ML043630236
| ML043630236 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  (DPR-077) |
| Issue date: | 12/17/2004 |
| From: | Pace P Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML043630236 (12) | |
Text
Tennessee Valley Authority. Post Office Box 2000, Soddy-Daisy, Tennessee 37384-2000 December 17, 2004 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C. 20555 Gentlemen:
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 SEQUOYAH NUCLEAR PLANT (SQN) -
TRANSMITTAL OF REVISION 1 SIGNIFICANCE DETERMINATION PROCESS (SDP) RISK-INFORMED INSPECTION NOTEBOOK AND INFORMATION REQUEST FOR NEXT REVISION The purpose of this letter is to provide a response to an NRC letter from Mr. Michael Tschiltz to TVA's Mr. Chris Carey dated September 10, 2004.
NRC requested specific plant information for SQN be provided by compact disk (CD) within 30 days of the receipt of their request.
The plant-specific information is included within the enclosed CD.
In accordance with RIN 3150-AH33, "Electronic Maintenance and Submission of Information," Enclosure 1 provides the details of the CD's content. provides SQN's response to NRC's request structured with the enclosed CD.
NRC contacted TVA subsequent to sending the information request to ensure it had been received.
At that time, NRC requested the SQN response be docketed and agreed to extend the 30-day response time.
In accordance with the NRC letter, the enclosed information is considered "Proprietary Information."
Therefore, TVA requests that the enclosed information be withheld from public disclosure in accordance with 10 CFR 2.390(d).
This letter contains no regulatory commitments.
Pnnted on nMCd perw
U.S. Nuclear Regulatory Commission Page 2 December 17, 2004 Please direct questions concerning this issue to me at (423) 843-7170 or J. D. Smith at (423) 843-6672.
Sincerely, ace Manager, Site Licensing and Industry Affairs Enclosures cc: (Enclosures)
Mr. Douglas V. Pickett, Senior Project Manager U.S. Nuclear Regulatory Commission Mail Stop O-7A15 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2739 Mr. Michael Tschiltz, Chief Probabilistic Safety Assessment Branch Mail Stop O10-H4 U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852-2738 Mr. Michael Franovich Probabilistic Safety Assessment Branch Mail Stop 010-H4 U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852-2738
ENCLOSURE 1 TENNESSEE VALLEY AUTHORITY (TVA)
SEQUOYAH NUCLEAR PLANT (SQN)
UNITS 1 AND 2 SEQUOYAH NUCLEAR PLANT (SQN) -
TRANSMITTAL OF REVISION 1 SIGNIFICANCE DETERMINATION PROCESS (SDP) RISK-INFORMED INSPECTION NOTEBOOK AND INFORMATION REQUEST FOR NEXT REVISION Enclosed compact Disc Content FILE NAME l
FILE SIZE -
KB 001_B1 -
Case 1 BEI.xls.PDF l
182 002_Bi -
Case 2 BEI.xls J
198 003 B1 -
BE Decoder.xls 206 004_B2 -
100SEQ.xls l
39 005 B2 and B7 -
Sequence Decoder.pdf 57 006_B3 IEF and B4 CDF.xls 28 007_B5 -
Frontline Event Trees.pdf l
39 008_B5 -
Special Event Trees.pdf J
29 009_B5 -
Support System Event Trees.pdf r 22 010 B6 -
R3 Changes to Model.pdf T
126 011_B7 -
25 seq for each initiator.xls J 314 012_B8 -
System Dependency Tables.pdf 86 013_B9 -
System Notebooks.pdf I
5 014_ClO -HRA Values.pdf 33 015 Cll -
ERCW.pdf l5 5
016_Cll - AOP-M01.pdf 432 017_C12 - RCP Seals.pdf 15 018_C13 -
[019_C14-16 LERF.pdf 37 020_C17 -
HRA HAHH1.pdf J
6 021 D -
Table 1.pdf 16 E1-1
ENCLOSURE 2 TENNESSEE VALLEY AUTHORITY (TVA)
SEQUOYAH NUCLEAR PLANT (SQN)
UNITS 1 AND 2 SEQUOYAH NUCLEAR PLANT (SQN) -
TRANSMITTAL OF REVISION 1 SIGNIFICANCE DETERMINATION PROCESS (SDP) RISK-INFORMED INSPECTION NOTEBOOK AND INFORMATION REQUEST FOR NEXT REVISION NRC REQUEST A.
Comments on Rev. 1 Version of the Notebook Please provide any comments on the Rev. 1 version of the notebook for the Sequoyah Power Station.
Comments on the Rev. 1 version of the notebook and the information requested below will be used to improve and prepare Rev. 2 version of the notebook.
SQN RESPONSE SQN does not have any comments on the Rev. 1 version of the SDP notebook.
NRC REQUEST B.
Updated Plant PRA Information Rev. 1 version of the notebook is based on the information collected during the site visit for benchmarking in January 2003.
For the items marked (*) below, please provide the information if they have been updated since the site visit in January 2003.
An electronic copy for the following is requested.
(1) List of basic event RAW values (preferably in an Excel spreadsheet) for the following:
Case I: internal events and no internal flood and no ISLOCA.
Case II: Full model -
all internal and external events (if available).
Please include a decoder/basic event description list so we can interpret the RAW list.
Include, average maintenance and test unavailabilities in the above cases.
(2) Top 100+ sequences E2-1
- (3) A list of the PRA's initiating event frequencies.
For support systems based initiators (e.g., loss of CCW), please note if the frequency is based on a fault tree or generic data sources (e.g., NUREG/CR-5750).
- (4) CDF values:
(1) internal events CDF value (not including internal flood and no ISLOCA) & model truncation level(s).
(2) total CDF (complete model with external events).
(3) percentage breakdown of total CDF by initiator.
- (5)
Copy of the event trees.
(6) A PRA summary of major insights/recent changes to the model (7) Top 25 sequences for each initiator in the PRA model.
- (8) Updated equipment dependency matrix.
(9) Copy of the system notebooks (optional)
SQN RESPONSE The enclosed compact disc (CD) contains the response to the above requests as follows:
NRC Request SQN Response File Name 001 Bl-Case 1 BEI.xls 002_Bi-Case 2 BEI.xls 003_Bi-BE Decoder.xls 2
004_B2-l0OSEQ.xls 005_B2 and B7 -
Sequence Decoder.pdf 3 and 4 006_B3 IEF and B4 CDF.xls 5
007_5 -
Frontline Event Tree.pdf 008_5 -
Special System Trees.pdf 009_5 -
Support System Event Trees.pdf 6
010 B6 -
R3 Changes to Model.pdf 7
011_B7 -
25 seq for each initiator.xls See SQN Response 2 for sequence decoder 8
012 BB -
System Dependency Table.pdf E2-2
NRC Request SQN Response File Name 9
013_B9 -
System Notebooks.pdf NRC REQUEST C.
Plant-Specific Questions (10) For operator actions credited in the SDP notebook, please provide revised operator action/human error probabilities (HEPs).
(11) In loss of a train of ERCW (e.g., ERCW train A), 2/4 pumps in train B is required to operate.
One pump is normally running, how does the other pump start?
Please describe the action, the time it takes, and provide the emergency procedure for response to loss of a train of ERCW.
(12) Please provide a summary of the PRA models for RCP seal failures and seal leakage.
Please discuss the credit provided for RCS cooldown and depressurization in reducing the seal leakage.
(13) Please describe the scenarios of accidents during SGTR.
Please describe the important operator actions such as SG isolation and equalization.
If possible, please provide the plant procedure for SGTR.
SQN RESPONSE The enclosed CD contains the response to the above requests as follows:
NRC Request SQN Response File Name 10 014_C10 -
HRA Values.pdf 11 015 Cll -
ERCW.pdf 016_Cli -
AOP-M01.pdf 12 017_C12 -
RCP Seals.pdf 13 018 C13 -
SGTR HRA.pdf NRC REQUEST C.1 LERF (14) Hydrogen Ignition System: For the HIS, please provide the maintenance rule performance criteria. How many ignitors (coils) and associated voltage regulators (if installed) have failed in the previous 2 years?
E2-3
(15) For the Tayco ignitors and associated voltage regulators, what failure probabilities or hazard rate, common cause factors, and success criteria are used in the PRA if modeled?
(16) Are the ignitors periodically replaced as part of a life-cycle management or for environmental qualification purposes.
If so, how often are they replaced?
(17) Please provide the HRA evaluation for modeled operator actions related to hydrogen mitigation.
SQN RESPONSE The enclosed CD contains the response to the above requests as follows:
NRC Request SQN Response File Name 14, 15, and 16 019 C14-16 LERF.pdf 17 020 C17 HRA HAHH1.pdf NRC REQUEST D.
Benchmarking Data The following table is a modified version of the table prepared as part of benchmarking of the Rev. 1 notebook.
The intent here is to update the RAW values for the listed components and failed operator actions.
Please note that some additional cases may have been added since the benchmarking in January 2003.
- 1.
Please provide the internal RAW value and the corresponding basic event name based on the latest version of the PRA.
RAW values to be used in this table are based on internal event CDF model excluding internal flooding and ISLOCA (average maintenance and test unavailability case).
- 2.
For clarification of items in the table (components and operator actions), please refer to the SDP notebook.
If a comparable RAW value cannot be obtained for an item, please so indicate and provide additional comments as necessary in the comments column (e.g.,
event listed is not modeled or the event listed is modeled by one or more different events in the PRA).
E2-4
- 3.
For those items where the RAW values include the initiating event contribution, please so indicate in the comments column.
The initiating frequency of support system based initiators (e.g., loss of CCW or loss of a DC Bus) may be modeled using fault trees.
RAW values for items relating to these systems can have contribution due to impact on initiating event frequency.
E2-5
Table 1:
Summary of Benchmarking Results for Sequoyah C::.omponent:~ Out-of-PAW:-
les Udae
....iServicei0 oFald B
ic Ev t Nae Fo Rv 6WCruet OpraEt.....or..
Actio 1Notebok Vle Component 1
One accumulator fails 1.22 2
One MDP of AFW fails 1.36 (MDAFWP-A) 3 TDP of AFW fails 2.37 4
Both MDAFW pumps fail 53.99 (C C F )
5 TDAFW trip and 1.55 throttle valve FTO (FCV 1-51) 6 CVCS centrifugal 2.25 charging pump A fails to run 7
CVCS centrifugal 2.38 charging pump B fails to run 8
MOV FCV 63-25 FTO CCP 1.008 discharge to cold leg 9
HHSI pump A FTS 1.00 10 One RHR pump fails (A) 4.00 11 One RHR pump fails (B) 5.87 12 Containment spray pump 1.00 A or B FTS E2-6
C ponent Out;f-RValud
- a:s:eie.rFi
.iEen:
F o:e.>
- .C o ::::
_Nae
.rom
- e.
RW E
Y Y
Y Y
'.E E E: -
13 Containment 5.58 recirculation sump valve FCV 63-73 (Train B) FTO 14 ECCS LPI/HPI piggy 1.00 back valve FCV 63-8 FTO 15 Failure of RWST level Delta CDF =2.43E-03 to 4/4 Instruments 16 Loss of Main Feedwater 1.11 17 One SG PORV fails to 1.00 open PCV 1-5 18 One MSIV fails to 1.00 close (FCV 1-22) 19 One primary PORV fails 1.195 to open PCV 68-334 20 CCF of both PORVs FTO 2.14 21 One primary P01W fails to close 22 One primary block 1.34 valve fails to close PCV 68-333 23 One primary safety 2.057 valve fails to open (68-563) 24 RHR system fails drop line valve 25 ANSAC fails 1.008 E2-7
C m p n A........
V e
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~~~~~~~.
.............':X..
No Srvie orFa~1 Bsic ven Nam F~om ev.
AW
- 'Comments Operao Action 1: Notebook,: -.':Va-lUes-26 One air compressor of 1.00 IA fails 27 One CCS pump 1A-A FTR 2.1 28 One Standby ERCW pump 1.0 J-A FTS 29 One running ERCW pump fails 30 6.9KV AC bus 1A-A 641.5 fails (safeguard) 31 lH diesel generator 2.57 fails 32 EDG 1A-A FTR without EDG 3.488 recovery 33 EDG 1A-A FTR with EDG recovery 1.374 34 EDG fuel oil transfer 1.008 pump FTS 35 One Vital 125 VDC bus 50.00 1-1 fails 36 125 VDC vital battery
-1.0 fails 37 Failure of a battery charger Operator Actions 38 Operator fails to 1.293 conduct Feed/Bleed 39 Fail to conduct 3.75 emergency boration 40 Fail to initiate HPR 195.94 E2-8
SQN RESPONSE The enclosed CD contains the response to the above requests in the file named 021_D -
Table l.pdf.
E2-9