ML050880412
| ML050880412 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 03/23/2005 |
| From: | Matthews W Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 04-272A | |
| Download: ML050880412 (16) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 March 23, 2005 U.S. Nuclear Regulatory Commission Serial No.
04-272A Attention: Document Control Desk NLOS/GDM RD Washington, D.C. 20555 Docket No.
50-281 License No. DPR-37 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT 2 ASME SECTION Xi FOURTH INSERVICE INSPECTION (IS0) INTERVAL UPDATE RISK INFORMED INSERVICE INSPECTION (RH-ISI) PROGRAM RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION In a letter dated May 13, 2004 (Serial No.04-272), Virginia Electric and Power Company (Dominion) submitted the Surry Unit 2 RI-ISI program pursuant to 10 CFR 50.55a(a)(3)(i) for the ASME Section Xl fourth ISI interval. In that submittal we noted that new information had been incorporated into the RH-ISI analysis as part of the "living program," specified by the Westinghouse Owners Group (WOG) RI-ISI methodology documented in WCAP-14572, Rev. 1-NP-A.
The new information was limited to changes to the Probabilistic Risk Assessment (PRA) model and deterministic information supplied to the expert panel since the last evaluation. Failure probability information for Surry Unit 2 remained unchanged.
During staff review of the Surry Unit 2 RI-ISI Program submittal, the NRC determined that additional information was necessary to complete their review.
On January 3, 2005, the NRC Surry Project Manager provided four questions associated with the information provided in Dominion's May 13, 2004 submittal. Dominion has reviewed the questions and prepared responses to resolve each question. The NRC's questions and Dominion's responses are provided in the attachment.
If you have any questions or require additional information, please contact Mr. Gary D. Miller at (804) 273-2771.
Very truly yours, aoke z4Z William R. Matthews Senior Vice President-Nuclear Operations Enclosure Commitments made by this letter: None
SN 04-272A Docket No. 50-281 Page 2 of 2 cc:
U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23 T85 Atlanta, GA 30303-3415 Mr. S. R. Monarque U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 8H12 Rockville, MD 20852 Mr. N. P. Garrett NRC Senior Resident Inspector Surry Power Station Mr. R. A. Smith Authorized Nuclear Inspector Surry Power Station
Enclosure ASME Section Xl Fourth ISI Interval Update Risk Informed Inservice Inspection (RI-ISI) Program Response to NRC Request for Additional Information Surry Power Station Unit 2 Virginia Electric and Power Company (Dominion)
Enclosure ASME Section Xi Fourth ISI Interval Undate Risk Informed Inservice Inspection (RI-ISI) Program Response to NRC Request for Additional Information The following four questions were received from the NRC Surry Project Manager on January 3, 2005, and are associated with Dominion's May 13, 2004 submittal (Serial No.04-272) of the RI-ISI program for Surry Unit 2.
- 1. For Relief Request R-1, have there been any changes to the number or type of inspections being performed on the three piping segments since Vepco's RI-ISI program was approved on January26, 2001? If so, please explain the changes.
Response
As reported in Dominion's May 13, 2004 submittal, three segments are addressed by Relief Request R-1.
For these segments, no changes to the number or type of inspections is being requested from the previously approved relief request on socket welds for the Surry Unit 2 RI-ISI program.
- 2. Your submittal dated May 13, 2004 states that Surry Unit 2 does not include Alloy 600 within the piping welds of the RI-ISI program. In order to clarify this statement, the staff would like to know if there are any other disimiliar metal welds within your Ri-ISI program that would contain Alloy 82/182 filler metal?
Resgonse:
Certain Surry Unit 2 welds have Alloy 82/182 filler metal. The RTD bypass line elimination design change implemented on Surry Unit 2 installed Alloy 600 thermowells.
Socket welds were used to attach the thermowells to the existing stainless steel scoops inserted into the Reactor Coolant System (RCS) loop piping.
These socket welds are either 1" or 1.5" in size. The welds are 82/182 filler metal.
These welds are periodically examined as part of the augmented Boric Acid Corrosion Control (BACC) program and the corresponding visual inspection program. The welds (12 total) are grouped into three RI-ISI segments based upon the RCS loop location. The original submittal had not identified these locations as having this type material. Had the 82/182 material been previously identified, the Expert Panel would have considered these segments to be high safety significant (HSS), and, going forward, these segments will be considered as such. An updated summary chart is attached (Attachment 1) that indicates the increase in HSS Page 1 of 5
Serial No. 04-272A Docket 50-281 segments within the augmented inspection program due to the incorporation of these welds. The examinations required on these segments will be based upon the augmented visual inspectibn program already established for this material [reference WCAP-14572 Rev.1-NP-A, page 168, Region 1, and Dominion letter to the NRC dated January 5, 2004 (Serial No. 02-689A)]. Additionally, in a letter to the NRC dated January 31, 2003 (Serial No.02-689), Dominion noted that the channel head drains on the steam generators also contain Alloy 82/182 welds. These locations were not modeled in the RI-ISI process as they are of such a size as to have no conditional consequence (i.e., 3/8"). They are, however, included in the augmented visual inspection program as discussed in Dominion's January 31, 2003 letter. No other locations have been identified as having Alloy 82/182 filler metal.
- 3. Are there any piping segments in the Surry Unit 2 RI-ISI program that include piping of different diameters? If so, how were the failure frequencies estimated for these segments? How does the methodology for determining the failure frequencies comport with the methodology described on page 71 of WCAP-14572, Rev. 1-NP-A?
Response
The Surry Unit 2 RH-ISI program includes segments with piping of different diameters.
The engineering team originally based their failure probabilities for multiple line size piping on a line size not necessarily the most limiting, but based it upon the location more representative of the postulated mechanism being considered. A total of twenty-six (26) segments out of 139 segments were found to be grouped with multiple line sizes. Of these 26 segments, eight had no conditional consequence given a failure, and six segments appropriately used the most limiting failure probability for pipe line size.
The remaining twelve (12) segments have a more limiting failure probability assigned based upon the use of a different line size in the segment. Page 71 of WCAP-14572, Rev. 1-NP-A, requires that the inputs used should be the most limiting or bounding for the entire segment. Dominion's use of line sizes, which do not give the most limiting or bounding results would be considered a deviation from the process.
This oversight is attributed to initial training, which did not emphasize the multiple line size impact on failure probability; and is similar to the multiple line size segment issue identified at other Westinghouse Owners Group methodology plants by the NRC.
As such, the 12 segments require new failure probabilities. New failure probabilities have been re-calculated based upon the most limiting line size. A sensitivity study was conducted to determine the impact of the failure probability change on the risk ranking. provides a summary of the new failure probabilities used in the sensitivity study. The new calculated failure probabilities for segments RC-058 and RC-059 have increased by about two orders of magnitude. The increase was due to the failure probability being based upon a socket weld, rather than a butt weld as originally evaluated. This caused these two segments to become HSS from medium safety significant (MSS) segments based on RRW (Risk Reduction Worth). The Page 2 of 5
Serial No. 04-272A Docket 50-281 Expert Panel had previously noted a high stress concern and water solid pressurizer concern for these segments during the third inservice inspection interval. These concerns were retained by the Expert Panel for the fourth inservice inspection interval update, and the Panel consequently classified these segments as HSS even though the original quantitative values for RRW were of medium safety significance.
As such, there is no impact on the Expert Panel's selections for these two segments.
The postulated failure mechanism for these segments is vibratory fatigue, which requires the visual (VT-2) examination method and does not require the Perdue Model to determine examination sampling requirements.
The original quantitative RRW values for segment RC-055 were below 1.001, which is low safety significant (LSS). With the new failure probability, the quantitative RRW of segment RC-055 became 1.0011 [Large Early Release Frequency (LERF) with Operator Action only], which is a very minor increase just inside the MSS range.
This new value also matched the initial third inservice inspection interval quantitatively, where the segment was also categorized as MSS (LERF only). The Expert Panel for the initial RI-ISI program unanimously voted the segment LSS.
Based on the initial Expert Panel's decision to vote segment RC-055 LSS under the same circumstances, it was determined that the safety significance of RC-055 could justifiably remain as LSS.
With segments RC-058 and 059 increasing in RRW with their revised failure probabilities, the relative ranking process caused segments ECC-005, 006, and 007 to become LSS from MSS; however, the Expert Panel had a concern with the single check valve separating these segments from the HSS RCS segments and consequently classified these segments HSS regardless of their quantitative results.
The shift from MSS to LSS does not affect the Expert Panel's decision on these segments.
Overall effects of the new failure probabilities did not alter the selections made by the Expert Panel. Attachment 3 shows the comparison between the revised fourth inservice inspection interval RI-ISI submittal and the sensitivity study with the 12 new failure probabilities.
The range of RRW values for each safety significant class is as follows:
Low Safety Significant (LSS):
RRW s 1.001 Medium Safety Significant (MSS): 1.001 < RRW < 1.005 High Safety Significant (HSS):
RRW Ž 1.005 The above criteria are used to classify the segments listed in Attachment 3.
- 4. Section 4 of your original RI-IS! submittal dated April 27, 2000, states that, as a minimum, risk ranking of pipe segments will be reviewed and adjusted on an ASME period basis. Your submittal of May 13, 2004, states that the change in risk analysis was re-performed to compare the original Section Xl program with the revised fourth Page 3 of 5
Serial No. 04-272A Docket 50-281 interval RI-ISI program.
You also stated that this resulted in an additional visual VT-2 exam being added to the program.
Were any inspections discontinued or relocated as a result of this comparison? If so, please provide an estimate of the change in risk. Also confirm that the total change in risk and system level change in risk estimates for the proposed fourth interval program are within the acceptance guidelines of WCAP-14572, Rev. 1-NP-A?
Response
No inspections were removed from the RI-ISI program nor were previous inspections relocated to new segments as a result of the new change in risk evaluation. The change in risk evaluation was performed for the fourth inservice inspection interval to ensure risk neutrality of the program as the PRA model has been updated since the original implementation of the RH-ISI program. The initial change in risk evaluation, which only included the segments that were selected by the Expert Panel, revealed that the total risk increased slightly in the process of switching from ASME Section Xl ISI to RI-ISI.
The dominant system contributor for Core Damage Frequency (CDF) without (w/o) and with (w/) Operator Action is the RCS. The dominant system contributor for LERF w/o and w/ Operator Action is also the RCS.
There were two segments, RC-046 and RC-048, which were added to.the third inservice inspection interval to achieve risk neutrality for the previous RI-ISI program. In addition to these two segments, one additional segment (RC-024) was added to the fourth inservice inspection interval RI-ISI program to ensure at least risk neutrality or better. The addition of segment RC-024 resulted in adding an additional VT-2 exam to the program as compared to the third inspection interval.
The results of adding the three piping segments to the RI-ISI program are provided in the tables below:
Fourth Interval Final Delta Risk Comparison - CDF Without Operator A tion System ASME RH-ISI RI-ISI Delta Criterion for Acceptable Section XI ISI Results Percent if Risk Acceptable Increase Results Contribution Increase Increase ACC 2.39E-12 3.03E-12 0.00%
6.47E-13 1.OOE-08 Yes CH 1.32E-07 1.32E-07 6.92%
1.OOE-08 ECC 1.02E-09 7.40E-10 0.04%
RC 1.78E-06 1.78E-06 93.04%_
RH 5.50E-14 3.47E-13 0.00%
2.92E-13 1.00E-08 Yes TOTAL 1 1.91 E-06 1.91 E-061 I
Page 4 of 5
Serial No. 04-272A Docket 50-281 Fourth Interval Final Delta Risk Comparison - CDF With Operator Action System ASME RI-ISI RI-ISI Delta Criterion for Acceptable Section XI ISI Results Percent if Risk Acceptable Increase Results Contribution Increase Increase ACC 1.76E-12 2.24E-12 0.00%
4.79E-13 1.OOE-08 Yes CH 1.32E-07 1.32E-07 6.93%
1.OOE-08 ECC 1.02E-09 7.40E-10 0.04%
RC 1.78E-06 1.78E-06 93.03%
RH 5.50E-14 3.47E-13' 0.00%
2.92E-13 1.OOE-08 Yes TOTAL
[
1.91 E-061 1.91 E-061 I
I Fourth Interval Final Delta Risk Comparison - LERF Without Operator Action System ASME RI-ISI RI-ISI Delta Criterion for Acceptable Section XI ISI Results Percent if Risk Acceptable Increase Results Contribution Increase Increase ACC 6.26E-13 7.93E-13 0.00%
1.67E-13 1.OOE-08 Yes CH 1.74E-09 1.74E-09 7.45%
1.OOE-08 ECC 4.64E-13 3.36E-1 3 0.00%
RC 2.16E-08 2.16E-08 92.54%
RH 4.78E-14 3.25E-131 0.00%
2.77E-13 1.OOE-08 Yes TOTAL 2.34E-08 2.34E-08l I
I Fourth Interval Final Delta Risk Comparison - LERF With Operator Action System ASME RI-ISI RI-ISI Delta Criterion for Acceptable Section XI ISI Results Percent if Risk Acceptable Increase Results 4 Contribution Increase Increase ACC I
6.07E-16 7.72E-166 0.00%
1.65E-16 1.OOE-08 Yes OH 1.74E-09 1.74E-09 7.45%
1.00E-08l 1
ECC 4.64E-13 3.36E-13 0.00%
RC I
2.16E-08 2.16E-081 92.54%
1 _
I RH 4.78E-14 3.25E-13l 0.00%1 2.77E-131 1.OOE-081 Yes lTOTAL I 2.34E-081 2.34E-08l I
I I
I ACC:
CH:
ECC:
RC:
RH:
Safety Injection (SI) Accumulator System Chemical and Volume Control System SI Emergency Core Cooling System Reactor Coolant System Residual Heat Removal System As demonstrated in the above tables, the total change in risk and system level change in risk for the proposed fourth inservice inspection interval program are within the acceptance guidelines of WCAP-14572, Rev. 1-NP-A.
Page 5 of 5
Serial No. 04-272A Docket 50-281 STRUCTURAL ELEMENT SELECTION RESULTS AND COMPARISON TO ASME SECTION Xl 1989 EDITION REQUIREMENTS System Number of High Safety Significant.
Segments (No. of HSS Segments in Augmented Program /
Total No. of Segments in Augmented Proaram)
Degradation Mechanism(s)
Class ASME Code Category Weld Count' Previous ASME Xl Examination Volumetric &
Surface or Surface Only 3rd Interval RI-ISI 4thl Interval RI-ISI Butt ISocket Y
I.
SES Matrix Region Number of Exam Locations SES Matrix Region Number of Exam Locations ACC 0
TF Class 1 B-J 34 0
10 0
0 CH 6 (0)
TF, VF Class 1 B-J 83 182 70 1 a 6a la 6a ECC 7 (0)
TF, Class 1 B-J 70 157 45 la,lb 7b + 18c l a,lb,3 I+ 12c +
Stratification 6.d RC 38(6/6)
TF, VF, Class 1 B-F 18 0
18 la, lb, 2 6c la,lb,2 6c Striping/
B-J 246 285 166 12a+ lb +
12a+25 +
Stratification, 26c 26c SOC RH 0
TF Class 1 B-J 19 0
4 0
0 Class 1 B-F 18 0
18 6c 6c B-J 452 624 295 18a + 8b +
18a + 3 +
TOTAL 51(6/6) 44c 38c + 6_d Total 470 624 313 18a + 8" +
1 3" +
50C 4 4 c + 6 d Page 1 of 2
Serial No. 04-272A Docket 50-281 Notes:
- 1) Section Xl nonexempt welds only (> 1 inch) a) VT-2 examination of segment due to failure mechanism postulated as vibration fatigue.
b) Scheduled VT-2 examination of segment socket welds.
c) HSS scheduled volumetric examinations.
d) LSS scheduled volumetric examinations.
ACC - Safety Injection piping associated with the accumulators CH - Chemical and Volume Control piping ECC - High Pressure and Low Pressure Safety Injection common header piping RC - Reactor Coolant piping RH - Residual Heat Removal piping TF - Thermal Fatigue (normal heat-up and cool-down, with and without snubber malfunctions)
VF - Vibratory Fatigue SCC - Stress Corrosion Cracking Page 2 of 2 MawPni Final Prnhnhilitu 1FP1 Qi ilmmorv Is Required LL If Conditional FP a Change Consequence is 0 LL FP from the Segment(s) with then no FP Pipe Size Limiting Large LL FP Used in Required to be Original Multiple Line Sizes Required NPS Leak (LL) FP Original Submittal Used Submittal
% CHANGE CH-001, 002. 003 Not 0 2
2.91 E-03 NO NO CH-001, 002. 003 Not 0 1.5 5.71 E-03 YES YES NO CH-001, 002. 003 Not 0 0.75 5.09E-03 NO NO CH-004, 005, 006 0
2 N/A N/A N/A.
CH-004, 005, 006 0
0.75 N/A N/A N/A CH-007 0
2 N/A N/A N/A CH-007 0
0.75 N/A N/A N/A CH-009 0
2 N/A N/A N/A CH-009 0
0.75 N/A N/A N/A ECC-004 Not 0 3
1.22E-05 NO NO ECC-004 Not 0 2
1.01 E-03 NO NO ECC-004 Not 0 0.75 1.82E-03 YES YES NO RC-019 (5001)
Not 0 14 8.43E-06 NO YES
_7 RC-019 (1501)
Not 0 14 8.90E-06 NO YES 19.46%
RC-019 (100)
Not 0 14 9.61 E-06 NO YES RC-019 (5001)
Not 0 12 7.25E-06 YES NO RC-019 (1501)
Not 0 12 7.45E-06 YES NO RC-019 (100)
Not 0 12 7.68E-06 YES NO RC-027, 028, 029 Not 0 2
2.55E-04 YES NO RC-027, 028, 029 Not 0 0.75 3.17E-04 NO YES 2
4.31_
RC-030 0
2 N/A N/A N/A RC-030 0
0.75 N/A N/A N/A RC-031, 032, 033 Not 0 2
3.04E-03 YES NO RC-031, 032, 033 Not 0 0.75 5.64E-03 NO YES 5.52%
RC-055 Not 0 1
2.09E-04 NO YES 3
RC-055 Not 0 0.75 1.44E-04 YES NO RC-057 (1501)
Not 0 4
2.52E-05 NO NO RC-057 (100)
Not 0 4
2.50E-05 NO NO RC-057 (1501)
Not 0 3
4.88E-05 YES YES NO RC-057 (100)
Not 0 3
4.88E-05 YES YES NO RC-058, 059 (1501)
Not 0 3
4.88E-05 YES NO RC-058, 059 (100)
Not 0 3
4.88E-05 YES NO Page 1 of 2 NIMaw Poiliirn Prnjhohilifti IFPP i immorv RC-058,059(1501)__
l NotO V
- 3.
07 E-0 3
- l. I- -.
v RC-058, 059 (1501)
Not 0 j
3.07E-03 NO YES RC-058, 059 (1 00)
I Not 0 1
21 3.07E-03 I
NO I
YES 5121.08%
5103.38%
RC-060B 0
1.5 N/A N/A N/A I
I RC-060B 0
0.75 N/A N/A N/A RC-062 Not 0 0.75 2.52E-04 YES NO RC-062 Not 0 0.5 2.70E-04 NO YES 7.14%
RC-080 Not 0 1
2.1OE-04 NO YES 17.97%
RC-080 Not 0 0.75 1.78E-04 YES NO RC-081 0
1 N/A N/A N/A RC-081 0
0.5 N/A N/A N/A RC-084 Not 0 1
3.46E-05 NO NO RC-084 Not 0 0.75 6.83E-05 YES YES NO Totals:
8 Segments 0 Conditional Consequence 6 Segments Most Limiting FP Used Originally 12 Segments Most Limiting FP Not Used Page 2 of 2 CO2Z RRW SS Comparison between Originial Submittal and Sensivity Study Page 1 of 4 CDF W/O OPERATOR ACTION CDF W/ OPERATOR ACTION LERF W/O OPERATOR ACTION LERF W/ OPERATOR ACTION 4th Interval 4th Interval 4th Interval 4th Interval U ate Sen itivitv Ud ate See itivit S
tivity date Sen rivitv Combined Ranking Expert Panel Segment 4th Interval Selection + Change ID RRW SS RRW SS RRW SS RRW SS RRW SS RRW SS RRW SS RRW SS UpaeSniiiyi ik ACCO001 1.0000 LOW 1.0000 LOW
- 1.
LOW I 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.00001 LOW 1.C000 LOW LOW LOW ACC-002 1.
LOW 1.C000 LOW 1.C000 LOW 1V.0C00 LOW 1.0 LOW 1.3 LOW 1.0000 LOW 1.0000 LOW LOW LOW I_
ACC-0I3 11.0000C LOW 1.0000C LOW 1.0000I LOW 1.0000 LOW 1.00003 LOW 1.0000I LOW 1.0C00CI LOW 1.0000C LOW LOW I
LOW 04 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0001 LOW 1.0000 LOW 1.0001 LOW 1.0001 LOW LOW LOW 05 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0002 LOW 1.0001 LOW 1.0001 LOW 1.0000 LOW LOW LOW 06 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW LOW LOW 07 08 09 I
1.0000 Low 1.0000 Low 1.0000 Low 1.0000 Low 1.0000 Low 1.0000 Low 1.0000 Low 1.0000 Low LOW LOW I
1.0000 Low 1.0000 Low 1.0000 Low 1.0000)
Low 1.0000 Low 1.0000 Low 1.0000 Low 1.0000 Low LOW LOW
!1.0008 LOW 1.0007 LOW 1.0008 LOW 1.0008 LOW 1.0010 LOW 1.0008 LOW 1.0010 LOW 1.0009 LOW LOW LOW I
1.0008 LOW 1.0007 LOW 1.0008 LOW 1.0008 LOW 1.0010 LOW 1.0008 LOW 1.00110 LOW 1.0009 LOW LOW LOW 1.00081 LOW 1.0007 LOW 1.0008 LOW 1.0008 LOW 1.0010 LOW 1.0008 LOW 1.00101 LOW 11.0009 LOW LOW LOW 3 4 1
1 0 M
35 1,00031 LOW 1.0003 LOW 1.0003 LOW 1.0003 LOW 1.0010 Low 1.0009 Low 1.010 MEDIUM 1.0009 Low MDU O
116 1.0003 LOW 1.0003 LOW 1.0003 LOW 1.0003 LOW 1.0010 LOW 1.0009 LOW 100MEIM1.0009 Low MDU LOW 137 1.0003 LOW 1.0003 LOW 1.0003 LOW 1.0003 LOW 1.010 LOW 1.0009 LOW 1.001 MEIM 1.0009 LOW MEDIUM LOW 16
'9 10 Ii 12 13
- 1. 0 7 M EDIUM] 1 0 1 M1.00 3
.003 ME 1.01.
03 MEDIU 1.0035 MEDIUM 1.0032 ME I 1.00M MEDIU
. 0 8 M D U E I M M D U s 1U j C 2
1.0007 MEI 1.0037 EDIU 1.007 M
1.003 MEDU 1.001 U
1.00 MED 1.003MEDM MEDI MEDIUM MEDIMW 4D1.0037 MED 1.0031 MEW 1.0037 MOU 1.0037 MOW 1.00t0 MDU 003032 MLO 1.00 M 1.0039 M W LMEDIUM MEDO I
c03 Page 2 of 4 RRW SS Comparison between Originial Submittal and Sensivity Study CDF W/O OPERATOR ACTION CDF W/ OPERATOR ACTION LERF WIO OPERATOR ACTION LERF W/ OPERATOR ACTION 4th Interval 4th Interval 4th Interval 4th Interval U ate Sen sitivitv U date Sersitivii UU date Sensitivi U ate Ser ity Combined Ranking Expert Panel Segment 4th Interval Selection + Change RRW SS RRW SS RRW SS RRW SS RRW SS RRW SS RRW SS RRW SS Update Sensitivity in Risk RC.004 1M 01 IEUM 7
O E
iU
.0037 MEDIUM 1.
IMEDIUM 1N ME MEDIUM MEDIUM RC 005 7
I 1
MIU 103 MEDIUM 03 MEMI 1.0035 MEDIUM :1.032 0
MEDIUM 1.0036 MEDI MEDIUM MEDIUM RC-006 1.00 MEDIU
.1.07 MEU 100J. MEDIUM 1.004 MEDU 1.04 MEIUM 1.0 MEU MEDIUM 12 EDUM RC-008 15 IUM 1.0 MEDIUI 100W4 MEDI
- 1.
IU 1.
1.03 W
1.I 1.2 EIN MEDIUMI RC-O09 1.0 I
004 ME 1.04 MEU 1.00 M
M 1.0038 MEDI 10044 MEDIUM 1.042 MEDIU MEDIUM MEDIUMi RC-010 lRC.O011____
lRC-012_
IRC-013_
RC-014 RC-015 lRC-016 RC-017 RC..018 I~
1.009 MEDIU W.01 MEDI 1.001l lMEDIUM1.021MlD 1.00a18MEDIUM10017MDU1.0019 MEDIUM 1.02 MEDIU MEDIUM MEGDIU;TlM l1 RC-020 102MEIUM101 EIU:
1.0026 MEDIU 1.02MD
.09MDUM 102 MEIU102 MiEDIUM102 EiU EIUMMDU RC 1.0010 LOW 1.0007 LOW 1.0010 LOW 1.009 LOW 1.0009 LOW 1.0008 LOW 1.0009 LOW 1.0009 LOW LOW Low RC022 1.0010 LOW 1.0007 LOW 1.0010 LOW 1.0009 LOW 1.0009 LOW 1.0008 LOW 1.0009 LOW 1.0009 LOW LOW LOW RC23 1.0010 LOW I1.0007 LOW 1.0010 LOW 1.0009 LOW 1.0009 LOW 1.0008L LOW 1.0009 LOW LOW LOW RC-024 1.0012 MEDIUM 1.0009 LOW 1
M MEU 1014' I
4 MED RC O25 1.0012 MEDIUM 1.0009 LOW 1.00 IM11 1I11 MEI 1
M RC-26 1.0012 MEDIUMI 1.0009 LOW MEUMI DMI II C 0 1.;00012 MEDIU 1.0012 I
1.0012 MIUM 1.0014 I LOW 1.0014 MIUMOWI 1.0015 I
1.0014 MEIUW M 1.0017 MI ME 1.2 U1-.2 M
1.0M00 1.0012 M M 1OW14 IMEDUL10I 14 MI 1.001 E
014 MU 1001 EI MEDIUM MEDIUM C-6 1.001 MEDIUM 1.0012 EIO I 1.0012 MIUMI 1.0013 MEI OWI 1.0014 MEDwIU 1.0015 DIL 1.004 MDIUoM 1.001 ME3I MEDIUM MDU RC-030 I
-I_
RC-035 1.0000 LW 100 LO 1.00LW 100 LO 1.00LW 100 LW 1000LOW 1.0000 LOW LOW LOW RC-036 1.0000 LO
_.00 LO 1._0 LO 1.000 LOWl 1.0000 LOW 100 LOW 1.00 LOW 1.00lO LOW LO RC-037 RC-038 IRC-039 RC-040 1
M016 MEDI MEDUM 1.0018 l0MEDIUii MEDIUM RC-041 RC-042 RRW SS Comparison between Originial Submittal and Sensivity Study Page 3 of 4 4a"
'044 w045
-i
_ 1
,,.vlv..
I O
I LUW I
I LOW I
_-LOWT
_ 1.
U.
-I1 i
U I 1.000 I
LOW I.07 1 I1 1.00081 LOW 1.0008 I
tf CO5 Page 4 of 4 RRW SS Comparison between Originial Submittal and Sensivity Study CDF W/O OPERATOR ACTION CDF W/ OPERATOR ACTION LERF W/O OPERATOR ACTION LERF W/ OPERATOR ACTION 4th Interval 4th Interval 4th Interval 4th Interval U
Sdate Sensitivti Update Sensitivity Update Seitiv Upda Sertv Combined Ranking Expert Panel Segment 4th Interval Selection + Change ID RRW SS RRW SS RRW SS RRW SS RRW SS RRW SS RRW SS RRW SS Update Sensitivity in Risk RC-081 RC-082 1.0007 LOW 1.0005 LOW 1.0007 LOW 1.0006 LOW 1.0008 LOW 1.0007 LOW 1.0008 LOW 1.0007 LOW LOW LOW RC4083 RC-084 1.0006 LOW 1.0005 LOW 1.0006 LOW 1.0006 LOW 1.0008 LOW 1.0007 LOW 1.0008 LOW 1.0007 LOW LOW LOW RC45 RC-087 RC4O88 RC-M8 RC-09 RC-091
=
RC-092
==
=
=
=
==
=
=
=-
RC.093 1.0004 LOW 1.0003 LOW 1.0004 LOW 1.0004 LOW 1.0005 LOW 1.0004 LOW 1.0005 LOW 1.0005 LOW LOW Low RC-094 1.0004 LOW 1.0003 LOW 1.0004 LOW 1.0004 LOW 1.0005 LOW 1.0004 LOW 1.0005 LOW 1.0005 LOW LOW LOW RC095 1.0004 LOW 1.0003 LOW 1.0004 LOW 1.0004 LOW 1.0005 LOW 1.0004 LOW 1.0005 LOW 1.0005 LOW LOW LOW RC-096 1.014 MEDIUM 1.000 MEIUD 1.0 MEDI 1.0016 ME 1.01 M I 1.17 ME M 1.0015 Wm MEDIU MEDIUM RC-097 RC498 RC-099
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RC-100 RH-001 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0004 LOW 1.0003 LOW 1.0004 LOW 1.0004 LOW LOW LOW RH-002 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW LOW LOW RH-003 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW 1.0000 LOW LOW LOW Segments with re-calculated failure probability The blanks represent no consequence ACC-Safety Injection (SI) Accumulator System Segments CH-Chemical and Volume Control System Segments ECC-Si Emergency Core Cooling System Segments RC-Reactor Coolant System Segments RH-Residual Heat Removal System Segments 4th Interval Update:
Results from the revised fourth interval RI-ISI Program Sensitivity:
Results from the sensitivity study with the re-calculated failure probabilities for the 12 multi-line segments Combined Ranking: Overall ranking of the segment based on the RRW values from CDF w/o Operator Action, CDF w/ Operator Action, LERF w/o Operator Action, LERF w/ Operator Action RRW:
Risk Reduction Worth SS:
Safety Significant Class CDF:
Core Damage Frequency LERF: