ML18038B911
| ML18038B911 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/07/1997 |
| From: | Crane C TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-M74386, NUDOCS 9707160021 | |
| Download: ML18038B911 (30) | |
Text
CATEGORY j REGULATO INFORMATION'ISTRIBUTION TEM (RIDS)
C ACCESSION NBR:9707160021 DOC.DATE: 97/07/07 NOTARIZED:
NO FACIL,50-26C" Browns Ferry Nuclear Power Station, Unit 2, Tennessee 50,-296.Browns Ferry Nuclear Power Station, Unit 3, Tennessee AUTH.~VIE AUTHOR AFFILIATION CRANE,,C,:M.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Forwards RAI re multi-unit probabilistic risk assessment.
Detailed chronology of previous correspondence
!N agreements re scope a purpose of multi-unit probabilistic assessment (MUPRA) incjuded.
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.TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
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Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35699-2000 Christopher M. (Chris) Crane Vce President, Browns Ferry Nuclear Plant July 7, 1997 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of Tennessee Valley Authority Docket Nos.
50-260 50-296 BROGANS FERRY NUCLEAR PLANT (BFN) - UNITS 2 AND 3 - RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING MULTI-UNIT PROBABILIST1C RISK ASSESSMENT (TAC NO M74386)
This letter responds to the NRC's June 19, 1997, request for additional information regarding the multi-unit probabilistic risk assessment (MUPRA) for the Browns Ferry Nuclear Plant.
A detailed chronology of the previous correspondence, including the agreements regarding the scope and purpose of the
- MUPRA, are 'included in the enclosure.
In summary, TVA acted in good faith and in full concert with the NRC staff when it agreed in 1992 to voluntarily perform a MUPRA, prior to Unit 3 restart and the resumption of multi-unit operations at BFN, in order to address NRC concerns with the potential safety implications of shared systems.
The NRC's recent request for additional information reflects changes in previous staff positions regarding:
the necessity to perform a MUPRA to satisfy Generic Letter 88-20, and/or
.the scope of work TVA needs to perform in order to address NRC concerns with the potential safety implications of shared systems.
The staff's previously stated positions are described more fully in the enclosure to this letter.
TVA requests that 9707i6002X 970707 POR nOOCK 0S00026O p
PDR 'IIIIIIIIIIIIIIIIIIIII!IIIIIIIIIIIIIIIII
E f
C
U.S. Nuclear Regulatory Commission Page 2
July 7, 1997 these changes in staff position be subjected to:
a systematic and documented analysis of their generic applicability to other multi-unit facilities with shaied
- systems,
~
the determination that there is a substantial increase in the overall protection of the public health and safety or the common defense and security to be derived from these changes in staff positions, and
~
the determination that the direct and indirect costs of implementation will be justified in view of this increased protection.
TVA requests the evaluation of these changes in staff
- position, as well as a staff evaluation of the following policy issues, be completed prior to requesting additional TVA resources be expended in this area.
Regarding the staff concerns about the potential implications of shared
- systems, in summary, it is TVA s position that this issue has been more than adequately addressed.
This issue was resolved with the staff as part of the original licensing of the facility, revisited prior to Unit 3 restart, and neither the MUPRA, nor the subsequently performed individual Unit 2 and Unit 3 PRAs have identified plant vulnerabilities when single or multiple units are in operation.
Regarding the applicability of the Individual Plant Examination (IPE) program to Browns Ferry, it is TVA's position that the IPE program should be considered complete without the expenditure of additional TVA or NRC resources.
The stated NRC use of the IPE results was to obtain reasonable assurance that the licensee has adequately analyzed the plant design and operations to discover instances of particular vulnerability to core melt or unusually poor containment performance given a core melt accident.
The BFN facility has been extensively reviewed by the staff, beginning with an interim reliability evaluation in 1982.
This was followed by the subsequent submittal of the November 20, 1986 BFN PRA and i.ts subsequent NRC audit. It has now been five years since TVA submitted the BFN IPE and over two years since TVA submitted the MUPRA.
Since then, TVA has also performed individual Unit 2 and Unit 3 PRAs and provided them to the Staff.
These analyses have provided the staff with more than reasonable assurance that TVA has adequately analyzed the plant design and operations.
0 0
J
U.S. Nuclear Regulatory Commission Page 3
July 7, 1997 With regard to the MUPRA, it is TVA s position that this analysis represents a historical and superceded
- document, which does not represent the current facility's operational status.
The extensive re-evaluations required to respond to the staff's request for additional information far exceeds the level of detail originally recpxested and will not result in a commensurate practical benefit to TVA or the NRC.
Specifically, the MUPRA bounded three unit operation in accordance with the prior agreements reached with the staff.
TVA's voluntary efforts to improve and update its PRA
- accuracy, usefulness, and insights have resulted in the specific Unit 2 and Unit 3 PRA s discussed above.
Unit 1 is currently defueled and maintained in a lay-up condition.
Therefore, the MUPRA does not accurately reflect the two unit operational status of the facility and its continued review would provide only limited insights at considerable additional cost to TVA.
For all of the reasons expressed
- above, TVA believes that there is no necessity for performing any additional work related to a BFN MUPRA and that a more than adequate basis exists for closing out the IPE program at BFN without the expenditure of additional TVA or NRC resources.
Before requesting TVA to expend any additional resources in this
- area, TVA recpxests that NRC perform an evaluation as described
- above, which addresses the changes from previous staff positions and the policy issues set forth in detail in this response.
If NRC does not agree with the positions expressed by TVA herein, we request a meeting be arranged at NRC's earliest convenience between TVA and NRC senior management to discuss the resolution of these matters.
There are no commitments in this letter. If you have any questions, please contact Tim Abney, Manager of Licensing and Industry Affairs, at.
(205) 729-2636.
Sincerely, C.
M Crane Site
'ce President Enclosure cc:
See Page 4
C
U.S'. Nuclear.Regulatory Commission Page 4
July 7, 1997 cc (Enclosure':
Mr. Mark S. Lesser, Branch Chief U.S. Nuclear Regulatory Commission Region II 61 Forsyth Street, S.W.
Atlanta, Georgia 30303 NRC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road
- Athens, Alabama 35611 Mr:. J.
F. Williams, Project Manager
- U.S. Nuclear Regulatory Commission One White Flint, North 1'1555 Rockvi:lie Pike Rockville, Maryland 20852 Mr. R. P.
2immerman.
,U.S. Nuclear Regulatory Commission One Wh'ite Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. S. J. Collins U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland'0852
ENCLOSURE BROGANS FERRY NUCLEAR PLANT - UNITS 2 AND 3
RESPONSE
TO REQUEST FOR ADDITIONAL INFORMATION REGARDING MULTI-UNITPROBABILISTZC RISK ASSESSMENT BACKGROUND Generic Letter 88-20, "Individual Plant Examination for Severe Accident Vulnerabilities" (Reference 1), dated November 23, 1988, requested all licensees perform the following for each plant:
1.
Perform a systematic examination to identify any plant specific vulnerabilities to severe accidents, 2.
Identify and review proposed plant improvements (design changes and changes to operating procedures, maintenance, surveillance, training, or staffing),
3.
Decide which of these improvements will be implemented and their schedule, and 4.
Report the results to the Commission.
The, stated NRC use of the IPE results was to obtain reasonable assurance that the licensee has adequately analyzed the plant design and operations to discover instances of particular vulnerability to core melt or unusually poor containment performance given a core melt accident.
Further, the NRC was to assess whether the conclusions the licensee draws from the IPE regarding changes to the plant,
- systems, components, or accident management procedures were adequate.
In response, by letter dated October 30, 1989 (Reference 2),
TVA committed to complete a Level I PRA and containment analysis for Browns Ferry by September 1,
1992.
In August of 1990 (Reference 3),
NRC noted that the three units at BFN share important safety systems.
NRC expressed a concern with the potential safety implications of shared systems in the various operating modes of the BFN units (e.g., All three units operating, Units 1 and 2 operating with Unit 3 shutdown, etc.).
NRC requested TVA provide:
1.
Dependency tables for Units 1 and 3 similar to that provided for Unit 2, and 2.
Expanded PRAs for Units 1 and 3 that evaluate the entire site as a whole, taking into account the risk significant combinations of unit operational status.
II
TVA responded to this request on October 12, 1990
'(Reference 4).
TVA committed to submit dependency matrices prior to the restart of Unit 3, which assumed Units 2 and 3
are operational.
TVA also committed to submit. dependency matrices prior to the restart of Unit 1, which assumed Units 1, 2, and 3 are operational.
TVA declined to pursue the development of multi-unit PRAs at that time for the following reasons:
~
BFN does not significantly rely on safety systems which are specific to one unit to achieve and maintain safe shutdown of another unit.
~
The Unit 2 dependency matrices did not identify any instances of cross-train dependencies that. would compromise the analyzed safety-related systems.
~
The subject of unit sharing and interactions was reviewed at the time of the original licensing of BFN.
~
Generic Letter 88-20 requested licensees perform a single unit PRA. It did not request licensees of multiple unit sites perform individual PRAs for each plant at a multi-unit site or address the effect of shared systems between units.
In response to Generic Letter 88-20, TVA committed to perform a Level 1 PRA and limited containment analysis, which assumed Unit, 2 in operation and Units 1 and 3 shutdown.
In June 1991 (Reference 5),
NRC acknowledged that the performance of these expanded PRAs was not required to fulfillGeneric Letter 88-20.
Furthermore, the staff concluded that the information to be supplied by. TVA appeared to be in accordance with the information currently requested by Generic Letter 88-20 and its supplements.
However, the staff continued to encourage TVA to perform the expanded PRAs for BFN Units 1 and 3.
TVA and NRC met on September 6,
1991 to discuss the NRC's request (Reference 6).
During this meeting, the staff expressed concerns regarding the number of shared systems at BFN and the control of these systems to ensure availability.
In February 1992 (Reference 7),
TVA provided a list of the systems shared between the BFN units and a description of their shared functions.
TVA reviewed these shared systems and identified ten systems whose ability to reliably perform their safety function could be challenged due to the impact of system sharing.
The most limiting configuration for the ten shared systems occurs when all three units are in operation.
Loss of offsite power and loss of plant air are the two initiating events that directly result in the shutdown of all three units.
Therefore, TVA committed to E-2
il
perform an expanded PRA, to address the change in Unit 2
'core melt frequency associated with all three units in operation.
This analysis would address the impact of the ten critical shared systems during a loss of offsite power and loss of plant air transients.
TVA stated that it intended to submit a summary report to NRC prior to the restart of Unit 3.
- However, TVA did not consider completion of this,work to be a restart prerequisite.
NRC's review of the TVA approach for addressing multi-unit dependencies was provided in July 1992 (Reference 8).
The Staff agreed that this report was not a prerequisite for the restart of Unit 3 and stated that TVA's approach appeared to be responsive to staff concerns raised in previous correspondence,.
in that inter-unit dependencies through shared systems should be considered in analyzing severe accident sequences.
However, the Staff requested TVA to provide formal notification if the completion date should slip beyond the end of 1993.
In response to Generic Letter 88-20, TVA completed and submitted the single unit BFN PRA on September 1,
1992 (Reference 9).
When TVA was initially responding to the hardened vent issue, NRC requested TVA in an April 1990 teleconference to incorporate the hardened vent into the PRA.
During development of the initial BFN PRA frontline event trees, it was recognized that the hardened wetwell vent would be implemented for BFN Unit 2 during the Unit 2 Cycle 6 refueling outage.
Since this outage would occur following submittal of the BFN single unit PRA (September 1992),
TVA decided not to model this feature in the initial version of the BFN PRA model.
As discussed in Reference 10, TVA committed to incorporate the hardened vent into the next update of the BFN PRA.
As discussed in Reference 11, TVA committed to summarize the impact of the hardened vent as part of the multi-unit PRA submittal.
On December 2,
1993 (Reference 12),
TVA provided the Staff with an updated schedule for the submittal of the multi-unit PRA.
At the time of this letter, the Unit 3 design effort had progressed to the point where the multi-unit PRA work could be supported.
Based on the forecasted progression of the Unit 3 design work, TVA provided a January 18, 1995 scheduled submittal date for the multi-unit PRA.
The NRC Safety Evaluation Report (Reference 13) was issued on the single unit BFN PRA on September 28, 1994.
In the Safety Evaluation, the Staff requested TVA to address the feasibility of evaluating the potential benefit of two containment performance improvement items as part of the multi-unit PRA.
Due, in part, to this request from NRC to expand the scope of the multi-unit PRA, on January 19, 1995 E-3
0 II J
4'l'
(Reference 14),
TVA rescheduled the submittal date for the
'multi-unit PRA to April 14, 1995.
TVA submitted the BFN MUPRA on April 14, 1995 (Reference 15).
In September
- 1995, NRR personnel participated in a special, announced inspection in the area of facility control over activities which had been identified as significant to overall plant risk as reported in TVA's MUPRA (Reference 16).
The purpose of this inspection was to evaluate the facility's performance in operations, engineering, and maintenance of selected risk-related components and activities.
The inspectors found that the facility's performance in operations, training, engineering, and maintenance was adequate with respect to items identified as important to risk by the.
MUPRA.
Within the areas inspected, there were no adverse findings related to multi-unit operation.
In SECY-95-264, dated November 1, 1995 (Reference 17), this Inspection Report is cited to the Commissioners as the basis for considering the PRA issue closed for the basis of Unit 3 restart.
Subsequently, in a letter from Mr. Taylor on June 21, 1996, the staff concluded that unit operations have demonstrated the ability of the BFN staff to conduct dual unit operations at. power and diverse outage/power conditions simultaneously (Reference 18).
TVA's MUPRA bounded three unit operation.
As stated in TVA's April 16, 1996 letter (Reference 19),
TVA has not reached a decision on the long-term operational status of Unit 1.
Unit 1 is currently defueled and maintained in a lay-up condition.
There are no current plans for equipment refurbishment or recovery activities.
NRC has published draft NUREG-1560, "Individual Plant Examination Program:
Perspectives on Reactor Safety and Plant Performance" (Reference 20), which summarizes the results of the Individual Plant Examination Program conducted in response to NRC Generic Letter 88-20.
The Nuclear Energy Institute position was provided to the Staff on May 9, 1997 (Reference 21).
In summary, NUREG-1560 provides the appropriate basis for closure of the IPE process.
As is the case for many other utilities, TVA continues to utilize, update and improve its plant specific PRA s.
TVA currently has a Unit 2 specific PRA that reflects Unit 3 in operation and a Unit 3 specific PRA that reflects Unit 2 in operation.
By letter dated February,25, 1997, the NRC requested copies of any updated material to the initial IPE submittal (Reference 22).
These next generation PRA's were provided to NRC and, as stated in Reference 21, were to be E-4
I
made available in the Public Document Room by the Staff.
As
~ documented in the Maintenance Rule Inspection Report, dated May 21, 1997 (Reference 23):
~
Licensed operators understanding of the risk matrix for removal of equipment from service was good.
~
The licensee's overall quantitative approach to performing risk ranking for SSCs in the scope of the Maintenance Rule using the PRA approach was adequate.
~
PRA procedures in support of the Maintenance Rule were adequate.
~
The risk matrix and associated procedure for removal of equipment from service was considered good.
II'ISCUSSION TVA acted in good faith and in full concert with the NRC staff when it agreed in 1992 to voluntarily perform a MUPRA, prior to Unit 3 restart and the resumption of multi-unit operations at BFN, in order to address NRC concerns with the potential safety implications of shared systems.
The scope of TVA's analysis was clearly defined in advance.
The NRC staff agreed with TVA that the performance of the MUPRA was not required to fulfillGeneric Letter 88-20 and concluded that the information to be supplied by TVA appeared to be responsive to staff concerns raised in previous correspondence.
When TVA submitted the MUPRA, the scope of the analysis considered significantly more than the original commitment required.
The NRC's recent request for additional information reflects changes in previous staff positions regarding:
~
the necessity to perform a MUPRA to satisfy Generic Letter 88-20, and/or
~
the scope of work TVA needs to perform in order to address NRC concerns with the potential safety implications of shared systems.
TVA requests that these changes in staff position be subjected to:
~
a systematic and documented analysis of their generic applicability to other multi-unit facilities with shared
- systems, E-5
ly v
4 I
~
the determination that there is a substantial increase in the overall protection of the public health and safety or the common defense and security to be derived from these changes in staff positions, and
~
the determination that the direct and indirect costs of implementation will be justified in view of this increased protection.
TVA requests the evaluation of these changes in staff
- position, as well as a staff evaluation of the following policy issues, be completed prior to requesting additional TVA resources be.expended in this area.
Regarding the staff concerns about the potential implications of shared systems, it is 'TVA's position that this issue has been more than adequately addressed.
- First, a thorough discussion of shared structures, systems and components is contained in Appendix F on the Updated Final Safety Analysis Report.
Issues regarding shared systems were reviewed by the staff and resolved as part of the licensing of the facility.
- Second, as discussed in TVA s February 12,
- 1997, response to the NRC's October 9,
- 1996, 10 CFR 50.54(f) request for information regarding the
- adequacy, availability, and control of design bases information, TVA performed a Design Basis Verification Program (DBVP) to ensure the plant configuration satisfies the design basis and is in conformance with TVA licensing commitments.
Third, as discussed
- above, TVA voluntarily performed a
MUPRA to address NRC concerns with the potential safety implications of shared systems.
In September
- 1995, NRR personnel participated in a special, announced inspection in the area of facility control over activities which had been identified as significant to overall plant risk as reported in TVA's MUPRA.
The purpose of this inspection was to evaluate the facility's performance in operations, engineering, and maintenance of selected risk-related components and activities.
The inspectors found that the facility's performance in operations, training, engineering, and maintenance was adequate with respect to items identified as important to risk by the MUPRA.
Within the areas inspected, there were no adverse findings related to multi-unit operation.
In SECY-95-264, dated November 1,
1995, this NRR review is cited to the Commissioners as the basis for considering the PRA issue closed for the basis of Unit 3 restart.
Fourth, in a letter from Mr. Taylor on June 21, 1996, the staff concluded that unit operations have demonstrated the ability of the BFN staff to conduct dual unit operations at power and diverse outage/power conditions simultaneously.
The transition to dual-unit operations has been successfully completed.
Finally, neither the MUPRA, nor the subsequently performed E-6
Ib il
individual Unit 2 and Unit.
3 PRAs have identified plant
'ulnerabilities when single or multiple units are in operation.
Regarding the applicability of the Individual Plant Examination (IPE) program to Browns Ferry, it is TVA's position that the IPE program should be considered complete without the expenditure of additional TVA or NRC resources.
It has been nine years since the staff requested licensees perform a systematic examination to identify any plant specific vulnerabilities to severe accidents and identify any proposed plant improvement.
The stated NRC use of the IPE results was to obtain reasonable assurance that the licensee has adequately analyzed the plant design and operations to discover instances of particular vulnerability to core melt or unusually poor containment performance given a core melt accident.
The BFN facility has been extensively reviewed by the staff, beginning with NUREG/CR-2802, "Interim Reliability Evaluation Program Analysis of the Browns Ferry, Unit 1 Nuclear Plant," in 1982.
This was followed by the subsequent submittal of the November 20, 1986 BFN PRA and its subsequent NRC audit. It has been five years since TVA submitted the BFN IPE and over two years since TVA submitted the MUPRA.
Since then, TVA has also performed individual Unit 2 and Unit 3 PRAs and provided them to the Staff.
These subsequent PRA addressed many of the staff concerns identified during their September 1995 inspection.
Additionally, NRC has verified TVA s effective utilization of the current generation PRA's as part of the Maintenance Rule Inspection.
These analyses have provided the staff with more than reasonable assurance that TVA has adequately analyzed the plant design and operations.
Nith regard to the MUPRA, it is TVA s position that this analysis represents a historical and superceded
- document, which does not represent the current facility's operational status.
The extensive re-evaluations required to respond to the staff's request for additional information far exceeds the level of detail originally requested and will not result in a commensurate practical benefit to TVA or the NRC.
Specifically, the MUPRA bounded three unit operation in accordance with the prior agreements reached with the staff.
TVA's voluntary efforts to improve and update its PRA
- accuracy, usefulness, and insights have resulted in the specific Unit 2 and Unit 3 PRA s discussed above.
As stated in TVA's April 16, 1996 letter, TVA has not reached a
decision on the long-term operational status of Unit 1.
Unit 1 is currently defueled and maintained in a lay-up condition.
There are no current plans for equipment E-7
II l'
refurbishment or recovery activities.
Therefore, the MUPRA does not accurately reflect the two unit operational status of the facility and its continued review would provide only limited insights at considerable additional cost to TVA.
With regard to the overall IPE program, NRC has published draft NUREG-1560, "Individual Plant Examination Program:
Perspectives on Reactor Safety and Plant Performance,"
which summarizes'he results of the Individual Plant Examination Program conducted in response to NRC Generic Letter 88-20.
TVA endorses the Nuclear Energy Institute position, which was provided to the Staff on May 9, 1997.
In summary, NUREG-1560 provides the appropriate basis for closure of the IPE process.
III'ONCLUSIONS For all of the reasons expressed
- above, TVA believes that there is no necessity for performing any additional work related to a BFN MUPRA and that a more than adequate basis exists for closing out the IPE program at BFN without the expenditure of additional TVA or NRC resources.
Before requesting TVA to expend any additional resources in this
- area, TVA requests that NRC perform an evaluation as described
- above, which addresses.
the changes from previous staff positions and the policy issues set forth in detail in this response.
If NRC does not agree with the positions expressed by TVA herein, we request a meeting be arranged at NRC's earliest convenience between TVA and NRC senior management to discuss the resolution of these matters.
REFERENCES NRC letter to All Licensees Holding Operating Licenses and Construction Permits, dated November 23, 1988, Individual Plant Examination for Severe Accident Vulnerabilities 10 CFR 50.54(f)
(Generic Letter 88-20) 2 ~
TVA letter to NRC, dated October 30, 1989,, Proposed Program in Response to Generic Letter.88-20 Individual Plant Examination (IPE) for Severe Accident Vulnerabilities 3 ~
4.
NRC letter to TVA, dated August 13,
- 1990, PRA Concerns Regarding Operation of Browns Ferry, Units 1 and 3
TVA letter to NRC, dated October 12,
- 1990, PRA Concerns Regarding Operation of Browns Ferry, Units 1 and 3
E-8
5.
6.
7 ~
8.
9 ~
10.
12.
13
~
NRC letter to TVA, dated June 28, 1991, Individual Plant Examination for Severe Accident Vulnerabilities (Generic Letter 88-20),
Browns Ferry Nuclear Plant, Units 1, 2, and 3
NRC letter to TVA, dated November 1,
- 1991, Summary of the September 6,
1991 Meeting with TVA Regarding the Appropriate Methodology for Conduction Individual Plant Examinations (IPE) at Multi-Unit Sites TVA letter to NRC, dated February 7,
- 1992, Expanded Probabilistic Risk Assessment (PRA) Considering Operation of Browns Ferry, Units 1 and 3
NRC letter to TVA, dated July 22,
- 1992, TVA Approach for Addressing Inter-Unit Dependencies as part of the Individual Plant Examination for the Browns Ferry Nuclear Plant TVA letter to NRC, dated September 1,
- 1992,
Response
to Generic Letter (GL) 88-20 "Individual Plant Examination for Severe Accident Vulnerabilities 10 CFR 50.54(f)"
TVA letter to NRC, dated May 1, 1990, Probabilistic Risk Assessment (PRA) and Emergency Operating Procedure (EOP)
TVA letter to NRC, dated December 23,
- 1993,
Response
to Request for Additional Information Regarding the Individual Plant Examination (IPE)
TVA letter to NRC, dated December 2,
- 1993, Expanded Probabilistic Risk Assessment (PRA)
NRC letter to TVA, dated September 28, 1994, Individual Plant Examination Submittal for Internal Events 14.
TVA letter to NRC, dated January 19,
- 1995, Schedule for Submittal of the Expanded (Multi-Unit) Probabilistic Risk Assessment (PRA) and Portions of the Individual Plant Examination of External Events 15.
16.
17.
TVA letter to NRC, dated April 14, 1995, Multi-unit Probabilistic Risk Assessment (PRA)
NRC letter to TVA, dated October 10,
- 1995, NRC Inspection Report Nos. 50-259/95-49, 50-260/95-49, and 50-296/95-49 NRC Internal Memorandum, from James M. Taylor, Executive Director for Operations for The Commissioners, dated November, 1, 1995, Restart of the Browns Ferry Nuclear Plant Unit 3 E-9
ll r
18.
19.
NRC letter from, James.
M. Taylor, to TVA, dated
'une 21, 1996, in regards to the June 4-5, 1996 NRC.Senior Managers Meeting TVA letter to NRC, dated April 16, 1996, in regards to removal of BFN Units 1 and 3 from the Problem Plant List 20.
21 22
'3.
Draft NUREG-1560 Individual Plant Examination Program:
Perspectives on Reactor Safety and Plant Performance, 62'ederal Register
- 13198, dated March 19, 1997 NEI letter to NRC, dated'ay 9,
1997, Industry Comments on Draft NUREG-1560 Individual Plant Examination Program:
Perspectives on Reactor Safety and Plant Performance, (62 Federal Register
- 13198, dated March 19, 1997)
Opportunity for Public Comments NRC letter to TVA, dated February 25, 1997, Maintenance Rule Baseline Team Inspection (NRC Inspection Report Nos. 50-259/97-04, 50-260/97-04, and 50-296/97-04)
NRC letter to TVA, dated May 21,
- 1997, NRC Inspection Report 50-259/97-04, 50-260/97-04, and 50-296/97-04 E-10
!I.
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