RS-06-091, Response to NRC Response to Additional Information with Respect to Request for License Amendment Related to Application of Alternative Radiological Source Term
| ML061950332 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 07/14/2006 |
| From: | Bauer J Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RS-06-091 | |
| Download: ML061950332 (12) | |
Text
RS-06-091 July 14, 2006 U.S. Nuclear Regulatory Commission ATTN : Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. STN 50-456 and STN 50-457 Byron Station, Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455 10 CFR 50.90 Subject :
Response to NRC Request for Additional Information With Respect to Request for License Amendment Related to Application of Alternative Radiological Source Term
References:
- 1) Letter from K. R. Jury (Exelon Generation Company, LLC) to NRC, "Request for License Amendment Related to Application of Alternative Radiological Source Term," dated February 15, 2005
- 2) Letter from R. F. Kuntz (U. S. NRC) to C. M Crane (Exelon Generation Company, LLC), "Byron Station, Units 1 and 2, and Braidwood Station, Unit 1 and 2 - Request for Additional Information Related to Alternative Source Term Amendment Request," dated June 28, 2006 In the Reference 1 submittal, Exelon Generation Company, LLC (EGC) requested an amendment to Appendix A, Technical Specifications (TS), of Facility Operating License Nos. NPF-72, NPF-77, NPF-37, and NPF-66 for Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, respectively. The proposed amendment was requested to support application of an alternative source term methodology in accordance with 10 CFR 50.67, "Accident Source Term."
The Reference 2 letter identifies two issues related to the Reference 1 submittal that require additional information to be provided. The attachments to this letter provide the EGC response to the NRC request for information discussed during this conference call.
The information provided in this letter does not affect the supporting analysis for the original license amendment request as described in Reference 1 submittal. No other information contained in the referenced letter is affected by this additional information.
July 14, 2006 U.S. Nuclear Regulatory Commission Page 2 The No Significant Hazards Consideration and the Environmental Consideration provided in Attachment 1 of the Reference 1 letter are not affected by this additional information.
In accordance with 10 CFR 50.91(b) ; "State consultation," EGC is providing the State of Illinois with a copy of this letter and its attachments to the designated State Official.
H you have any questions about this letter, please contact David Chrzanowski at (630) 657-2816.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 14th day of July 2006.
Respectfully, IJ Joseph A. Bauer Manager - Licensing Attachments :
- 1) Response to NRC Request for Additional Information
- 2) Revised BraidwOod Station and Byron Station Technical Specification Pages BRAIDWOOD STATION UNITS 1 AND 2 Docket Nos. STN 50-456 and STN 50-457 License Nos. NPF-72 and NPF-77 and BYRON STATION UNITS 1 AND 2 Docket Nos. STN 50-454 and STN 50-455 License Nos. NPF-37 and NPF-66 Response to NRC Request for Additional Information
NRC Question 1 :
The note is being revised from :
Response to NRC Request for Additional Information Your submittal requested a change to the note on Technical Specification (TS) page 3.9.4-1 from LCD 3.713to TS3.7.13. Clarify how changing the wording from "LCO'to "TS" changes the applicability of the note, or alternatively, reword the note so that it explicitly defines when the note is applicable.
Exelon Generation Company, PLC (EGC) Response :
____________________________NOTE____________________________
Item a. only required when the Fuel Handling Building Exhaust Filter Plenum Ventilation System is not in compliance with TS 3.7.13, "Fuel Handling Building Exhaust Filter Plenum (FHB)
Ventilation System."
to :
____________________________NOTE-___________________________
LCO 3.9.4.a is not required to be met when in compliance with NCO 3.7.13, "Fuel Handling Building Exhaust Filter Plenum (FHB)
Ventilation System," or its associated Conditions and Required Actions. contains the revised Braidwood Station and Byron Station TS page 3.9.4-1 markups and typed pages.
NRC Question 2:
In the program manual section 5.5.11 the requested change is from 0.05% bypass to 1.0% bypass. The (105% bypass is a system integrity test specified in ANSI N510, "Testing of Nuclear Air Treatment Systems, "and stated in section C.5.d of Regulatory Guide (RG) 1.52, "Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Post-Accident Engineered-Safety-Feature Atmosphere Cleanup Systems in Light-Water-Cooled Nuclear Power Plants, " to insure leak tightness. Please explain how system integrity will be insured given this proposed deviation from the RG 1.52 guidance.
EGC Response:
The requirements of 10 CFR 50 Appendix A will be met as analyzed using an Alternative Source Term (AST). The AST analysis for the Control Room Ventilation System (VC) assumes a charcoal efficiency of 95%. The AST analysis does not distinguish whether the radioactive iodine leaks around (i.e., bypass) or penetrates through (i.e., efficiency) the filters. The bypass leakage and charcoal efficiency are accounted for as follows:
Page 1 of 4 Response to NRC Request for Additional Information The proposed change in percent bypass would not affect the integrity of VC system. The Braidwood Station and Byron Station Control Room Emergency Make Up Filter units are installed in a mild equipment qualification zone within the Control Room Envelope and are not subjected to outside weather conditions and fluctuations in temperature and humidity as would be expected with an exposed, roof-top unit.
The Control Room Emergency Make Up Filter units are tested in accordance with the Ventilation Filter Testing Program. The purpose of this surveillance is an in-place test to verify the integrity of the carbon adsorber filter assembly to assure that there are no gaps or pathways that allow the effluent to circumvent the charcoal beds. Tables 1 and 2 provide the results of the VC Emergency Make-Up System Bypass As-Left Leakage Test Results for Braidwood Station and Byron Station, respectively.
Table 1 Braidwood VC Emergency Make-Up System Bypass As-Left Leakage Results A Train Date Filter #
Results 03/1999 05/2000 07/2001 122002 12/2003 09/2005 OVC05FA % Bypass 1
0.010 0.022 0.011 0.008 0.010 0.020 OVC06FA % Bypass 0.008 0.014 0.013 0.007 0.015 0.010 B Train Date Filter #
Results 08/1999 01/2001 12/2001 05/2003 11/2004 05/2006 OVC05FB_ % Bypass 01014 0.006 0.011 0.008 0.007 0.013 OVC06FB % Bypass 0.010 0.006 0.033 0.007 0.009 0.0 AST Ideal Analyses Allowance (100%
95%)
5%
Bypass Allowance Value Allowed Inefficiency Safety Allowed Inefficiency Factor Penetration Value Response to NRC Request for Additional Information Table 2 Byron VC Emergency Make-Up System Bypass Leakage As-Left Test Results As demonstrated in Tables 1 and 2 above, the VC Emergency Make Up Filter bypass leakage test history for Braidwood and Byron Stations indicates a structurally sound enclosure with no adverse trends in system integrity over the course of an 18-month fuel cycle. Note that the measured Halide concentration values obtained during testing can be artificially elevated because of the breakthrough and/or desorption phenomena that occurs during the test sequence, which increases the system unavailability time. The purpose of increasing the allowed in-place leak test acceptance criteria (i.e., the bypass value) is to reduce VC system unavailability during testing.
Breakthrough occurs when the tracer gas saturates the adsorbent bed. Much like a sponge, the adsorbent bed can only retain a glen volume of a particular substance. As more tracer gas is introduced into the adsorbent bed, it begins to "breakthrough" on the downstream side ; thus artificially elevating the test results. Desorption occurs when the adsorbed tracer has migrated through the adsorbent bed. As a tracer gas is injected upstream of the adsorbent bed, tracer gas may become clesorbed/re leased resulting in a rise in the downstream concentration, similarly artificially increasing the test results.
Even though the amount of breakthrough and desorption is small, the 0.05% acceptance criteria is challenged and contributes to VC system unplanned unavailability because to eliminate these effects and achieve acceptable test results, the system must be purged, troubleshooting performed, and testing repeated. Increasing the allowed bypass leakage to 1 %
will continue to adequately verify system integrity testing without unnecessarily increasing VC availability.
The charcoal penetration test is performed to determine the efficiency of the charcoal bed.
The charcoal is removed and sent to a vendor for laboratory testing. Tables 3 and 4 provide the results of the VC Emergency Make-Up System Charcoal Penetration Test Results for Braidwood Station and Byron Station, respectively.
A Train Date Filter #
Results 03/1999 122000 081002 02/2004 08/2005 OVC05FA % Bypass 0.000 0.015 0.000 0.000
- 0. 000 OVC06FA % Bypass 0.000 0.019 0.000 0.000 0.000 B Train Date Filter #
Results 03/1999 11/2000 071002 124003 02/2005 OVC05FB % Byltass 0.000 0.032 0.048 0.012 0.000 OVC06FB % Bypass 0.000 0.010 0.031 0.042 0.014 Response to NRC Request for Additional Information Table 3 Braidwood VC Emergency Make-Up System Charcoal Penetration Test Results Table 4 Byron VC Emergency Make-Up System Charcoal Penetration Test Results Tables 3 and 4 demonstrate excellent performance of the charcoal filters when compared to the 2% penetration value supported by the AST analyses.
As provided in the submittal from K. R. Jury (Exelon Generation Company, LLC) to NRC, "Request for License Amendment Related to Application of Alternative Radiological Source Term," dated February 15, 2005, the Fuel Handling Accident (FHA), the most limiting design bast accident from a Control Room (CR) dose perspective, results in a calculated CR dose of 4.55 rem TEDE assuming a 95% filter efficiency as previously discussed. This represents a margin of 0.45 to the 5.00 rem TEDE limit. Considering the conservative inputs and assumptions in the AST analysis of Braidwood Station and Byron Station FHA, the contribution to CR dose from 1% bypass is insignificant.
Given the structural reliability of VC Emergency Make Up Filter units and their consistent low levels of bypass leakage, the excellent performance of the charcoal filters in their laboratory penetration tests, the margin to dose limits for CR personnel, and the inherent conservatism of the AST analyses, the proposed change in allowable bypass leakage is an acceptable alternative which will enhance the availability of the VC system.
A similar proposed change in allowable bypass leakage (i.e., from 0.05% to 1%) was previously approved for Catawba Station in a submittal from S. E. Peters (U. S. NRC) to D. M. Jamil (Duke Energy Corporation), "Catawba Station, Units 1 and 2 RE: Issuance of Amendments," dated September 30, 2005 (ADAMS Accession Number ML0527303120).
Date A Train 05/1998 12!1999 07/2001 12/2002 01/2005 020006
% Penetration 0.015 0.113 0.049 0.066 0.010 0.023 Date B Train 06/1996 1111_997 06_/1999 122002 072002 020005
% Penetration 0.009 0152 0.029 0.043 0.015 0.011 Train A
Date 02/1999 012000 06/2001 11/2002 05/2004 080005
% Penetration 0.009 0.067 0.042 0.248 0.024 0.001 Date B Train 07/1 999 121000 11/2001 05/2003 10/2004 012006
% Penetration 0.002 0.048 0.002 0.030 0.037 0.001 BRAIDWOOD STATION UNITS 1 AND 2 Docket Nos. STN 50-456 and STN 50-457 License Nos. NPF-72 and NPF-77 and BYRON STATION UNITS 1 AND 2 Docket Nos. STN 50-454 and STN 50-455 License Nos. NPF-37 and NPF-66 License Amendment Request "Alternative Source Term Implementation" Revised Braidwood Station and Byron Station Technical Specification Pages Markup of Braidwood and Byron Stations Technical Specification Pages 3.9.4-1 and Typed Braidwood and Byron Stations Technical Specification Pages 3.9.4-1
3.9 REFUELING OPERATIONS 3.9.4 Containment Penetrations LCO 3.9.4 P.
The containment penetrations shall be in the following status :
a.
b.
C.
PLICABILITY :
LQujr-j ng-CQTZr Dwring movemen containment.
LCO 3.9.4.a is riot req LCO 3.7.13, "Fuel Ventilation System, Required Act',ons.
BRAIDWOOD - UNITS 1 & 2 Containment Penetrations 3.9.4 One door in the personnel air lock closed and the equipment hatch held in place by ? 4 bolts ;
One door in the emergency air lock closed ;
and Each penetration providing direct access from the containment atmosphere to the outside atmosphere either :
1.
Closed by a manual or automatic isolation valve, blind flange, or equivalent, or 2.
Capable of being closed by an OPERABLE Containment Ventilation Isolation System.
Item a. only Exhaust Filt compliance Filter Ple
_____________NOT equired when the Plenum Ventila LCO 3.7.13, "
FHB) Ventilat uel Handling B ilAing on System is not Handling Bui ng Exhaust System."
REPLACE WITH
____________________________MOTE____________________________
o be met when in compliance with Exhaust Filter Plent,,m (FHB) oeiated the Conditions and 3.9.4 - 1 assemblies within
---fMCENTLY IRRADIATED FUEL Amendment XXX
3.9 REFUELING OPERATIONS 3.9.4 Containment Penetrations Containment Penetrations 3.9.4 LCO 3.9.4 The containment penetrations shall be in the following status :
a.
One door in the personnel air lock closed and the equipment hatch held in place by n 4 bolts ;
b.
One door in the emergency air lock closed ; and c.
Each penetration providing direct access from the containment atmosphere to the outside atmosphere either :
1.
Closed by a manual or automatic isolation valve, blind flange, or equivalent, or 2.
Capable of being closed by an OPERABLE Containment Ventilation Isolation System.
____________________________NOTE_________________________
LCO 3.9.4.a is not required to be met when in compliance with LCO 3.7.13, "Fuel Handling Building Exhaust Filter Plenum (FHB) Ventilation System,"' or its associated the Conditions and Required Actions.
APPLICABILITY :
During movement of RECENTLY IRRADIATED FUEL assemblies within containment.
BRAIDWOOD - UNITS 1 & 2 3.9.4 - 1 Amendment xxx
3.9 REFUELING OPERATIONS 3.9.4 Containment Penetrations LCO 3.9.4 The containment penetrations shall be in the following status :
b.
C.
One door in the personnel air lock closed and the equipment hatch held in place by ~! 4 bolts ;
One door in the emergency air lock closed ; and Each penetration providing direct access from the containment atmosphere to the outside atmosphere either :
1.
Closed by a manual or automatic isolation valve, blind flange, or equivalent, or 2.
Capable of being closed by an OPERABLE Containment Ventilation Isolation System.
Item a. only Exhaust Filt compliance Filter Plen
____________NOT ----------------- ---------
equired when the uel Handling Buil ing
/
- n Plenum Ventilat'on System is not *n th LCO 3.7.13, "
el Handling Buil ing Exhaust (FHB) Ventilati n System."
_________________ -________________f_____________
APPLICABILITY :
Wurin~~
-ALT During movement o containment.
,EPLACE WITH
____________________________MOTE____________________________
LCO 3.9.4.a is not required to be met when in compliance with NCO 3.7.13, "Fuel Handling Building Exhaust Filter Plenum (FHB Ventilation System," or its associated the Conditions and aired Actions.
BYRON - UNITS 1 & 2 3.9.4 - I Containment Penetrations 3.9.4 Amendment XXX
3.9 REFUELING OPERATIONS 3.9.4 Containment Penetrations Containment Penetrations 3.9.4 LCO 3.9.4 The containment penetrations shall be in the following status :
One door in the personnel air lock closed and the equipment hatch held in place by ~! 4 bolts ;
b.
One door in the emergency air lock closed ; and C.
Each penetration providing direct access from the containment atmosphere to the outside atmosphere either :
1.
Closed by a manual or automatic isolation valve, blind flange, or equivalent, or 2.
Capable of being closed by an OPERABLE Containment Ventilation Isolation System.
____________________________NOTE____________________________
LCO 3.9.4.a is not required to be met when in compliance with NCO 3.7.13, "Fuel Handling Building Exhaust Filter Plenum (FHB) Ventilation System," or its associated the Conditions and Required Actions.
APPLICABILITY :
During movement of RECENTLY IRRADIATED FUEL assemblies within containment.
BYRON - UNITS 1 & 2 3.9.4 - 1 Amendment xxx