safety function address, but not necessarily be limited to, the following considerations: (1) the specific operator actions required; (2) the potentially harsh or inhospitable environmental conditions expected; (3) a general discussion of the ingress / egress paths taken by the operators to accomplish functions; (4) the procedural guidance for required actions; (5) the specific operator training necessary to carry out actions, including any operator qualifications required to carry out actions; (6) any additional support and/or equipment required by the operator to carry out actions; (7) a description of information required by the control room staff to determine whether such operator action is required, including qualified instrumentation used to diagnose the situation and to verify that the required actions have successfully been taken; (8) the ability to recover from credible errors in performance of manual actions; and (9) consideration of the risk significance of the proposed operator actions. In the licensee's November 30,1998, submittal, the licensee addressed the preceding factors as follows:
(1)
The specific operator actions required are to first recognize the need for containment ventilation isolation, and then to walk to the OHVC panels and manipulate the handswitches for the purge and exhaust isolation valves that may be open. As stated above, the control room personnel will be in direct communication with personnelinside containment at the refueling station. In addition, the containment radiation monitor alarms (gaseous, particulate, iodine, and area low range) will be available per TS 3.3.6 to alert the operators as well. In the event of a fuel handling accident, the control room will be immediately aware of the condition, and will be able to effect containment ventilation isolation within the time committed for closing the airlock doors, i.e.,15 minutes.
(2)
All of the required operator actions take place in the control room. There will be no harsh or inhospitable conditions encountered.
(3)
Referring to FSAR [ Final Safety Analysis Report] figure 18.1-1, it can be rman that the ingress / egress paths to accomplish the manual containment venWation isolation ate simple. Depending on where the operator is at the time that he is notified of the event, the operator simply has to walk a few feet to the OHVC panel to manipulate the hand switches.
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1 (4)
Procedural guidance for required actions is discussed above with respect to the i annunciator response procedures.
(5)
Operator training is discussed above. No special operator qualifications are i
L required to close the purge and exhaust isolation valves.
(6)
No additional support and/or equipment are required. lf there is only one operator "at the controls", then another operator will be dispatched to i
i manipulate the handswitches. However, this will not result in a delay beyond the 15 minutes allotted for closing the airlock (s).
(7)'
The information required by the control room staff is, (1) communication with personnel at the refueling station; (2) radiation alarms; and (3) the knowledge
' obtained from training that containment ventilation isolation may have to be accomplished by manually closing the open purge and exhaust isolation valves.
Position indication for each valve is displayed on the Main Control Board, hand switches, and plant computer.
(8)'
The only credible operator error to be considered would be the failure to close one or more of the open purge and exhaust isolation valves. It is expected that the operator will take action to recover from such an error, but such action would not be required because the dose analysis supporting the proposed change already assumes the release of all activity from a fuel handling accident (LCV-1149, June 26,1998).
(9)
Since the containment ventilation isolation can be accomplished within the same time allotted for closing the personnel airlock, there is no additional risk significance associated with the operator actions.
The NRC staff has reviewed the licensee's evaluation for the substitution of manual operator action for the automatic closure of the containment purge supply and exhaust isolation valves during core alteration and/or movement of irradiated fuelinside the containment. The NRC staff concludes that the substitution of manual operator action for the automatic closure of the containment purge supply and exhnst isolation valves during core alteration and/or movement of irradiated fuel inside the containment is acceptable in that it will not result in an increase in offsite dose as a result of a fuel handling accident. Moreover, as stated in the licensee's November 30,1998, submittal, the containment purge supply and exhaust isolation valves discharge locations are no closer to the control room ventilation intake than the personnel airlock (permitted to be open during core alterations and/or movement of irradiated fuel inside containment) and, thus, will not increase the dose to control room operators.
Consistent with crediting operator action for automatic or system level isolation of the containment purge supply and exhaust isolation valves, the licensee has proposed the following changes to the TS:
((1) in TS 3.3.6, the " Applicability" statement is currently Modes 1 through 4 and during coro
' alterations and movement of irradiated fuel inside containment. The applicability statement would be relocated to TS Table 3.3.6-1, and identified in a table column entitled, " Applicable Modes or Other Specified Conditions." in this regard, the licensee has proposed that the
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. " Applicable Modes or Other Specified Conditions" for the manual (system level) initiation, automatic actuation logic and actuation relays, and safety injection would be Modes 1 through 4 and for containment radiation, Modes 1 through 4 and Mode 6 (during core alterations and movement of irradiated fuel inside containment). This proposed change to the TS is acceptable in that only individual, manual, closure of the containment purge supply and exhaust isolation valves need be credited during core alteration and/or movement of irradiated fuelinside containment. A manual valve closure capability is demonstrated in Surveillance Requirement (SR) 3.9.4.2, which replaces the demonstration of automatic closure capability. The change to SR 3.9.4.2 is consistent with the change to TS 3.3.6 and is acceptable.
(2) In Condition "C" of TS 3.3.6, applicable only during core alterations and/or movement of -
irradiated fuelinside the containment, remedial action would be taken with "one or more Functions with one or more manual or automatic actuation channels inoperable;" this requirement is deleted since only individual, manual closure of the containment purge supply and exhaust isolation valves need be credited during core alteration and/or movement of irradiated fuelinside the containment. Required Action C.2, associated with i
" valves made inoperable by isolation instrumentation" is changed to " penetrations not in required status." Since the automatic isolation function of the containment purge suppiy and ' exhaust isolation valves may be inoperable during core alteration and/or movement of irradiated fuel inside the containment, the lack of at least one operable radiation monitoring channel might prevent timely closure of the containment purge supply and exhaust isolation valves in the event of a high radiation condition inside containment. For this reason, core
. alterations or movement of irradiated fuel inside containment must be immediately suspended according to TS 3.9.4, Required Actions A.1 and A.2. Altemately, the containment purge supply and exhaust isolation valves may be closed per TS 3.3.6, Required Action C.1. Accordingly, the proposed change to TS 3.3.6, Condition C and Required Action C.2 are acceptable.
(3) In TS 3.9.4, " Containment Penetrations," Item C.2 requires an operable containment ventilation isolation system, for each containment purge supply and exhaust isolation valve containment penetration, during core alterations or movement of irradiated fuel inside containment. The requirement for an operable " system"is replaced with the requirement for at least two operable valves in each containment purge supply and exhaust isolation valve i
containment penetration. This change to the TS is consistent with crediting individual valve closure in place of automatic isolation, and is acceptable.
2.2 Allowing the Equipment Hatch and Emergency Air Lock to be Open During Core Alterations, and/or Movement of Irradiated Fuel Assemblies inside Containment At the present time, TS 3.9.4a requires the equipment hatch to be closed and held in place by four bolts during core alterations or movement of irradiated fuel inside containment. The licensee has proposed to allow the equipment hatch to be open during core alterations or movement of irradiated fuelinside containment. In addition, at the present time, TS 3.9.4b allows the doors of the personnel air lock to be open during core alterations or movement of irradiated fuel inside containment provided that a " designated individual" is available to close i
the door in the event that a radiological emergency occurs. The licensee has proposed extending this requirement to include the emergency air lock.
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n 6-The proposed TS revision regarding containment boundary openings during core alterations and/or irradiated fuel movements is presented by the licensee from the perspective of incremental changes to the existing TS 3.9.4. Specifically, the licensee points out that the current TS 3.9.4 allows both personnel air lock doors to be open during core alterations or movement of irradiated fuel inside containment. Furthermore, it is indicated by the licensee that the basis for this is the acceptable fuel handling accident dose consequences (i.e., within 25 percent of the 10 CFR Part 100 limits and bounded by current fuel handling acchent analysis for the spent fuel poot).
The proposed change is the additional allowance for open emergency air lock doors and an open equipment hatch. The bases for the proposed open emergency airlock doors is stated to be the same as for the previously approved personnel air Icck doors. Considering the functional similarity of the two types of doors, and assuming the same TS conditions (a designated individual available to close the door in the event of a radiological emergency), the
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proposal to include open emergency airlock doors appears to be reasonab!e. It should be 1
noted that, as set forth in the licensee's November 30,1998, submittal, the " designated individual" to be available to close the emergency air lock doors is in addition to the " designated individual" to be available to close the personnel air lock doors. Accordingly, the proposed change to TS 3.9.4b is acceptable.
With respect to the equipment hatch, the bases described by the licensee include dependence on the availability and presence of trained hatch closure crews and necessary hardware, tools, and equipment for moving the hatch. With these provisions, the closure time is estimated to be 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The licensee indicates that the additional openings do not change the dose consequences of a fuel handling accident. A review of the proposed changes does not lead to a conclusion that the direct dose consequences are increased beyond the current acceptance criteria found in Standard Review Plan 15.7.4 and General Design Criterion 19.
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However, upon careful and conservative consideration of the role of the containment as one of the four principal fission product barriers, the inclusion of an open equipment hatch in the proposed revision runs contrary to the principle of defense in depth. In particular, the potential for relatively quick core uncovery (e.g., in 30 minutes) due to loss of decay heat removal (DHR) relating to cooling may make the timely closure of the equipment hatch unfeasible.
Concems of this type have been discussed in Generic Letter 88-17, " Loss of Decay Heat 1
Removal," dated October 17,1988. Specifically, the generic letter refers to concerns regarding fast acting accident sequences in Section 2.1, " Phenomena and impact," as well as in Section 2.2," Time Available for Mitigation." More detailed delineation of these concerns is presented in Enclosure 2 to Generic Letter 88-17 which reiterates the concerns involving fast acting accident sequences. The above considerations point to the need for quick and reliable containment isolation ( e.g., personnel and emergency air locks) to provide the assurance of a viable fission product barrier that can minimize the potential for exposing the public to any releases of radioactivity. The 1-hour closure time of the equipment hatch does not provide for adequate containment restoration time. Hence, the staff believes that an open equipment hatch is not acceptable as proposed. Accordingly, the proposed cnnge to TS 3.9.4a and the i
associated SR 3.9.4.2 are denied.
With regard to the equipment hatch, it should be noted that altemative approaches have been approved by the NRC staff. Specifically, there have been proposed changes by other licensees, that have been accepted by the NRC staff, involving equivalent closure devices that
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7 satisfied the closure requirements of the containment equipment hatch during core alterations or movement of irradiated fuel in containment. For example, the NRC staff has issued a safety evaluation and a license amendment for Indian Point Unit 3 (Safety Evaluation and License Amendment No. 69 to License No. DPR 64, as enclosures to a letter to the licensee, dated October 7,1986). The amendment permits a temporary closure plate in place of the equipment hatch during refueling operations. Similarly, the staff has approved the use of a retractable overhead door to satisfy closure requirements for the containment equipment hatch for Ginna (Safety Evaluation and License Amendment No. 62 to License No. DPR-18, as enclosures to a letter to the licensee, dated April 1,1996). The licensee may find it useful to consider such alternative approaches in lieu of the present proposed changes regarding the equipment hatch.
2.3 Elimination of the Requirements Associated with Nonredundant Condensate Storage Tanks The original design of the VEGP auxiliary feedwater (AFW) system contained an anomalous design feature in that the AFW pump recirculation lines for the motor driven pumps discharged to the 002 CST while the turbine driven AFW pump discharged to the 001 CST. This resulted in a situation where the flow from the recirculation line might be " lost" in that it might be returned to a CST other than the CST which was being used as the primary water source. The CSTs that do not have the recirculation flow returned to the CST being used as the AFW pump water source is referred in the TS as a "Non redundant CST." A modification was undertaken to the CSTs to allow the recirculation flow to be returned to the CST being used as the AFW pump water source; the CSTs that receive this modification are referred to in the TS as " Redundant CSTs." At the present time, TS 3.7.6 provides requirements for " Redundant CSTs" while TS 3.7.6a provides requirements for "Non-redundant CSTs." The following note appears in TS 3.7.6a,"This LCO shall be applicable to the Unit (s) which have not completed the design modifications required for redundant CSTs. This alternative Technical Specification is temporary and will no longer be required when both units have completed the modifications required to make the CSTs redundant."
The licensee's June 26,1998, application informed the NRC staff that all modifications to "Non-redundant CSTs" for VEGP Units 1 and 2 have been completed and that all CSTs are redundant. The application requests that TS 3.7.6a be deleted and the term " Redundant CSTs" be deleted from the title of TS 3.7.6. With completion of all modifications to the CSTs, the NRC staff agrees that TS 3.7.6a should be deleted. In addition, since all VEGP Unit 1 and 2 CSTs are redundant, the term " Redundant CSTs", in the title of TS 3.7.6 is no longer a necessary i
distinction and should be deleted. Therefore, this change is acceptable.
3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Georgia State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change requirements with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that
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- 6 i may be released offsite, and that there is no significant increase in Individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (63 FR 53955 dated October 7,1998). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CAR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
5.0 CONCLUSION
The Commission 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 ne conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: K.Campe D. Jaffe Date: January 29, 1999 i
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