ML18039A608
| ML18039A608 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/17/1998 |
| From: | De Agazio A NRC (Affiliation Not Assigned) |
| To: | Scalice J TENNESSEE VALLEY AUTHORITY |
| References | |
| TAC-M98205, TAC-M98206, NUDOCS 9811200178 | |
| Download: ML18039A608 (12) | |
Text
Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority
~ 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801 Woverber 17, 1998
SUBJECT:
BROWNS FERRY NUCLEAR PLANT, UNITS 2 AND 3 - REQUEST FOR ADDITIONALINFORMATIONREGARDING TECHNICALSPECIFICATION CHANGE NO. 376 - EXTENDED EMERGENCY DIESEL GENERATOR ALLOWEDOUTAGE TIME (TAC NOS. M98205 AND M98206)
Dear Mr. Scalice:
By letter dated March 12, 1997, the Tennessee Valley Authority (TVA)submitted a request for amendment of Operating Licenses DPR-52 and DPR-68 for the Browns Ferry Nuclear Plant, Units 2 and 3 respectively.
The proposed amendment would change the technical specifications for the units to permit an increase in the allowed outage time to 14 days from the current 7 days for each emergency diesel generator (EDG). TVAasserted that the purpose of the change is to provide additional flexibilityto perform repair or preventive maintenance on the EDGs. The proposed change is being reviewed and evaluated by the U. S. Nuclear Regulatory Commission staff, however, for the staff to complete its evaluation, the information described in the enclosure is required.
This request was discussed with Mr. David Matherly of the Browns Ferry licensing staff on October 7 and November 6, 1998. A target response date of March 30, 1999, was agreed to.
Sincerely, Original signed by:
Albert W. De Agazio, Sr. Project Manager Project Directorate II-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-260, 50-296 Serial No. BFN-98-027
Enclosure:
Request for Additional
'nformation IIII' C~'Ital CEPV ccw/encl: See next page tl.'Docket.p~ite F. Hebdoo
- PUBLIC, B. Clayton BFN-3 R/F A. De Agazio J. 'Zwolinski (A)
'ee previous concurrence ACRS L. Plisco, Region II J. Calvo A. Pal
~l O. Chopre R. Barrett A. El-Bassioni S. Lee.
DOCUMENT NAME: G:iBFNi98205RAI.WPD To receive a copy of this document, indicate in the box: "C" = Copy without attachment/enclosure "E" = Copy with attachment/enclosure "N" = No co
- See revious concurrence NAME ADeAgazi OFFICE PM:PDII-3 LA:PDII-3 BClayton D:PDZI-3 FHebdon BC:EELB JCalvo BC:SPSB RBarrett DATE 11/
/98 11/
/98 11/ I
/98 Official Record Copy 11//7 /98 11/
/98 98ii200i78 98iii7 PDR ADOCK 050002M P
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Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority
'A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801 Rveiber 17, 1998
SUBJECT:
BROWNS FERRY NUCLEAR PLANT, UNITS 2 AND 3 - REQUEST FOR ADDITIONALINFORMATIONREGARDING TECHNICALSPECIFICATION CHANGE NO. 376 - EXTENDED EMERGENCY DIESEL GENERATOR ALLOWEDOUTAGE TIME (TAC NOS. M98205 AND M98206)
Dear Mr. Scalice:
By letter dated March 12, 1997, the Tennessee Valley Authority (TVA)submitted a request for amendment of Operating Licenses DPR-52 and DPR-68 for the Browns Ferry Nuclear Plant, Units 2 and 3 respectively.
The proposed amendment would change the technical specifications for the units to permit an increase in the allowed outage time to 14 days from the current 7 days for each emergency diesel generator (EDG). TVAasserted that the purpose of the change is to provide additional flexibilityto perform repair or preventive maintenance on the EDGs. The proposed change is being reviewed and evaluated by the U. S. Nuclear Regulatory Commission staff, however, for the staff to complete its evaluation, the information described in the enclosure is required.
This request was discussed with Mr. David Matherly of the Browns Ferry licerising staff on October 7 and November 6, 1998. A target response date of March 30, 1999, was agreed to.
Sincerely, Original signed by:
Albert W. De Agazio, Sr. Project Manager Project Directorate II-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-260, 50-296 Serial No. BFN-98-027
Enclosure:
Request for Additional Information ccw/encl: See next page DISTRIBUTION:
Docket File F. Hebdon PUBLIC B. Clayton BFN-3 R/F A. De Agazio J. Zwolinski (A)
'ee previous concurrence ACRS L. Plisco, Region II J. Calvo A. Pal O. Chopra R. Barrett A. El-Bassioni S. Lee DOCUMENT NAME: G:)BFN(98205RAI.WPD To receive a copy of this document, indicate in the box: "C" = Copy without attachment/enclosure "E" = Copy with attachment/enclosure "N" = No co
- See revious concurrence NAME ADeAgazi OFFICE PM: PDII-3 LA:PDII-3 BClayton D:PDII-3 FHebdon BC:EELB JCalvo BC:SPSB RBarrett DATE 11/
/98 11/
/98 11/ i
/98 Official Record Copy 11//7 /98 11/
/98
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++*++'NITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Noverber 17, 1998 Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801
SUBJECT:
BROWNS FERRY NUCLEAR PLANT, UNITS 2 AND3-REQUEST FOR ADDITIONALINFORMATIONREGARDING TECHNICALSPECIFICATION CHANGE NO. 376-EXTENDED EMERGENCY DIESEL GENERATOR ALLOWEDOUTAGE TIME (TAC NOS. M98205 AND M98206)
Dear Mr. Scalice:
.I By letter dated March 12, 1997, the Tennessee Valley Authority (TVA)submitted a request for amendment of Operating Licenses DPR-52 and DPR-68 for the Browns Ferry Nuclear Plant, Units 2 and 3 respectively.
The proposed amendment would change the technical specifications for the units to permit an increase in the allowed outage time to 14 days from (he current 7 days for each emergency'diesel generator (EDG). TVAasserted that the purpose of the change is to provide additional flexibilityto perform repair or preventive maintenance on the EDGs. The proposed change is being reviewed and evaluated by the U. S. Nuclear Regulatory Commission staff, however, for the staff to complete its evaluation, the information described in the enclosure is required.
This request was discussed with Mr. David Matherly of the Browns Ferry licensing staff on October 7 and November 6, 1998. A target response date of March 30, 1999, was agreed to.
Sincerely, Docket Nos. 50-260, 50-296 Serial No. BFN-98-027
Enclosure:
Request for Additional Information Albert W. De Agazio, Sr.
roject Manager Project Directorate II-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation ccw/encl: See next page
'r. J. A. Scalice Tennessee Valley Authority BROWNS FERRY NUCLEAR PLANT CC:
Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Jack A. Bailey, Vice President Engineering 8 Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Karl W. Singer, Site Vice President Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 General Counsel Tennessee Valley Authority ET 10H 400 West Summit Hill Drive Knoxville, TN 37902 Mr. Raul R. Baron, General Manager Nuclear Assurance Tennessee Valley Authority 5M Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Robert G. Jones, Plant Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Mr. Mark J. Burzynski, Managar Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Timothy E. Abney, Manager Licensing and Industry Affairs Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL35609 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 61 Forsyth Street, SW., Suite 23T85 Atlanta, GA 30303-341,5 Senior Resident Inspector U.S. Nuclear Regulatory Commission Browns Ferry Nuclear Plant I0833 Shaw Road Athens, AL35611 State Health Officer Alabama Dept. of Public Health 434 Monroe Street Montgomery,'AL 36130-1 70I Chairman Limestone County Commission 310 West Washington Street Athens, AL 35611
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E ERGENCY D SEL GENERAT LLOWEDOUTA E
I E
B OWN F
Y NUCLEA PLAN N T 8
N 3
N MBE S M9820 D
2 1.
As stated in the Tennessee Valley Authority's (TVA's) March 12, 1997, letter, the purpose of the proposed amendment is to allow an increased outage time during plant power operation for performing emergency diesel-generator (EDG) preventive mintenance (PM), which would include disassembly of the EDG. The staff is concerned that disassembly of an EDG would subsequently require pre-operational testing of that EDG (such as full load rejection tests) following this maintenance while the plant is operating instead of during shutdown, which,has been the past practice.
To resolve this concern, the following should be addressed:
a.
What would be the typical and worse-case voltage transients on the 4160-V safety buses as a result of a full-load rejection?
b.
Ifa full-load rejection test is used to test the EDG governor after maintenance, what assurance would there be that an unsafe transient condition would not occur on the safety bus (i.e., load swing or voltage transient) due to improperly performed maintenance or repair of a governor?
-7 c.
Using maintenance and testing experience on the EDG, identify possible transient conditions caused by improperly performed maintenance on the EDG governor and voltage regulator.
Predict the electrical system response to these transients.
Also, TVAshould provide information on the tests to be performed after PM to declare the EDG operable and provide justification for performing such tests at power.
'2.
TVAhas stated that during Browns Ferry Nuclear Plant's 23 years of operation, there has never been a complete loss of offsite power event.
However, Licensee Event Report 97-001-00 indicated that on March 5, 1997, Unit 3 lost offsite power and EDGs started and tied to their respective buses.
It appears that at least once BFN experienced a
loss of offsite power event.
Please comment.
3.
The Bases Section for TS 3.9.B.3 for Unit 2 and TS 3.9.B.2 for Unit 3 should be modified providing the basis for this change.
4.
The PSA Analysis section of your application includes information that is relevant to assessing the risk associated with the proposed change (e.g., baseline core damage frequency (CDF) and new CDF). However, the subject section lacks other pertinent information (e.g., probability risk assessment (PRA) quality and three-tiered approach'or licensees to evaluate the risk associated with proposed TS allowed outage time changes).
'ier 1 is an evaluation of the impact on plant risk of the proposed technical specification (TS) change as expressed by the change in core damage frequency, the incremental conditional core damage probability, the change in large early release frequency, and the incremental conditional large early release probability. Tier 2 is an identification of potentially high-risk configurations that could exist ifequipment in addition to that associated with the change were to be taken out of service simultaneously, or other risk significant operational factors such as concurrent system or equipment testing were also involved. Tier 3 is the establishment of an overall configuration risk management program to ensure that other potentially lower probability, but nonetheless risk-significant, configurations resulting from maintenance and other operational activities are identified and compensated for. A detailed discussion of the three-tiered approach is provided in Regulatory Guide (RG) 1.177.
Enc1osure
0 I~
The staff has recently published several RGs which discuss approaches for risk-informed decision-making and staffs expectations for using PRA in licensing actions.
For the proposed change, TVAshould provide the staff with information that is consistent with the guideline provided in RG 1.177, An Approach forPlant-Specific, Risk-Informed Decision making: Technical Specif cations, and RG 1.174, An Approach for Using Probabilistic Risk Assessmentin Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis.
TVAshould refer to RG 1.177 for a comprehensive and detailed guideline to provide sufficient information required for a staff review. As described in RG 1.177, TVAshould address the questions posed for the three tiers as well as questions addressing the quality of PRA. In adhering to RG 1.177, TVAshould develop a configuration risk management program and incorporate it in the proposed risk-informed TSs.
In addressing Tier 2 and Tier 3 requirements, also include discussions on the following specific issues:
a.
Because of the potential safety impact of the extended EDG allowed out-of-service time (AOT) for PM, the staff believes that certain compensatory measures are needed during the extended EDG AOT to assure safe operation of the plant. Provide a discussion of how each condition listed below would be addressed:
1.
The TSs should include verification that the required systems, subsystems, trains, components, and devices that depend on the remaining EDG as a source of emergency 'power are operable before removing an EDG for PM. In addition, positive measures should be providdtl to preclude testing or maintenance activities on these systems, subsystems, trains, components, and devices while the EDG is inoperable.
2.
Removal from service of safety systems and important non-safety equipment, including offsite power sources, should be minimized during the outage of the EDG for PM.
3.
Component testing or maintenance that increases the likelihood of a plant transient should be avoided; plant operation should be stable during the EDG PM.
b.
The condition of offsite sources of electrical power prior to and during the extended EDG outage time have additional importance.
Discuss what considerations should be given to not performing the extended maintenance when the offsite grid condition or configuration is degraded or when adverse or extreme, weather conditions (e.g., high winds, lightning, icing) are expected.
Discuss how planning of the extended EDG maintenance should consider the time needed to complete the maintenance and the ability to accurately forecast weather conditions that are expected to occur during the maintenance.
Discuss what, ifany, contingency plans should be developed to restore the inoperable EDG in the event of unanticipated adverse weather or degraded grid conditions occurring which can significantly increase the probability of losing offsite electrical power.
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