ML20205F059
| ML20205F059 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 03/25/1987 |
| From: | Gallagher J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Butler W NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| CON-#287-2942, TASK-2.E.4.2, TASK-TM OL, NUDOCS 8703310077 | |
| Download: ML20205F059 (8) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 1215) 941 5001
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March 25, 1987 Docket No. 50-352 Mr. W. R.
Butler, Director Project Directorate No. 4 Division of Boiling Water Reactor Licensing U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555
Dear Mr. Butler:
The purpose of this letter is to provide additional information for Philadelphia Electric Company's January 13, 1987 Application for Amendment of Facility Operating License NPF-39 which requests changes to the Technical Specifications to reflect modifications to the Standby Gas Treatment System to connect it to the refueling floor volume as required by License Condition 2(c)(14).
The additional information was requested by Mr. Martin of the NRC staff in a March 3, 1987 letter to Mr. E. G. Bauer, Jr.
The questions are restated, followed by our responses, in the enclosure.
If you have any questions concerning our responses or require more additional information, please do not hesitate to contact us.
Very truly yours kOO 5
2 Enclosure cc:
Dr. T.
E. Murley, Administrator, Region I, USNRC Mr. Robert Martin, LGS Project Manager i
E. M.
Kelly, Senior Resident Site Inspector
{ g0\\
See Attached Service List
Docket No. 50-352 PHILADELPHIA ELECTP,IC COMPANY RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION DATED MARCH 3, 1987 STANDBY GAS TREATMENT SYSTEM MODIFICATIONS 1.
Question:
Pages 5 and 12 of the application refer to confusion which may exist if certain isolation signal surveillance requirements are included in both the primary and the secondary containment isolation section of T. S. Tables 3.3.2-1, 3.3.2-2, 3.3.2-3, and 4.3.2.1-1.
Please provide further basis for the proposal that it is adequate to include these requirements in only one section, the secondary contalrunent isolation section, of these T. S. Tables.
This should include clarification of whether any physical changes to the primary containment Isolation are involved with the proposed amencknent.
Response
There are no physical or hardware changes to the primary containment isolation system being implemented as a result of the requested deletion of signals R (Refueling Area high radiation) and T (Outside Atmosphere to Refueling Area Low Differential Pressure) fran Section 6 (The Primary Containment Isolation Section) of Technical Specification Tables 3.3.2-1, 3.3.2-2, 3.3.2-3, and 4.3.2.1-1.
The only change which results from this modification is the enabling of these instrument channels within the primary and refuelina area secondary containment isolation control systems.
Deletion of signals RST from Section 6 of T.S. Tables 3.3.2.1 Cet al.) is requested to correct an oversight which occurred during the development of the Limerick Technical Specifications. These signals have no relevance to primary contaloment isolation and should not have been included in the Primary Containment Isolation section of these tables. They should only have been included in the secondary containment isolation section since they perform only a secondary containment Isolation functlon.
Inclusion in both sections creates ccmplex cross-references in these Tables which could confuse the operators. Technical Specification 3.6.5.1.2 requires operab!Ilty of the refueling area secondary containment (and hence these isolation signal channels) only under Operational Condition b.
Technical Specification 3.6.3 requires operability of the affected primary containment isolation valves (and hence all supporting isolation signal channels) under Operational Conditions 1, 2, and 3.
Therefore, one or more of the following undesirable conditions may exist to cause needless confusion:
. 1.
A new operational condition would have to be defined in the Primary Containment Sections of Tables 3.3.2-1 Cet al.) to cover the case when Operational Condition 1, 2 or 3 occurs concurrently with Operational Condition". Otherwise, situations would arise whereby the "R" S "T" instrunent channels would be required to be operable at times when the refueling floor HVAC is not operable. The Instrunent sensors will not produce meaningful output signals under these conditions.
2.
An appropriately cross-referenced Action Statement in the Primary Containment Section of table 3.3.2-1 Cet al.) would be needed to prevent situations wherein the affected primary containment Isolation valves would have to be closed at times when primary containment integrity is not required. The use of such a cross-referenced Action Statement would be more compicx than the change proposed herein.
3.
In order to maintain operability of the 'T' instrunent channel (Outside Atmosphere to Refueling Floor Low P) while not causing isolation of the affected primary containment valves, the refueling floor HVAC would be required to be operable whenever primary containment integrity is required.
This would severely impact plant operations and create unnecessary delays in the construction of Unit 2.
Philadelphia Electric Company has evaluated the impact of the deletion of these isolation signals upon the primary containment isolation system, and has concluded that this change will not impact any primary containment isolation design requirements.
The affected containment isolation valves would continue to be closed by at Icast one of the following isolation signals which are required in Operational condition 1, 2, or 3:
1.
Reactor Vessel Low Water Level (Level 2) i 2.
High Drywell Pressure.
3.
High Radiation in the Reactor Enclosure.
In addition, the primary containment purge and vent valves would still be isolated upon a !cw differential pressure signal between the outside atmosphere and the reactor enclosure and the large diameter purge and vent valves would be Isolated by a high radiation signal in the North Stack. The design meets the redundancy and diversity requirements of SRP 6.2.4 as described in FSAR Section 6.2.4, Table 6.2-17, and the Limerick SER and also meets the requirements of NUREG-0737, Item II.E.4.2 as discussed in FSAR Section 1.13.2.
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2.
Question:
Page 7 of the appilcation notes the FSAR sections that are relevant to this issue. Please provide clarification regarding whether the FSAR isolation systen descriptions and SGTS design bases require revisions to reflect the proposed nodification.
Response
The appilcable sections of the LGS FSAR regarding the Isolation system and SGTS will be revised to reflect the proposed changes that result from this nodification. Since this nodification neets all the design requirements appilcable to the original design, none of the original design requiranents will be changed. A proposed mark-up of the FSAR changes has already been generated and is being presently reviewed per PECo procedures.
3.
Question:
Please provide further clarification of the vent discussed on page 9 of the appilcation with respect to whether any changes in the response nodes and design bases of the SGTS are introduced in this vent.
Response
The vent in the SGTS duct does not change any response modes or design bases of the SGTS. The vent is required to balance the SGTS air flow fnan the reactor enclosure and refueling area when i
both zones are connected to the common SGTS at the same time. One duct branch of the connon SGTS connects directly to the reactor enclosure recirculation system (RERS). Operation of the RERS fan generates a positive air pressure which can affect the control of air flow fran the refueling area. The vent will be balanced to I
provide filtered air from the RERS to the reactor enclosure SGTS l
duct by reducing the back-pressure fran the RERS fans. The vent i
is located inside the reactor enclosure secondary containnent.
Excess air which is not exhausted by the SGTS will be recirculated within the secondary containnent by the RERS.
The SGTS will continue to respond to reactor enclosure secondary containment Isolation signals as originally designed. The vent will not affect the drawdown time of 2 minutes 15 seconds required to restore the reactor enclosure pressure differential to a vacuum of - 0.25 In. Wg. and will have no effect on the offsite doses previously evaluated in Section 15.6 of the FSAR and in the SER i
Supplement 3 Section 15.6.
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Question:
Please provide a discussion of the effects of the relocation of the HPCI Barometric Condenser Vacuun Pmp Discharge on the conclusions reached in the application.
Response
The HPCI barometric condenser vacuun puTp (BCVP) discharge has been disconnected from the SGTS duct and reconnected to the reactor enclosure equipment compartment exhaust system.
If it were not relocated, the addition of the RERS vent would allow potential residual contamination to escape into the access area of the reactor enclosure when there is no SGTS flow. This modification also eliminates the need to place the RERS filters in the cooldown mode td establish SGTS air flow while performing routine surveillance tests on the HPCI system.
An evaluation of the offsite dose impact including a review of the effects on the charcoal filters, secondary containment doses, ALARA, and equipment qualification was performed. This evaluation, discussed below, verifled the acceptability of the relocation.
The offsite doses due to the discharge line relocation will not be increased. At its new location, the discharge will be filtered by the reactor enclosure equipment compartment exhaust system during nonnal operation and by the RERS filters if the reactor enclosure is isolated.
Post-LOCA when the reactor enclosure is isolated, the offsite dose contribution from the HPCI BCVP discharge will be reduced because of the filtering and diluting by both the RERS and SGTS prior to release. The filters in the reactor enclosure equipment compartment exhaust system, RERS, and SGTS will not be affected by the relocation because the HPCI BCVP has an internal moisture separator. This feature effectively removes any water droplets and limits the discharge to noncondensibles at approximately 100% relative humidity. The addition of the discharge effluents (15 cfm) to the reactor enclosure equipment compartment exhaust system (40,000 cfm) or the RERS (60,000 cfm) will have a negilgible effect on the relative hunidity and filter efficiency. The reactor enclosure doses are not increased beyond those previously evaluated in Section 15.6 of the FSAR and Equipment Qualification Report (EQR). The dilution of the discharge by the reactor enclosure equipment compartment system is ALARA by design. The doses which would be recirculated through i
the reactor enclosure by the RERS after a loss of offsite power event were determined to be within background levels for normal operation. The doses inside secondary containment following an i
event which required the continued operation of the HPCI (e.g.
ATWS event, or small break LOCA) would not exceed allowable equipment qualification levels. Conmitments made in the LGS EQR i
are still met.
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. Based on the above discussion, it can be concluded that the relocation of the HPCI BCVP discharge line did rot have any impact on the conclusions drawn in the application for amendment of the license.
5.
Question:
Page 14 refers to the addition of the increased SGTS fan capacity electrical loads on the diesel generators. Please provide a quantitative discussion of the effects of this increase on the conclusions reached in the application.
Response
The operating KW of the SGTS fan will increase from 4KW to 30KW and the loading on safeguard buses D11 and D12 will increase by 26KW each. The revised short time loading (10 min. - I hr.) of any diesel generator with either D11 or D12 diesel out of service, will increase to 2805KW and 2793KW respectively. The one hour and longer loading for any diesel generator with either 011 or D12 diesel out of service, will increase to 2798KW and 2786KW respectively. Since the short time rating Cup to 2 hrs.) and continuous rating of each diesel is 3135KW and 2850KW respectively, the increased loading has no effect on the neximun loading capacity of the diesel generators.
6.
Question:
Two accidents identified as relevant to SGTS operation and the proposed amendaents are the LOCA and the fuel handling accident.
Discuss those aspects of the proposed amendment which are significant with respect to whether the probability of an accident previously analyzed is significantly increased, e.g. whether changes to the reactor coolant systan, the reactor coolant pressure boundary or other factors which could influence the probability of a LOCA are involved. Similarly, with respect to the fuel handling accident, whether changes to fuel handling frequencies, equipnunt, procedures or other factors which could influence the probability of a fuel handling accident are involved. With respect to the consequences of these accidents please identify the current safety analysis of record and discuss any changes to it that would be required by the proposed amendment.
Response
The probability of an accident previously identified is not increased. The two accidents relevant to SGTS operation are the LOCA and the fuel handling accident (FHA).
No changes to the reactor coolant system, the reactor coolant pressure boundary, or other factors which could influence the probability of a LOCA are involved.
Likewise, no changes to fuel handling frequencies, equipnent, procedures or the other factors which could influence the probability of a FHA are involved.
. The current safety analysis of record with respect to the consequences of a LOCA is discussed in section 15.6 of the LGS FSAR.
The latest effective pages for this section are tabulated on the List of Effective Pages for Volune 14 of the FSAR with Revision 45, dated 12/85 being the nost recent. The current safety analysis of record with respect to the consequence of a FHA is discussed in section 15.7.4 of the LGS FSAR. The latest effective pages for this section are tabulated on the List of Effective Pages for Volume 15 of the FSAR with Revision 45, dated 12/85, being the nost recent. No changes to these sections are required by the proposed amendment.
7.
Question:
With respect to whether or not the proposed changes involve a significant reduction in a margin of safety, please discuss the existing margins reflected in the current safety analysis, including the radiological consequence norgins, and identify any significant changes attributable to the proposed anendnent.
Response
The changes resulting fran this nodification will have no effect on the design bases of the SGTS nor involve a significant reduction in the margin of safety. The design drawdown time and the reactor enclosure inleakage rate described in the Technical Specifications and the SER Supplement 3, Section 6.2.3 are not changed. The safety related node of the SGTS to reduce the halogen and particulate concentrations potentially present in the reactor enclosure secondary containnent atnosphere following a LOCA and in the refueling area secondary contalnnent atnosphere following a fuel handling accident prior to discharge to the environnent will not be affected.
No changes to the reactor coolant systens, reactor coolant pressure boundary, or other factors which could influence the probability of a LOCA are involved. Likewise, no changes to the fuel handling frequences, equipnent, procedures, or other factors which could influence the probabi'ity of a fuel handling accident are involved.
Reviews have been perforned regarding the effect of this nodification on the previously evaluated offstte doses, it has been concluded that there will be no effect on the post-LOCA offsite doses previously evaluated in Section 15.6.5 of the FSAR and in the SER Suppinnent 3, Section 15.6.
The najor changes associated with this nodification involve the installation of new equipannt and ductwork. This equipnent and ductwork will be fabricated and installed in accordance with an approved QA program which ncets as exceeds th9 original requirements. Additionally, extensive testing will be performed on new SGTS to assure proper operation prior to being placed in service.
_7-The proposed changes to the Technical Specifications which are requested as a result of this modification do not decrease the margin of safety because no requirements are deleted but rather requirements are added and values changed to represent the new design.
MJM/ Jet /03118701a
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