ML063170266
| ML063170266 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 06/15/2006 |
| From: | NRC/RES/DRASP/DDOERA/OEGI |
| To: | |
| Shared Package | |
| ML063170246 | List: |
| References | |
| ir-04-005 | |
| Download: ML063170266 (54) | |
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Final Precursor Analysis Accident Sequence Precursor Program -- Office of Nuclear Regulatory Research Watts Bar Unit 1 Silt Accumulation in ERCW System Event Date 11/22/2004 LER IR 05000390/2004005 CDP 7.5 x 10-6 June 15, 2006 Event Summary Description On November 22, 2004, while performing a manual valve exercising procedure it was determined that the backup cooling line from the Essential Raw Cooling Water (ERCW) system to the lube oil cooler for the 1A-A Centrifugal Charging Pump (CCP) was completely blocked with silt. This line provides backup cooling to this CCP in the event of loss of the normal cooling from the Component Cooling System (CCS). This pump is the only high head pump provided with backup cooling. The blocked line was mechanically cleared with the unit remaining on line at 100% power during the process.
This condition placed the unit in a situation where, if the CCS is lost, all Reactor Coolant Pump (RCP) seal cooling and high pressure injection is lost. This results in a seal LOCA and core damage.
Cause The unavailability of the ERCW backup cooling for the 1A-A CCP was due to the accumulation of silt and/or debris in this standby, not normally flowing, line. This was the latest in a series of observations of significant buildup of silt/debris in the ERCW lines beginning in early 2004. The inspection report (Reference 1) does not include a root cause for this increased occurrence of silt buildup.
Condition Duration In early 2004, Watts Bar began to observe significant buildup of silt in the ERCW lines.
Between 2/19/2004 and 10/4/2004 ten Problem Evaluation Reports (PERs) were prepared concerning silt/debris blockage of ERCW lines. None affected component operability since they involved only partial blockage or the blockage cleared when flow was initiated. The earliest recent report concerning blockage specifically attributed to silt/debris was a PER on 7/29/2003 involving a small (5-10%) buildup in the ERCW B train backup supply to the Turbine Driven Auxiliary Feed Water (TDAFW) pump. The condition duration is assumed to be 6024 hours0.0697 days <br />1.673 hours <br />0.00996 weeks <br />0.00229 months <br /> (251 days) which is half of the time from the prior successful testing of the ERCW line to the 1A-A CCP until it was found plugged.
Other Related Conditions or Events During the Condition Period A review of LERs and Inspection Reports from the beginning of 2004 until the present did not identify any Engineered Safety Feature operability issues.
Reference 1 identifies PERs in the time period from early 2004 until the complete blockage of the ERCW line to the 1A-A CCP associated with silt/debris blockage to the following components:
1.
ERCW supply to A, B and C Station Air Compressors 2.
ERCW A train backup supply to Turbine Driven Auxiliary Feed Water (TDAFW) pump (2 reports) 3.
ERCW backup supply to the Train A CCS surge tank (2 reports) 4.
ERCW backup supply to the Train B CCS surge tank (2 reports) 5.
ERCW flood mode return line 6.
ERCW B train backup supply to TDAFW pump 7.
ERCW supply to the 1A containment spray heat exchanger In each case component operability was not in question since each occurrence involved only partial blockage or the blockage cleared when flow was initiated. The number of events, and in particular the repeated events, indicates that the probability of inoperability due to blockage might be higher than the nominal values.
Analysis Results Importance The point estimate importance of the described condition for the 6024 hour0.0697 days <br />1.673 hours <br />0.00996 weeks <br />0.00229 months <br /> duration is CDP = CCDP - CDP = (8.8 x 10-5) - (8.0 x 10-5) = 7.5 x 10-6 The GEM report for this assessment is provided in Appendix C.
The uncertainty distribution is compared to the point estimate for the conditional core damage probability and the revised base case core damage probability as follows.
5%
Mean Point Estimate 95%
CDP 7.9E-06 7.0E-05 8.0E-05 2.4E-04 CCDP 1.0E-05 1.5E-04 8.8E-05 5.7E-04 CDP 7.5E-06
Dominant Sequences The dominant accident sequences which collectively contribute to more than 98% of the CDP are listed in Table 1 and are shown graphically in Figures A-1 through A-4 of Appendix A. All other sequences individually contribute less than 0.6% of the total.
The three dominant sequences are initiated by a total loss of Component Cooling Water, which with failure of the ERCW to the 1A-A Centrifugal Charging Pump due to the debris, leads to loss of RCP seal cooling, seal failure with no high pressure injection available and core damage. In sequence 3-02-06, the RCP stage 2 fails due to binding or popping. In sequence 3-03-06 the RCP stage 1 fails due to binding or popping. In sequence 3-04-3, both seal stages fail.
Results Tables The conditional probabilities for the dominant sequences are shown in Table 1.
The event tree sequence logic for the dominant sequences are presented in Table 2a.
Table 2b defines the nomenclature used in Table 2a.
The most important cut sets for the dominant sequences are listed in Table 3.
Definitions and probabilities for modified or dominant basic events are provided in Table 4.
Total Loss of Component Cooling Water Initiating Event The frequency of the total loss of component cooling water initiating event is an important contributor to the importance of the described condition. This frequency and its uncertainty distribution is Frequency (per year)
Point Estimate Mean 5%
Median 95%
IE-LOCCW 1.04E-04 1.06E-04 1.85E-05 6.36E-05 3.25E-04 The important cut sets that contribute to the loss of CCW (CCS at Watts Bar) initiating event frequency are apparent in the dominant sequence cutsets in Table 3. Common cause plugging and fouling of the heat exchangers and of the CCW pumps seem to be the major causes of the initiator. A flow diagram of the Watts Bar CCW system is provided in Appendix E.
Modeling Assumptions Analysis Type This event is analyzed as a condition event assessment involving the unavailability of the backup ERCW supply to the 1A-A CCP. The initial evaluation was performed using the Condition Assessment feature of GEM 7.25 software package with event tree and fault tree modifications made using the SAPHIRE 7.25 software package. The final analysis was performed with SAPHIRE/GEM 7.26. The WBNP model utilized was a further modification to a revision by INEL of the Revision 3.11 WBNP SPAR model to include a complete loss of CCS (LOCCW) initiating event (Reference 3). This revision was prepared by INEL in order to perform the SDP Phase III analysis reported in Reference 2.
Unique Design Features Only one high pressure injection source, CCP 1A-A, is available upon loss of the CCS and this availability depends on the ERCW system.
WBNP was originally designed as a two unit plant. The CCS was to be shared between units. Although Unit 2 was not completed, the common portions of the CCS were completed consequently the Unit 1 CCS benefits from some added redundancy in CCS pumps.
Modeling Assumptions Summary Key modeling assumptions. The key modeling assumptions are listed below and discussed in detail in the following sections. These assumptions are important contributors to the overall risk. Since the revised model which was the starting point for this analysis has not been released by INEL, the major changes in the INEL model as well as the current modifications made to analyze this condition are described below.
S Loss of Component Cooling System Initiating Event The unavailability of the ERCW backup supply to the 1A-A CCP is most important for a complete loss of the CCS. This backup is utilized if Train A of the CCS is unavailable. If Train B of the CCS is also unavailable, either as a result of an initiating event or during the mission time of another initiating event, then all high head injection pumps are lost.
This results in loss of seal cooling and the potential for a seal LOCA which then leads to core damage.
The Revision 3.11 SPAR model for WBNP includes a loss of Train A of the CCS (LOCCW-A) initiating event but does not include the loss of both trains as an initiating event. An event tree for the total loss of CCS (LOCCW) has been added by INEL for the Phase III SDP assessment. The event tree is identical to the LOCCW-A event tree.
The initiating event frequency is obtained from a fault tree model that assumes that the
failure of the running pump in Train A is followed within a 3 day time period by failure of the other Train A pump and Train B failure. The only common cause failures in the LOCCW initiating event frequency assessment are failure of four of four CCS pumps to run and failure of two of two standby CCS pumps to start. No recovery of any of the failed running CCS pumps is considered in the model.
Common cause failure of both of the CCS heat exchangers (one in each train) is not modeled in the INEL LOCCW initiating event model but is included in the models for loss of CCS following the other initiating events. SPAR database values for heat exchanger failures indicates that these failures could be important contributors to loss of CCS events.
Information on heat exchanger failure rates (Reference 4) implies two failure modes or causes, fouling and plugging, both with rates significantly less than that given in the SPAR database. It is assumed that fouling is a degradation of the ability of the surfaces to transfer heat and occurs more gradually over a period of time which is measured in days. Plugging is assumed to be a blockage of the flow through the heat exchanger and could occur over a very short time span.
Fouling and plugging of the heat exchangers were therefore added to all of the Watts Bar SPAR models associated with loss of CCS. It was assumed that the approach to fouling failure could be detected by the normal monitoring of CCS temperatures and the spare CCS heat exchanger (normally being used for fuel pool cooling) valved into service. Plugging, on the other hand, is assumed to be sufficiently rapid that the spare heat exchanger cannot be used. Since the spare heat exchanger is in normal use and therefore subject to the same conditions as the CCS Train A and B heat exchangers, all the CCS heat exchangers are included in the same common cause group for failure due to fouling.
Plugging of ERCW line to 1A-A CCP Plugging of the relatively large normally flowing portions of the ERCW side of the CCS heat exchangers would be expected to require a significant amount of material. Given this, it is considered highly likely that the relatively small, not normally flowing ERCW line to the 1A-A CCP oil cooler would be plugged when ever there is a complete loss of CCS due to common cause plugging of the CCS heat exchangers. This assumption is incorporated in the base case model.
Condition Duration The condition duration is assumed to be 6024 hours0.0697 days <br />1.673 hours <br />0.00996 weeks <br />0.00229 months <br /> (251 days) which is half of the time from the prior successful testing of the ERCW line to the 1A-A CCP until it was found plugged.
Reference 1 notes that this line was found blocked in April 1999 but the cause was not known. Subsequently, 4 successful flushes were performed with the last being in July
2003 (about July 10 - Reference 2) or approximately 17 months (501 days) prior to the discovery of the blocked line on 10/22/2004. The required frequency of silt accumulation tests on this line was once every 18 months.
Since the exact time the blockage occurred is unknown, half of the actual last test interval will be used as the duration or 251 days. This corresponds to approximately the middle of March 2004 which is after the first report of significant blockage in other ERCW lines. The date of previous tests of any other ERCW line without blockage is not known and it is therefore possible that the ERCW line to the 1A-A CCP could have been blocked for one year or more. A duration of one year will be evaluated in a sensitivity analysis.
Plugging of Other ERCW Lines As discussed above, in the nine months prior to the discovery of the blocked ERCW line, debris and or silt accumulation was found in seven other ERCW lines. However, no instances of loss of function were found. All but one of these lines were standby lines with no flow under normal conditions. The single instance of silt/debris accumulation in a line with flow during normal conditions is that for the three station air compressors aftercoolers. The related PER does not indicate that performance was degraded. The lines to the aftercoolers are much smaller than those for the CCS heat exchangers and therefore the lines to the aftercoolers are considered to be more prone to silt accumulation than the lines to the CCS heat exchangers.
All but one of the standby lines found with the silt debris accumulation are utilized only for seismic or external flooding initiating events. In these instances the normal function is degraded by the initiating event and reliance is made on the ERCW system.
Complete blockage and unavailability of these lines would therefore not impact the risk for internal initiating events.
The single instance of partial silt/debris blockage in a ERCW standby line to safety system required after a design basis accident was the line to the 1A containment spray heat exchanger. While the accumulation was not cleared by flow through the small drain line, it would have been cleared by the very much higher flow through the heat exchanger if it would have been initiated. Further, containment spray heat removal is not needed after an accident and it is not included in the SPAR Watts Bar model.
Based on the above assessments, it is assumed that the only ERCW line unavailable is the line to the 1A-A CCP and the nominal frequency of fouling and plugging are applicable to the conditions found.
Recovery Opportunities Diagnosing the cause of the failure of backup cooling to the 1A-A CCP and clearing the blockage is not considered an option under the circumstances associated with the demand for this cooling which is a complete loss of CCS.
The failure of the ERCW backup cooling to the 1A-A CCP is only important for failure of the CCS Train A as part of an initiating event or during the mission time following another initiator. Recovery of the CCS is therefore a possible recovery opportunity that would prevent core damage.
Other assumptions. Other assumptions that have a negligible impact on the results due to relatively low importance include the following:
The spare CCS heat exchanger is assumed to be available only if the Train A heat exchanger is found to be subject to a fouling failure. While the spare heat exchanger would also be available if the Train B heat exchanger were found to be subject to fouling, the Train B heat exchanger is less important and this option is not included in the model.
Event Tree Modifications An event tree for the total loss of the CCS was added for the Phase III SDP analysis and, except for the initiating event, is identical to the event tree for the partial loss of CCS (LOCCW-A). These two trees were modified for this analysis by adding a new initiating event in front of the existing initiating event. The new initiating events (IE-D-LOCCW and IE-D-LOCCW-A) have values of 1.0 and are inserted to enable SAPHIRE/GEM to treat the loss of CCS initiating events (IE-LOCCW and IE-LOCCW-A) as any other top event in the event tree. Sequence cut sets therefore include the basic events that cause the initiating event. (See Figures A-1 and A-2)
Fault Tree Modifications LOCCW Initiating Event - A new fault tree (IE-LOCCW) for determining the frequency of the total loss of the CCS was created for the Phase III SDP (References 2 and 3).
This fault tree required failure of CCS Train A (IE-LOCCW-A) and CCS Train B (IE-LOCCW-B) and effectively included only failure of the CCS pumps. These fault trees (IE-LOCCW-A and IE-LOCCW-B) were revised for this analysis to include both fouling and plugging failure of the heat exchangers. Loss of CCS Train A occurs due to fouling if its normally in use heat exchanger (HTX A) fouls and either, the spare heat exchanger (HTX B) fouls or is not utilized. Loss of CCS Train B occurs if the Train B heat exchanger (HTX C) fouls. For either train, failure occurs if the trains heat exchanger plugs either as an independent event or as a common cause event. The revised fault trees are shown in Figures A-5, A-6 and A-7.
Common cause failure of the heat exchangers due to fouling is modeled by adding new recovery rules for the LOCCW sequences as shown in Table A-1. If independent failure of all 3 heat exchangers occur in a cut set then a new cut set is created which includes the common cause failure of 3 in a group of 3 given that one has failed. Similarly, if only 2 fouling failures appear in a cut set (which occurs when the spare heat exchanger is
not utilized) a new cut set is created which includes the common cause failure of 2 in a group of 2 given that one has failed.
The above method of incorporating CCFs using recovery rules can be very sensitive to truncation value selected for solving the sequences. If the truncation value is too high, cut sets involving the independent failures will not be included in the solution prior to applying the recovery rules. A truncation value of 1E-16 was selected based on consideration of the independent failure cut sets expected. The adequacy of this was demonstrated by a sensitivity study that shows convergence when the truncation limit is lowered by an order of magnitude.
LOCCW-A Initiating Event - The frequency of the loss of CCS Train A is obtained from the IE-LOCCW-A fault tree described above. The recovery rules for sequences from this initiator are however different in that they involve only common cause failure of the Train A components and are shown in Table A-1.
CCW-A, CCW-B, and CCW-A-RECIRC - These fault trees which model the CCS support function to mitigating systems after other initiating events were revised in a similar fashion as the initiating event fault trees described above (See Figures A-8, A-9 and A-10).
CVC-MDPA and CVC-MDPS-SEAL - In these fault trees which model the failure of the charging pumps were revised to add failure of the ERCW backup cooling to CCP-1AA whenever both CCS heat exchangers fail due to common cause plugging. (See Figures A-11 and A-12).
Basic Event Probability Changes Table 4 provides all the basic events that were added or revised in the fault tree models described above, were modified to reflect the best estimate of the conditions during the event, or are in the important cut sets in the dominant sequences. The basis for these changes are provided below:
Heat Exchanger Plugging - The probability of heat exchanger plugging was taken to be 3E-08 per hour (Reference 4) with the mission time being either 8760 hours0.101 days <br />2.433 hours <br />0.0145 weeks <br />0.00333 months <br /> for an initiating event, 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> as the time associated with the LCO of a heat exchanger being out of service or 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for the mission time following another initiating event.
Heat Exchanger Fouling - The probability of heat exchanger fouling was taken to be 1E-07 per hour (Reference 4) with the mission time being as described above.
Common Cause Failure Rates - The common cause failures due to plugging or fouling were utilized the SPAR template alpha factor values for plugging.
Spare Heat Exchanger Not Utilized - These human errors were obtained from application of the SPAR-H methodology (Reference 5). The work sheets are provided in Appendix B.
Sensitivity Analyses Sensitivity analyses were performed to determine the effects of model uncertainties on results based on best estimate assumptions. The following table provides the results of the sensitivity analyses.
Case Parameter Modification Results 1
Heat Exchanger Plugging Increase by factor of 25 to original template rate CCDP = 6.2 x 10-4, CDP = 8.0 x 10-5, CDP = 5.4 x 10-4 2
Case 1 and reduced Common Cause Plugging Failure Case 1 and reduce Alpha 2 to 0.01 and Alpha 3 to 0.005 CCDP = 1.1 x 10-4, CDP = 8.0 x 10-5, CDP = 3.3 x 10-5 3
No heat exchanger plugging failures in LOCCW initiating events Set all plugging failures in initiating event model to zero CCDP = 8.1 x 10-5, CDP = 8.0 x 10-5, CDP = 1.0 x 10-6 4
Truncation in GEM Analysis Reduce GEM analysis truncation from 1E-16 to 1E-17 CCDP = 8.8 x 10-5, CDP = 8.0 x 10-5, CDP = 7.6 x 10-6 The first sensitivity case utilizes the original SPAR template heat exchanger plugging rate (2.5E-06/hour) in the above described revised model. With the high plugging CCF (Alpha 2 of 0.169), this increases the LOCCW frequency to 3.7E-03 per year and the frequency of plugging of a single CCW heat exchanger as 2.2E-02 per year.
The second sensitivity case utilizes the higher plugging failure rate but recognizes that if the plugging is gradual then the likelihood of a second heat exchanger plugging during the time it takes to clear the plugged heat exchanger is relatively small (see Reference 6) or that there is a good chance that the situation will be noticed prior to failure and steps taken to avoid the total loss of CCW. The resulting LOCCW frequency is 2.6E-04 per year.
The third sensitivity study eliminates heat exchanger plugging as a cause of a loss of CCW initiating event. The resulting LOCCW frequency is 6.1E-05 per year.
The fourth sensitivity study was run to confirm that the truncation used was sufficiently low. As noted above, the manner of introducing the CCF in the initiating event model requires that the truncation used to determine the cut sets
IR 05000390/2004005 10 prior to the application of the recovery rules be sufficiently low to capture all important independent failures. The overall result of the sensitivity study is essentially the same as the condition analysis base case. The difference in the second digit of the importance exaggerates the true difference due to rounding off to two significant digits. The CCDP and importance of the individual sequences are also the same (except for similar rounding changes in the second digit) for the top six sequences with differences appearing in some subsequent sequences with CCDPs less than 4E-08. It should be noted that in the sensitivity study the CDP values were based on a 1E-16 truncation. If the CDP values had been redone using a 1E-17 truncation the CDP values would have increased resulting in a slight reduction in importance.
These results show the sensitivity of the importance of condition found at Watts Bar is strongly dependent on the assumptions concerning heat exchanger failures.
References 1.
Watts Bar NRC Integrated Inspection Report 05000390/200405 and 05000391/200405, January 28, 2005.
2.
NRC Integrated Inspection Report No. 05000390/2005007; Preliminary White Finding; Watts Bar Nuclear Power Plant, March 2, 2005.
3.
WBAR_312_FTIE, obtained from Robert F. Buell, INEL, June 20, 2005.
4.
Steven A. Eide, INL, E-mail to Bruce Mrowca, ISL, July 19, 2005 (See Appendix D).
5.
David Getman, et. Al., The SPAR-H Human Reliability Analysis Method, NUREG/CR-XXXX, October 2003.
6.
Thomas E. Wierman, INL, E-Mail to John A Schroeder, INL, July 28, 2005 (See Appendix D).
IR 05000390/2004005 11 Table 1. Conditional core damage probabilities of dominating sequences.
Event tree name Sequence no.
CCDP1 Contribution CDP1 Contribution LOCCW 3-02-06 1.4E-5 16%
6.9E-6 92%
LOCCW 3-03-06 7.2E-7 1%
3.8E-7 5%
LOCCW 3-04-3 1.8E-7
<1%
9.4E-8 1%
Total (all sequences)2 8.8E-5 100%
7.5E-6 100%
- 1. Values are point estimates.
Table 2a. Event tree sequence logic for dominating sequences.
Event tree name Sequence no.
Logic
(/ denotes success; see Table 2b for top event names)
LOCCW 3-02-06 IE-LOCCW /RPS /AFW LOSC /RCPT /RSD /BP1 BP2 HPI LOCCW 3-03-06 IE-LOCCW /RPS /AFW LOSC /RCPT /RSD BP1 /BP2 HPI LOCCW 3-04-3 IE-LOCCW /RPS /AFW LOSC /RCPT /RSD BP1 BP2 /ACC-M HPI-M Table 2b. Definitions of top events listed in Table 2a.
Top Event Definition ACC-M ACCUMULATOR 2-OF-3 AFW AUXILIARY FEEDWATER BP1 RCP SEAL STAGE 1 INTEGRITY (BINDING/POPPING)
BP2 RCP SEAL STAGE 2 INTEGRITY (BINDING/POPPING)
HPI HIGH PRESSURE INJECTION HPI-M HIGH PRESSURE INJECTION 2/4 TRAINS IE-LOCCW TOTAL LOSS OF COMPONENT COOLING LOSC LOSS OF ALL SEAL COOLING RCPT REACTOR COOLANT PUMPS TRIPPED RPS REACTOR PROTECTION SYSTEM RSD RAPID SECONDARY DEPRESSURIZATION (<1710 PSI IN 2 HR)
IR 05000390/2004005 12 Table 3. Conditional cut sets for the dominant sequences.
CCDP Percent Contribution Minimum Cut Sets (of basic events)
Event Tree: LOCCW Sequence 3-02-06 6.03E-06 42.6 IE->IE-D-LOCCW, IE-CCW-CF-HXPL-AANDC, /RCS-MDP-LK-BP1, RCS-MDP-LK-BP2 3.40E-06 24.0 IE->IE-D-LOCCW, CCW-HTX-CF-FOUL3-3, IE-CCW-HTX-FOUL-HXA, /RCS-MDP-LK-BP1, RCS-MDP-LK-BP2 2.30E-06 16.2 IE->IE-D-LOCCW, CCW-MDP-CF-RUN4-4, CCW-XHE-XL-1BB, FLAG-CCW-1B-RUNNING, IE-CCW-MDP-FR-1BB,
/RCS-MDP-LK-BP1, RCS-MDP-LK-BP 2.30E-06 16.2 IE->IE-D-LOCCW, CCW-MDP-CF-RUN4-4, CCW-XHE-XL-1AA, FLAG-CCW-1A-RUNNING, IE-CCW-MDP-FR-1AA,
/RCS-MDP-LK-BP1, RCS-MDP-LK-BP2 1.42E-05 100 Total (all cut sets)1 CCDP Percent Contribution Minimum Cut Sets (of basic events)
Event Tree: LOCCW Sequence 3-03-06 3.05E-07 42.6 IE->IE-D-LOCCW, IE-CCW-CF-HXPL-AANDC, RCS-MDP-LK-BP1,
/RCS-MDP-LK-BP2 1.72E-07 24.0 IE->IE-D-LOCCW, CCW-HTX-CF-FOUL3-3, IE-CCW-HTX-FOUL-HXA, RCS-MDP-LK-BP1, /RCS-MDP-LK-BP2 1.16E-07 16.2 IE->IE-D-LOCCW, CCW-MDP-CF-RUN4-4, CCW-XHE-XL-1AA, FLAG-CCW-1A-RUNNING, IE-CCW-MDP-FR-1AA, RCS-MDP-LK-BP1, /RCS-MDP-LK-BP2 1.16E-07 16.2 IE->IE-D-LOCCW, CCW-MDP-CF-RUN4-4, CCW-XHE-XL-1BB, FLAG-CCW-1B-RUNNING, IE-CCW-MDP-FR-1BB, RCS-MDP-LK-BP1, /RCS-MDP-LK-BP2 7.17E-07 100 Total (all cut sets)1
IR 05000390/2004005 13 CCDP Percent Contribution Minimum Cut Sets (of basic events)
Event Tree: LOCCW Sequence 3-04-3 7.63E-08 42.6 IE->IE-D-LOCCW, IE-CCW-CF-HXPL-AANDC, RCS-MDP-LK-BP1, RCS-MDP-LK-BP2 4.31E-08 24.0 IE->IE-D-LOCCW, CCW-HTX-CF-FOUL3-3, IE-CCW-HTX-FOUL-HXA, RCS-MDP-LK-BP1, RCS-MDP-LK-BP2 2.91E-08 16.2 IE->IE-D-LOCCW, CCW-MDP-CF-RUN4-4, CCW-XHE-XL-1AA, FLAG-CCW-1A-RUNNING, IE-CCW-MDP-FR-1AA, RCS-MDP-LK-BP1, RCS-MDP-LK-BP2 2.91E-08 16.2 IE->IE-D-LOCCW, CCW-MDP-CF-RUN4-4, CCW-XHE-XL-1BB, FLAG-CCW-1B-RUNNING, IE-CCW-MDP-FR-1BB, RCS-MDP-LK-BP1, RCS-MDP-LK-BP2 1.79E-07 100 Total (all cut sets)1
- 1. Total Importance includes all cut sets (including those not shown in this table).
IR 05000390/2004005 14 Table 4. Definitions and probabilities for modified and dominant basic events.
Name Description Calc. Prob.
Lam CCW-HTX-CF-FOUL2-2 CCF DUE TO FOULING OF 2 OF 2 CCW HTXS GIVEN 1 HAS FOULED 1.69E-01 CCW-HTX-CF-FOUL3-3 CCF DUE TO FOULING OF 3 OF 3 CCW HTX GIVEN 1 HAS FOULED 2.86E-02 CCW-HTX-CF-HXAC CCF OF CCW HEAT EXCHANGERS HX-A & C 1.22E-07 CCW-HTX-FOUL-HXA CCW HEATEXCHANGER HTXA FOULS DURING MISSION 2.40E-06 CCW-HTX-FOUL-HXB CCW HEAT EXCHANGER HTXB FOULS DURING MISSION 2.40E-06 CCW-HTX-FOUL-HXC CCW HEAT EXCHANGER HTX C FOULS DURING MISSION 2.40E-06 CCW-HTX-PG-HXA CCW HEAT EXCHANGER HXA PLUGS 7.20E-07 CCW-HTX-PG-HXC CCW HEAT EXCHANGER HXC PLUGS 7.20E-07 CCW-HTX-PG-HXC-LCO CCW HEAT EXCHANGER HX C PLUGS DURING LCO 2.16E-06 CCW-MDP-CF-RUN4-4 CCF OF 4-OF-4 CCW PUMPS TO RUN GIVEN 1 FAILED 9.67E-04 CCW-XHE-XL-1AA OPERATOR FAILS TO RECOVER CCW PUMP 1A-A 1.00E+00 CCW-XHE-XL-1BB OPERATOR FAILS TO RECOVER CCW PUMP 1B-B 1.00E+00 CCW-XHE-XM-HXB CCW HEAT EXCHANGER B NOT UTILIZED 3.25E-02 CVS-XHE-XM-CPP1AA OPERATOR FAILS TO ALIGN ERCW TO CPP-1AA UPON LOSS OF CCW 1.50E-01 (TRUE) 1 FLAG-CCW-1A-RUNNING CCW PUMP 1A-A IS RUNNING 5.00E-01 FLAG-CCW-1B-RUNNING CCW PUMP 1B-B IS RUNNING 5.00E-01 IE-CCW-CF-HXPL-AANDC CCF OF CCW HEAT EXCHANGERS A AND C PLUG 4.44E-05 IE-CCW-HTX-FOUL-HXA CCW HEAT EXCHANGER A FOULS 8.76E-04 IE-CCW-HTX-FOUL-HXB CCW HEAT EXCHANGER HX B FOULS 7.20E-06 IE-CCW-HTX-FOUL-HXC CCW HEAT EXCHANGER HX C FOULS 7.20E-06 IE-CCW-HTX-PG-HXA CCW HEAT EXCHANGER HX A PLUGS 2.63E-04 IE-CCW-MDP-FR-1AA CCW PUMP 1A-A FAILS TO RUN (INITIATING EVENT) 3.50E-02 IE-CCW-MDP-FR-1BB CCW PUMP 1B-B FAILS TO RUN (INITIATING EVENT) 3.50E-02 IE-CCW-XHE-XM-HXB CCW HEAT EXCHANGER NOT UTILIZED (INITIATING EVENT) 6.50E-03 IE-D-LOCCW TOTAL LOSS OF CCW DUMMY = 1.0 1.00E+00 IE-D-LOCCW-A PARTIAL LOSS OF CCW (DUMMY = 1.0) 1.00E+00 RCS-MDP-LK-BP1 RCP SEAL STAGE 1 INTEGRITY (BINDING/POPPING OPEN) FAILS 1.25E-02 RCS-MDP-LK-BP2 RCP SEAL STAGE 2 INTEGRITY (BINDING/POPPING OPEN) FAILS 2.00E-01
- 1. Set to TRUE for the condition assessment
IR 05000390/2004005 IR 05000390/2004005 Appendix A Event Tree and Fault Tree Figures and Recovery Tables
IR 05000390/2004005 16 HPR HIGH PRESSURE RECIRC FAB FEED AND BLEED LOSC RCP SEAL COOLING MAINTAINED MFW MAIN FEEDWATER AFW AUXILIARY FEEDWATER RPS REACTOR PROTECTION SYSTEM IE-LOCCW TOTAL LOSS OF COMPONENT COOLING IE-D-LOCCW TOTAL LOSS OF CCW DUMMY =
1.0 END-STATE FREQUENCY 1
OK 2
OK 3
T LOSC 4
OK 5
T LOSC 6
OK 7
CD 8
CD 9
CD LOCCW - WATTS BAR 1 & 2 PWR B LOSS OF COMPONENT COOLING W ATER 2005/10/10 Figure A-1. LOCCW - Watts Bar 1 and 2 PWR B Loss of Component Cooling Water
IR 05000390/2004005 17 HPR HIGH PRESSURE RECIRC FAB FEED AND BLEED LOSC RCP SEAL COOLING MAINTAINED MFW MAIN FEEDWATER AFW AUXILIARY FEEDWATER RPS REACTOR PROTECTION SYSTEM IE-LOCCW-A PARTIAL LOSS OF COMPONENT COOLING IE-D-LOCCW-A PARTIAL LOSS OF CCW (DUMMY = 1.0)
END-STATE FREQUENCY 1
OK 2
OK 3
T LOSC 4
OK 5
T LOSC 6
OK 7
CD 8
CD 9
CD LOCCW -A - WATTS BAR 1 & 2 PW R B LOSS OF COMPONENT COOLING WATER TRAIN 2006/05/03 Figure A-2. LOCCW-A - Watts Bar 1 and 2 PWR B Loss of Component Cooling Water Train
IR 05000390/2004005 18 O2 RCP SEAL STAGE 2 INTEGRITY (O-RING EXTRUSION)
BP2 RCP SEAL STAGE 2 INTEGRITY (BINDING/POPPING)
O1 RCP SEAL STAGE 1 INTEGRITY (O-RING EXTRUSION)
BP1 RCP SEAL STAGE 1 INTEGRITY (BINDING/POPPING)
RSD RAPID SECONDARY DEPRESSURIZATION
RCPT REACTOR COOLANT PUMPS TRIPPED LOSC LOSS OF ALL SEAL COOLING END-STATE NOTES 1 OK 21-GPM/RCP 2
T SLOCA 182-GPM/RCP 3
T SLOCA 76-GPM/RCP 4
T MLOCA 480-GPM/RCP 5 OK 21-GPM/RCP 6
T SLOCA 172-GPM/RCP 7
T SLOCA 182-GPM/RCP 8
T SLOCA 61-GPM/RCP 9
T SLOCA 300-GPM/RCP 10 T
SLOCA 300-GPM/RCP 11 T
SLOCA 76-GPM/RCP 12 T
SLOCA 300-GPM/RCP 13 T
MLOCA 480-GPM/RCP 14 T
MLOCA 480-GPM/RCP 0.0125 0.0125 0.500 0.200 0.200 0.200 0.200 0.200 0.500 0.500 0.500 LOSC - WATTS BAR 1 & 2 PWR B LOSS OF SEAL COOLING 2005/01/31 Figure A-3. LOSC - Watts Bar 1 and 2 PWR B Loss of Seal Cooling
IR 05000390/2004005 19 HPR HIGH PRESSURE RECIRC RHR RESIDUAL HEAT REMOVAL PZR RCS DEPRESS FOR RHR SSCR SECONDARY SIDE COOLING RECOVERY FAB FEED AND BLEED HPI HIGH PRESSURE INJECTION MFW MAIN FEEDWATER AFW AUXILIARY FEEDWATER RPS REACTOR PROTECTION SYSTEM IE-SLOCA SMALL LOCA END-STATE FREQUENCY 1
OK 2
OK 3
CD 4
OK 5
CD 6
CD 7
OK 8
OK 9
CD 10 OK 11 CD 12 CD 13 OK 14 OK 15 CD 16 OK 17 CD 18 OK 19 CD 20 CD 21 CD RHR1 RHR1 RHR1 SLOCA - WATTS BAR 1 & 2 PWR B SMALL LOCA 2005/01/28 Figure A-4. SLOCA - Watts Bar 1 and 2 PWR B Small LOCA
IR 05000390/2004005 20 IE-LOCCW 193 IE-LOCCW-A 198 IE-LOCCW-B LOSS OF COMPONENT COOLING WATER TRAIN 1A LOSS OF COMPONENT COOLING WATER TRAIN 1B/2B TOTAL LOSS OF COMPONENT COOLING WATER SYSTEM IE-LOCCW - TOTAL LOSS OF COMPONENT COOLING 2005/08/18 Page 185 Figure A-5. IE-LOCCW - Total Loss of Component Cooling
IR 05000390/2004005 21 IE-LOCCW-A 2.628E-4 IE-CCW-HTX-PG-HXA IGNORE IE-CCW-PSF-FC-TNKA 194 IE-LOCCW-A-ARBS 195 IE-LOCCW-A-ASBR 4.440E-5 IE-CCW-CF-HXPL-AANDC 8.756E-4 IE-CCW-HTX-FOUL-HXA IE-CCW-TRNA-HTX-FOULING 7.200E-6 IE-CCW-HTX-FOUL-HXB IE-CCW-HTXB-FOULING 6.500E-3 IE-CCW-XHE-XM-HXB CCW HEAT EXCHANGER HX A PLUGS LOSS OF CCW FLOW:
PUMP 1A-A RUNNING, PUMP 1B-B STANDBY LOSS OF CCW FLOW:
PUMP 1A-A STANDBY, PUMP 1B-B RUNNING CCW RELIEF VALVE, SURGE TANK, AND PASSIVE PIPING FAILURES LOSS OF COMPONENT COOLING WATER TRAIN 1A CCF OF CCW HEAT EXCHANGERS A AND C PLUG CCW HEAT EXCHANGER A FOULS CCW HEAT EXCHANGER HX B FOULS CCW TRAIN A HTX NOT AVAILABLE DUE TO FOULING OR FAILURE TO UTILIZE CCW HTX B NOT AVAILABLE DUE TO FOULING OF FAILURE TO UTILIZE CCW HEATEXCHANGER NOT UTILIZED (INITIATING EVENT)
IE-LOCCW-A - PARTIAL LOSS OF COMPONENT COOLING 2005/08/18 Page 193 Figure A-6. IE-LOCCW-A - Partial Loss of Component Cooling
IR 05000390/2004005 22 IE-LOCCW-B 2.160E-6 CCW-HTX-PG-HXC-LCO 1.300E-6 CCW-PSF-FC-TNKB 186 IE-LOCCW-B-CRBS 187 IE-LOCCW-B-CSBR 4.440E-5 IE-CCW-CF-HXPL-AANDC 7.200E-6 IE-CCW-HTX-FOUL-HXC CCW RELIEF VALVE, SURGE TANK, AND PASSIVE PIPING FAILURES LOSS OF COMPONENT COOLING WATER TRAIN 1B/2B CCW HEAT EXCHANGER HX C PLUGS DURING LCO LOSS OF CCW: PUMP C-S RUNNING, PUMP 2B-B STANDBY LOSS OF CCW: PUMP C-S STANDBY, PUMP 2B-B RUNNING CCF OF CCW HEAT EXCHANGERS A AND C PLUG CCW HEAT EXCHANGER HX C FOULS IE-LOCCW-B - WATTS BAR 1 & 2 PWR B CCW SYSTEM TRAIN B FAILS 2005/08/02 Page 198 Figure A-7. IE-LOCCW-B - Watts Bar 1 and 2 PWR B CCW System Train B Fails
IR 05000390/2004005 23 CCW-A 139 SWS-CCWA CCWA-MDPS 234 CCW-MDP-1AA 26 CCW-MDP-1BB 7.200E-7 CCW-HTX-PG-HXA IGNORE CCW-MOV-OC-1702 IGNORE CCW-MOV-OC-7025 1.300E-6 CCW-PSF-FC-TNKA IGNORE CW-MOV-OC-7012 1.217E-7 CCW-HTX-CF-HXAC CCW-TRNA-HTX-FOULING 2.400E-6 CCW-HTX-FOUL-HXA CCW-HTXB-FOULING 2.400E-6 CCW-HTX-FOUL-HXB 3.250E-2 CCW-XHE-XM-HXB 1.690E-1 CCW-HTX-CF-FOUL2-2 CCW MDP 1BB FAILURES CCW TRAIN A FAILURES COMPONENT COOLING WATER TRAIN A FAILS TO PROVIDE FLOW CCW RELIEF VALVE AND PASSIVE PIPING FAILURES CCW HEAT EXCHANGER HXA PLUGS FAILURE OF CCW HEADER A MOV 1-70-2 FAILURE OF CCW HEADER A MOV 70-25 FAILURE OF CCW HEADER A MOV 70-12 CCF OF CCW HEAT EXCHANGERS HX-A & C CCW-A MDP 1AA FAILURES SWS-A FAILS TO PROVIDE FLOW TO SWS HDR A - CCW A CCW TRAIN A HTX NOT AVAILABLE DUE TO FOULING OR FAILURE TO UTILIZE SPARE CCW HEATEXCHANGER HTXA FOULS DURING MISSION CCW HTX B NOT AVAILABLE DUE TO FOLUING OR FAILURE TO UTILIZE CCW HEAT EXCHANGER B NOT UTILIZED CCF DUE TO FOULING OF 2 OF 2 CCW HTXS GIVEN 1 HAS FOULED CCW HEAT EXCHANGER HTXB FOULS DURING MISSION CCW-A - WATTS BAR 1 & 2 PWR B CCW SYSTEM A FAILS 2005/08/18 Page 23 Figure A-8. CCW-A - Watts Bar 1 and 2 PWR B CCW System A Fails
IR 05000390/2004005 24 CCW-A-RECIRC 139 SWS-CCWA CCWA-MDPS-R CCWA-MDP-AA CCWA-1AA-LOOP1 CCWA-1AA-FS-L1 3.031E-6 CCW-MDP-CF-STRT FALSE LOOP-A 9.600E-5 CCW-MDP-FR-1AA 26 CCW-MDP-1BB 7.200E-7 CCW-HTX-PG-HXA 9.279E-8 CCW-MDP-CF-RUN 2.171E-7 CCW-CKV-CF-PMPS IGNORE CCW-MOV-OC-1702 IGNORE CCW-MOV-OC-7025 1.300E-6 CCW-PSF-FC-TNKA 32 DCP-BD-I 1.500E-3 CCW-MDP-FS-1AA 1.000E-4 CCW-CKV-CC-1504A 6
ACP-SDBUS-1A 1.217E-7 CCW-HTX-CF-HXAC CCW-TRNA-HTX-FOULING 2.400E-6 CCW-HTX-FOUL-HXA 2.400E-6 CCW-HTX-FOUL-HXB 3.250E-2 CCW-XHE-XM-HXB CCW-HTXB-FOULING 1.690E-1 CCW-HTX-CF-FOUL2-2 CCW-A MDP 1AA FAILS DURING LOOP CCW-A MDP FAILS DURING LOOP CCW MDP 1BB FAILURES CCW-A MDP 1AA FAILURES CCW TRAIN A FAILURES CCW TRAIN A FAILS TO PROVIDE FLOW DURING RECIRC SWS A FAILS TO PROVIDE FLOW TO SWS HDR A - CCW A CCW MDP 1AA FAILS TO RUN CCF OF CCW DISCHARGE CHECK VALVES CCW RELIEF VALVE AND PASSIVE PIPING FAILURES CCF OF CCW MDPS TO START CCF OF CCW MDPS TO RUN CCW HEAT EXCHANGER HXA PLUGS LOSS OF OFFSITE POWER FLAG FAILURE OF CCW HEADER A MOV 1-70-2 FAILURE OF CCW HEADER A MOV 70-25 125 VDC BATTERY BOARD BD-I FAILS FAILURE OF CCW MDP 1AA TO START FAILURE OF CCW MDP 1AA DIS CKV 1504A TO OPEN 6.9KV SD BOARD 1A AC POWER FAILS CCF OF CCW HEAT EXCHANGERS HX-A & C CCW TRAIN A HTX NOT AVAILABLE DUE TO FOULING OR FAILURE TO UTILIZE SPARE CCW HEATEXCHANGER HTXA FOULS DURING MISSION CCW HTX B NOT AVAILABLE DUE TO FOLUING OR FAILURE TO UTILIZE CCW HEAT EXCHANGER B NOT UTILIZED CCF DUE TO FOULING OF 2 OF 2 CCW HTXS GIVEN 1 HAS FOULED CCW HEAT EXCHANGER HTXB FOULS DURING MISSION CCW -A-RECIRC - W ATTS BAR 1 & 2 PWR B CCW TRAIN A COOLING DURING RECIRC 2005/08/18 Page 24 Figure A-9. CCW-A-REC IRC - Watts Bar 1 and 2 PWR B CCW Train A Cooling During Recirc
IR 05000390/2004005 25 CCW-B 140 SWS-CCWB CCWB-MDPS 235 CCW-MDP-CS 27 CCW-MDP-2BB 7.200E-7 CCW-HTX-PG-HXC IGNORE CCW-MOV-OC-1703 IGNORE CCW-MOV-OC-7022 1.300E-6 CCW-PSF-FC-TNKB IGNORE CCW-MOV-OC-7012 1.217E-7 CCW-HTX-CF-HXAC 2.400E-6 CCW-HTX-FOUL-HXC CCW-B MDP FAILURES FAILURES OF CCW MDP 2BB COMPONENT COOLING WATER TRAIN B FAILS TO PROVIDE FLOW SWS B FAILS TO PROVIDE FLOW TO SWS HDR B - CCW B CCW HEAT EXCHANGER HXC PLUGS FAILURE OF CCW HEADER B MOV 1-70-3 FAILURE OF CCW HEADER B MOV 70-22 CCW RELIEF VALVE AND PASSIVE PIPING FAILURES FAILURE OF CCW HEADER A MOV 70-12 CCF OF CCW HEAT EXCHANGERS HX-A & C FAILURE OF CCW MDP CS CCW HEAT EXCHANGER HTX C FOULS DURING MISSION CCW-B - WATTS BAR 1 & 2 PW R B CCW SYSTEM B FAILS 2005/08/18 Page 25 Figure A-10. CCW-B - Watts Bar 1 and 2 PWR B CCW System B Fails
IR 05000390/2004005 26 1.200E-3 C-MDP-FS-1A 32 DCP-BD-I CVC-HTX-PG-OILA CVCA-SWS-CCWA 23 CCW-A CVCA-SWSAA 1.500E-1 CVS-XHE-XM-CPP1AA FALSE SWS-XVM-CC-1016B 137 SWS-A CVCA-SWSAA-HXPLUG CVCA-SWSAA-CCWHXPLUG TRUE CVCA-SWSA-PLUG-HOUSE 4.440E-5 IE-CCW-CF-HXPL-AANDC 1.217E-7 CCW-HTX-CF-HXAC ERCW HEADER A FAILS COMPONENT COOLING WATER TRAIN A FAILS TO PROVIDE FLOW 125 VDC BATTERY BOARD BD-I FAILS SWS-A FAILS TO PROVIDE FLOW TO SWS HDR A OPERATOR FAILS TO ALIGN ERCW TO CPP-1AA UPON LOSS OF CCW C MDP TRAIN FAILURE TO START ERCW MANUAL VALVE 67-1016B TO CPP-1AA OIL COOLER FAILS ERCW TO CCPA FAILS DUE TO PLUGGING COINCIDENT WITH PLUGGING OF CCW HXS CCF OF CCW HXS DUE TO PLUGGING CCF OF CCW HEAT EXCHANGERS A AND C PLUG CCF OF CCW HEAT EXCHANGERS HX-A & C HOUSE EVENT TO CAUSE ERCW FAIL WITH CCW HX PLUGGING CVC-MDPA - WATTS BAR 1 & 2 PW R B CHARGING TRAIN A FAILURES 2006/05/03 Page 30 Figure A-11. CVC-MDPA - Watts Bar 1 and 2 PWR B Charging Train A Failures
IR 05000390/2004005 27 CVCA-SWS-CCW 23 CCW-A CVCA-SWSA 137 SWS-A FALSE SWS-XVM-CC-1016B 1.500E-1 CVS-XHE-XM-CPP1AA 7.200E-7 CVC-HTX-PG-OILA CVCA-SWSAA-HXPLUG TRUE CVCA-SWSA-PLUG-HOUSE 4.440E-5 IE-CCW-CF-HXPL-AANDC 1.217E-7 CCW-HTX-CF-HXAC CVCA-SWSAA-CCWHXPLUG ERCW HEADER A FAILS COMPONENT COOLING WATER TRAIN A FAILS TO PROVIDE FLOW SWS-A FAILS TO PROVIDE FLOW TO SWS HDR A OPERATOR FAILS TO ALIGN ERCW TO CPP-1AA UPON LOSS OF CCW ERCW MANUAL VALVE 67-1016B TO CPP-1AA OIL COOLER FAILS ERCW TO CCPA FAILS DUE TO PLUGGING COINCIDENT WITH PLUGGING OF CCW HXS HOUSE EVENT TO CAUSE ERCW FAIL WITH CCW HX PLUGGING CCF OF CCW HEAT EXCHANGERS A AND C PLUG CCF OF CCW HEAT EXCHANGERS HX-A & C CCF OF CCW HXS DUE TO PLUGGING CVC-MDPS-SEAL - FAILURE OF CHARGING PUMPS FOR SEAL COOLING 2006/05/03 Page 183 Figure A-12. CVC-MDPS-SEAL - Failure of Charging Pumps for Seal Cooling
IR 05000390/2004005 IR 05000390/2004005 28 Table A-1 Additional Recovery Rules for LOCCW and LOCCW-A Sequences Recovery Rules for Sequences l Add common cause failures to the cutsets. The l CCF failure event is failure of 2-of-2 pumps to start if init(IE-D-LOCCW)*CCW-MDP-FS-1BB
- CCW-MDP-FS-2BB then CopyRoot; DeleteEvent = CCW-MDP-FS-1BB; DeleteEvent = CCW-MDP-FS-2BB; AddEvent = CCW-MDP-CF-STRT2-2; endif l
l CCF failure of 4-of-4 pumps to run, given that one has l failed.
l if init(IE-D-LOCCW)*CCW-MDP-FR-1BB-LCO
- CCW-MDP-FR-2BB-LCO
- CCW-MDP-FR-CS-LCO then CopyRoot; DeleteEvent = CCW-MDP-FR-1BB-LCO; DeleteEvent = CCW-MDP-FR-2BB-LCO; DeleteEvent = CCW-MDP-FR-CS-LCO; AddEvent = CCW-MDP-CF-RUN4-4; endif if init(IE-D-LOCCW)*CCW-MDP-FR-1AA-LCO
- CCW-MDP-FR-2BB-LCO
- CCW-MDP-FR-CS-LCO then CopyRoot; DeleteEvent = CCW-MDP-FR-1AA-LCO; DeleteEvent = CCW-MDP-FR-2BB-LCO; DeleteEvent = CCW-MDP-FR-CS-LCO; AddEvent = CCW-MDP-CF-RUN4-4; endif l
if FLAG-CCW-1A-RUNNING
- FLAG-CCW-1B-RUNNING then DeleteRoot; endif l
if FLAG-CCW-CS-RUNNING
- FLAG-CCW-2B-RUNNING then DeleteRoot; endif l
IR 05000390/2004005 IR 05000390/2004005 Table A-1 Additional Recovery Rules for LOCCW and LOCCW-A Sequences Recovery Rules for Sequences 29 lCCf of 3 of 3 CCW hx due to fouling l
if init(IE-D-LOCCW)*IE-CCW-HTX-FOUL-HXA
- IE-CCW-HTX-FOUL-HXB
- IE-CCW-HTX-FOUL-HXC then Copyroot; DeleteEvent = IE-CCW-HTX-FOUL-HXB; DeleteEvent = IE-CCW-HTX-FOUL-HXC; AddEvent = CCW-HTX-CF-FOUL3-3; endif l
lCCF of 2 of 2 CCW HX due to fouling l
if init(IE-D-LOCCW)*IE-CCW-HTX-FOUL-HXA
- IE-CCW-HTX-FOUL-HXC then Copyroot; DeleteEvent = IE-CCW-HTX-FOUL-HXC; AddEvent = CCW-HTX-CF-FOUL2-2; endif l This rule adds common cause failures to the cutsets. The l CCF failure event is failure of 2-of-2 pumps to run given l that one pump is known to be failed.
l if init(IE-D-LOCCW-A)*IE-CCW-MDP-FR-1AA*CCW-MDP-FR-1BB-LCO then CopyRoot; DeleteEvent = CCW-MDP-FR-1BB-LCO; AddEvent = CCW-MDP-CF-RUN2-2; endif if init(IE-D-LOCCW-A)*IE-CCW-MDP-FR-1BB*CCW-MDP-FR-1AA-LCO then CopyRoot; DeleteEvent = CCW-MDP-FR-1AA-LCO; AddEvent = CCW-MDP-CF-RUN2-2; endif l
lCCF of 2 of 2 HX due to fouling l
if init(IE-D-LOCCW-A)*IE-CCW-HTX-FOUL-HXA*IE-CCW-HTX-FOUL-HXB then CopyRoot;
IR 05000390/2004005 IR 05000390/2004005 Table A-1 Additional Recovery Rules for LOCCW and LOCCW-A Sequences Recovery Rules for Sequences DeleteEvent = IE-CCW-HTX-FOUL-HXB; AddEvent = CCW-HTX-CF-FOUL2-2; endif if init(IE-D-LOCCW-A)* IE-CCW-CF-HXPL-AANDC then DeleteRoot; endif Appendix B Human Reliability Modeling
IR 05000390/2004005 IR 05000390/2004005 31 SPAR Model Human Error Worksheet (Page 1 of 3)
Plant: WBNP Event Name: IE-CCW-XHE-XM-HXB Task Error
Description:
CCW HEAT EXCHANGER B NOT UTILIZED AFTER FOULING OF HX A (INITIATING EVENT)
Does this task contain a significant amount of diagnosis activity ? YES X NO If Yes, Use Table 1 below to evaluate the PSFs for the Diagnosis portion of the task before going to Table 2. If No, go directly to Table 2.
Table 1. Diagnosis worksheet.
PSFs PSF Levels Multiplier for Diagnosis If non-nominal PSF levels are selected, please note specific reasons in this column
- 1. Available Time Inadequate 1.0a Fouling assumed to be gradual and have several shifts to discover.
Barely adequate < 20 m 10 Nominal. 30 m 1
Extra > 60 m 0.1T Expansive > 24 h 0.01
- 2. Stress Extreme 5
Prior to initiating event hence no stress.
High 2
Nominal 1T
- 3. Complexity Highly 5
Moderately 2
Nominal 1T
- 4. Experience/
Training Low 10T Unusual event.
Nominal 1
High 0.5
- 5. Procedures Not available 50 Assumed.
Available, but poor 5T Nominal 1
Diagnostic/symptom oriented 0.5
- 6. Ergonomics Missing/Misleading 50 Poor 10 Nominal 1T Good 0.5
- 7. Fitness for Duty Unfit 1.0a Degraded Fitness 5
Nominal 1T
- 8. Work Processes Poor 2
Nominal 1T Good 0.8
- a. Task failure probability is 1.0 regardless of other PSFs.
IR 05000390/2004005 IR 05000390/2004005 32 SPAR Model Human Error Worksheet (Page 2 of 3)
Table 2. Action worksheet.
PSFs PSF Levels Multiplier for Action If non-nominal PSF levels are selected, please note specific reasons in this column
- 1. Available Time Inadequate 1.0a Fouling is gradual and while may take an hour or so to execute several hours are available.
Time available. time required 10 Nominal 1
Available > 5x time required 0.1T Available > 50x time required 0.01
- 2. Stress Extreme 5
High 2
Nominal 1 T
- 3. Complexity Highly 5
Moderately 2
Nominal 1T
- 4. Experience/
Training Low 3T Not. a usual operation Nominal 1
High 0.5
- 5. Procedures Not available 50 Assumed Available, but poor 5T Nominal 1
- 6. Ergonomics Missing/Misleading 50 Poor 10 Nominal 1T Good 0.5
- 7. Fitness for Duty Unfit 1.0a Degraded Fitness 5
Nominal 1T
- 8. Work Processes Poor 2
Nominal 1T Good 0.8
- a. Task failure probability is 1.0 regardless of other PSFs.
Table 3. Task failure probability without formal dependence worksheet.
Task Portion Nom.
Prob.
Time Stress Compl.
Exper./
Train.
Proced.
Ergon.
Fitness Work Process Prob.
Diag.
1.0E-2 x 0.01 x 1.0 X 1.0 X 10.0 X 5.0 x 1.0 x 1.0 x 1.0 5.0E-3 Action 1.0E-3 x 0.1 x 1.0 x 1.0 x 3.0 x 5.0 x 1.0 x 1.0 x 1.0 1.5E-3 Total 6.50E-3
IR 05000390/2004005 IR 05000390/2004005 33 SPAR Model Human Error Worksheet (Page 3 of 3)
For all tasks, except the first task in the sequence, use the table and formulae below to calculate the Task Failure Probability With Formal Dependence.
Table 4. Dependency condition worksheet.
Condition Number Crew (same or different)
Location (same or different)
Time (close in time or not close in time)
Cues (additional or not additional)
Dependency Number of Human Action Failures Rule 1
s s
c complete If this error is the 3rd error in the sequence, then the dependency is at least moderate.
If this error is the 4th error in the sequence, then the dependency is at least high.
This rule may be ignored only if there is compelling evidence for less dependence with the previous tasks.
2 s
s nc na high 3
s s
nc a
moderate 4
s d
c high 5
s d
nc na moderate 6
s d
nc a
low 7
d s
c moderate 8
d s
nc na low 9
d s
nc a
low 10 d
d c
moderate 11 d
d nc na low 12 d
d nc a
low 13 zero Using P = Task Failure Probability Without Formal Dependence (calculated on Page 2):
For Complete Dependence the probability of failure
= 1.0 For High Dependence the probability of failure
= (1 + P)/2 For Moderate Dependence the probability of failure
= (1 +6P)/7 For Low Dependence the probability of failure
= (1 + 19P)/20 T
For Zero Dependence the probability of failure
P Task Failure Probability With Formal Dependence = (1 + ( * )) /
Additional Notes:
IR 05000390/2004005 IR 05000390/2004005 34 SPAR Model Human Error Worksheet (Page 1 of 3)
Plant: WBNP Event Name: CCW-XHE-XM-HXB Task Error
Description:
CCW HEAT EXCHANGER B NOT UTILIZED AFTER FOULING OF HX A Does this task contain a significant amount of diagnosis activity ? YES X NO If Yes, Use Table 1 below to evaluate the PSFs for the Diagnosis portion of the task before going to Table 2. If No, go directly to Table 2.
Table 1. Diagnosis worksheet.
PSFs PSF Levels Multiplier for Diagnosis If non-nominal PSF levels are selected, please note specific reasons in this column
- 1. Available Time Inadequate 1.0a Fouling assumed to be gradual and have several shifts to discover.
Barely adequate < 20 m 10 Nominal. 30 m 1
Extra > 60 m 0.1T Expansive > 24 h 0.01
- 2. Stress Extreme 5T After an initiating event hence stress.
High 2
Nominal 1
- 3. Complexity Highly 5
Moderately 2
Nominal 1T
- 4. Experience/
Training Low 10T Unusual event.
Nominal 1
High 0.5
- 5. Procedures Not available 50 Assumed.
Available, but poor 5T Nominal 1
Diagnostic/symptom oriented 0.5
- 6. Ergonomics Missing/Misleading 50 Poor 10 Nominal 1T Good 0.5
- 7. Fitness for Duty Unfit 1.0a Degraded Fitness 5
Nominal 1T
- 8. Work Processes Poor 2
Nominal 1T Good 0.8
- a. Task failure probability is 1.0 regardless of other PSFs.
IR 05000390/2004005 IR 05000390/2004005 35 SPAR Model Human Error Worksheet (Page 2 of 3)
Table 2. Action worksheet.
PSFs PSF Levels Multiplier for Action If non-nominal PSF levels are selected, please note specific reasons in this column
- 1. Available Time Inadequate 1.0a Fouling is gradual and while may take an hour or so to execute several hours are available.
Time available. time required 10 Nominal 1
Available > 5x time required 0.1T Available > 50x time required 0.01
- 2. Stress Extreme 5 T After an initiating event hence stress.
High 2
Nominal 1
- 3. Complexity Highly 5
Moderately 2
Nominal 1T
- 4. Experience/
Training Low 3T Not. a usual operation.
Nominal 1
High 0.5
- 5. Procedures Not available 50 Assumed.
Available, but poor 5T Nominal 1
- 6. Ergonomics Missing/Misleading 50 Poor 10 Nominal 1T Good 0.5
- 7. Fitness for Duty Unfit 1.0a Degraded Fitness 5
Nominal 1T
- 8. Work Processes Poor 2
Nominal 1T Good 0.8
- a. Task failure probability is 1.0 regardless of other PSFs.
Table 3. Task failure probability without formal dependence worksheet.
Task Portion Nom.
Prob.
Time Stress Compl.
Exper./
Train.
Proced.
Ergon.
Fitness Work Process Prob.
Diag.
1.0E-2 x 0.01 x 5.0 X 1.0 X 10.0 X 5.0 2.5E-2 Action 1.0E-3 x 0.1 x 5.0 x 1.0 x 3.0 x 5.0 x 1.0 x 1.0 x 1.0 7.5E-3 Total 3.25E-2
IR 05000390/2004005 IR 05000390/2004005 36 SPAR Model Human Error Worksheet (Page 3 of 3)
For all tasks, except the first task in the sequence, use the table and formulae below to calculate the Task Failure Probability With Formal Dependence.
Table 4. Dependency condition worksheet.
Condition Number Crew (same or different)
Location (same or different)
Time (close in time or not close in time)
Cues (additional or not additional)
Dependency Number of Human Action Failures Rule 1
s s
c complete If this error is the 3rd error in the sequence, then the dependency is at least moderate.
If this error is the 4th error in the sequence, then the dependency is at least high.
This rule may be ignored only if there is compelling evidence for less dependence with the previous tasks.
2 s
s nc na high 3
s s
nc a
moderate 4
s d
c high 5
s d
nc na moderate 6
s d
nc a
low 7
d s
c moderate 8
d s
nc na low 9
d s
nc a
low 10 d
d c
moderate 11 d
d nc na low 12 d
d nc a
low 13 zero Using P = Task Failure Probability Without Formal Dependence (calculated on Page 2):
For Complete Dependence the probability of failure
= 1.0 For High Dependence the probability of failure
= (1 + P)/2 For Moderate Dependence the probability of failure
= (1 +6P)/7 For Low Dependence the probability of failure
= (1 + 19P)/20 For Zero Dependence the probability of failure
P Task Failure Probability With Formal Dependence = (1 + ( * )) /
Additional Notes:
IR 05000390/2004005 IR 05000390/2004005 Appendix C GEM Summary Report
IR 05000390/2004005 IR 05000390/2004005 38 C O N D I T I O N A S S E S S M E N T Code Version: 7:26 Model Version : 2005/08/12 Project : WBAR_3+IEFT Duration (hrs) : 6.0E+003 User Name : IDAHO NATIONAL LABORATORY Total CCDP : 8.8E-005 Event ID : ERCWXT Total CDP : 8.0E-005 Importance : 7.5E-006 Description : ERCW SUPPLY TO CHARGING PUMPS IS UNAVAILABLE BASIC EVENT CHANGES Event Name Description Base Prob Curr Prob Type CVS-XHE-XM-CPP1AA OPERATOR FAILS TO ALIGN ERCW 1.5E-001 1.0E+000 TRUE SEQUENCE PROBABILITIES Truncation : Cummulative : 100.0% Individual : 0.0%
Event Tree Name Sequence Name CCDP CDP Importance LOCCW 3-02-06 1.4E-005 7.3E-006 6.9E-006 LOCCW 3-03-06 7.2E-007 3.4E-007 3.8E-007 LOCCW 3-04-3 1.8E-007 8.5E-008 9.4E-008 LODCB 02-02-06 6.2E-008 1.2E-008 4.9E-008 LOCCW-A 3-02-03 9.8E-008 6.0E-008 3.8E-008 LOCCW-A 3-02-06 3.6E-008 6.3E-009 2.9E-008 LOCCW-A 3-04-3 2.2E-008 3.3E-009 1.8E-008 LOOP 02-05 1.7E-008 4.5E-009 1.3E-008 NEGATIVE SEQUENCE PROBABILITIES Truncation : Cummulative : 100.0% Individual : 0.0%
Event Tree Name Sequence Name CCDP CDP Importance NOTE: Percent contribution to total Importance.
SEQUENCE LOGIC Event Tree Sequence Name Logic LOCCW 3-02-06 IE-LOCCW /RPS
/AFW LOSC
/RCPT /RSD
/BP1 BP2 HPI LOCCW 3-03-06 IE-LOCCW /RPS 2006/05/02 10:51:35 page 1
IR 05000390/2004005 IR 05000390/2004005 39
/AFW LOSC
/RCPT /RSD BP1 /BP2 HPI LOCCW 3-04-3 IE-LOCCW /RPS
/AFW LOSC
/RCPT /RSD BP1 BP2
/ACC-M HPI-M LODCB 02-02-06 /RPS /AFW
/PORV LOSC
/RCPT /RSD
/BP1 BP2 HPI LOCCW-A 3-02-03 IE-LOCCW-A /RPS
/AFW LOSC
/RCPT /RSD
/BP1 BP2
/HPI /PZR RHR1 HPR LOCCW-A 3-02-06 IE-LOCCW-A /RPS
/AFW LOSC
/RCPT /RSD
/BP1 BP2 HPI LOCCW-A 3-04-3 IE-LOCCW-A /RPS
/AFW LOSC
/RCPT /RSD BP1 BP2
/ACC-M HPI-M LOOP 02-05 /RPS /EPS
/AFW-L /PORV-L LOSC-L /RSD
/BP1 BP2 OPR-02H HPI-L Fault Tree Name Description ACC-M ACCUMULATOR 2-OF-3 AFW AUXILIARY FEEDWATER AFW-L AUXILIARY FEEDWATER DURING LOOP BP1 RCP SEAL STAGE 1 INTEGRITY (BINDING/POPPING)
BP2 RCP SEAL STAGE 2 INTEGRITY (BINDING/POPPING)
EPS EMERGENCY POWER HPI HIGH PRESSURE INJECTION 2006/05/02 10:51:35 page 2
IR 05000390/2004005 IR 05000390/2004005 40 HPI-L HIGH PRESSURE INJECTION HPI-M HIGH PRESSURE INJECTION 2/4 TRAINS HPR HIGH PRESSURE RECIRC IE-LOCCW TOTAL LOSS OF COMPONENT COOLING IE-LOCCW-A PARTIAL LOSS OF COMPONENT COOLING LOSC RCP SEAL COOLING MAINTAINED LOSC-L LOSS OF SEAL COOLING DURING LOOP OPR-02H OFFSITE POWER RECOVERY IN 2 HRS PORV PORVs ARE CLOSED PORV-L PORVS ARE CLOSED DURING LOOP PZR RCS DEPRESS FOR RHR RCPT REACTOR COOLANT PUMPS TRIPPED RHR1 WATTS BAR 1 & 2 PWR B RESIDUAL HEAT REMOVAL (SLOCA)
RPS REACTOR PROTECTION SYSTEM RSD RAPID SECONDARY DEPRESSURIZATION (<1710 PSI IN 2 HR)
SEQUENCE CUT SETS Truncation: Cummulative: 100.0% Individual: 1.0%
Event Tree: LOCCW CCDF: 2.1E-005 Sequence: 3-02-06 CCDF % Cut Set Cut Set Events 8.8E-006 42.58 /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-CF-HXPL-AANDC 5.0E-006 24.01 /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-FOUL-HXA CCW-HTX-CF-FOUL3-3 3.3E-006 16.22 /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN4-4 3.3E-006 16.22 /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN4-4 Event Tree: LOCCW CCDF: 1.0E-006 Sequence: 3-03-06 CCDF % Cut Set Cut Set Events 4.4E-007 42.58 RCS-MDP-LK-BP1 /RCS-MDP-LK-BP2 IE-CCW-CF-HXPL-AANDC 2.5E-007 24.01 RCS-MDP-LK-BP1 /RCS-MDP-LK-BP2 IE-CCW-HTX-FOUL-HXA CCW-HTX-CF-FOUL3-3 1.7E-007 16.22 RCS-MDP-LK-BP1 /RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN4-4 1.7E-007 16.22 RCS-MDP-LK-BP1 /RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING 2006/05/02 10:51:35 page 3
IR 05000390/2004005 IR 05000390/2004005 41 CCW-XHE-XL-1BB CCW-MDP-CF-RUN4-4 Event Tree: LOCCW CCDF: 2.6E-007 Sequence: 3-04-3 CCDF % Cut Set Cut Set Events 1.1E-007 42.58 RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-CF-HXPL-AANDC 6.3E-008 24.01 RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-FOUL-HXA CCW-HTX-CF-FOUL3-3 4.2E-008 16.22 RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN4-4 4.2E-008 16.22 RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN4-4 Event Tree: LODCB CCDF: 9.0E-008 Sequence: 02-02-06 CCDF % Cut Set Cut Set Events 4.7E-008 52.93 CCW-MDP-FR-1AA /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 3.6E-008 39.70 SWS-STR-PG-A2AA /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 2.4E-009 2.65 ACP-BAC-LP-1A /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 1.8E-009 2.03 SWS-STR-CF-ALL /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 Event Tree: LOCCW-A CCDF: 1.4E-007 Sequence: 3-02-03 CCDF % Cut Set Cut Set Events 5.3E-009 3.73 RHR-MDP-TM-1B CVC-XHE-XM-VCTSWAP
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-XHE-XL-LTRF CCW-MDP-CF-RUN2-2 5.3E-009 3.73 RHR-MDP-TM-1B CVC-XHE-XM-VCTSWAP
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-XHE-XL-LTRF CCW-MDP-CF-RUN2-2 3.1E-009 2.18 RHR-MDP-TM-1B CVC-XHE-XM-VCTSWAP
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-PG-HXA CCW-XHE-XL-LTRF 2.7E-009 1.86 CVC-MDP-TM-1B RHR-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 2006/05/02 10:51:35 page 4
IR 05000390/2004005 IR 05000390/2004005 42 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-XHE-XL-LTRF CCW-MDP-CF-RUN2-2 2.7E-009 1.86 CVC-MDP-TM-1B RHR-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-XHE-XL-LTRF CCW-MDP-CF-RUN2-2 2.2E-009 1.55 CVC-XHE-XM-VCTSWAP RHR-HTX-TM-HXB
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-XHE-XL-LTRF CCW-MDP-CF-RUN2-2 2.2E-009 1.55 CVC-XHE-XM-VCTSWAP RHR-HTX-TM-HXB
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-XHE-XL-LTRF CCW-MDP-CF-RUN2-2 1.8E-009 1.24 CVC-XHE-XM-VCTSWAP RHR-FAN-TM-RHRRMB
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-XHE-XL-LTRF CCW-MDP-CF-RUN2-2 1.8E-009 1.24 HPR-XHE-XM CVC-XHE-XM-VCTSWAP
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN2-2 1.8E-009 1.24 CVC-XHE-XM-VCTSWAP RHR-FAN-TM-RHRRMB
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-XHE-XL-LTRF CCW-MDP-CF-RUN2-2 1.8E-009 1.24 HPR-XHE-XM CVC-XHE-XM-VCTSWAP
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN2-2 1.8E-009 1.23 RHR-MDP-TM-1B CVC-XHE-XM-VCTSWAP
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 CCW-XHE-XL-LTRF IE-CCW-HTX-FOUL-HXA CCW-HTX-CF-FOUL2-2 1.7E-009 1.16 RHR-MDP-TM-1B CVC-XHE-XM-VCTSWAP
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-MDP-TM-1AA CCW-XHE-XL-1BB CCW-XHE-XL-LTRF 1.7E-009 1.16 RHR-MDP-TM-1B CVC-XHE-XM-VCTSWAP CCW-MDP-TM-1BB /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-XHE-XL-LTRF 1.6E-009 1.09 CVC-MDP-TM-1B RHR-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 2006/05/02 10:51:35 page 5
IR 05000390/2004005 IR 05000390/2004005 43 IE-CCW-HTX-PG-HXA CCW-XHE-XL-LTRF Event Tree: LOCCW-A CCDF: 5.2E-008 Sequence: 3-02-06 CCDF % Cut Set Cut Set Events 6.4E-009 12.32 SWS-STR-PG-B2BB /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN2-2 6.4E-009 12.32 SWS-STR-PG-B2BB /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN2-2 3.7E-009 7.20 SWS-STR-PG-B2BB /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-PG-HXA 2.2E-009 4.28 CVC-MDP-TM-1B HPI-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN2-2 2.2E-009 4.28 CVC-MDP-TM-1B HPI-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN2-2 2.1E-009 4.05 SWS-STR-PG-B2BB /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-FOUL-HXA CCW-HTX-CF-FOUL2-2 2.0E-009 3.84 SWS-STR-PG-B2BB CCW-MDP-TM-1BB
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA 2.0E-009 3.84 SWS-STR-PG-B2BB /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-MDP-TM-1AA CCW-XHE-XL-1BB 1.3E-009 2.50 CVC-MDP-TM-1B HPI-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-PG-HXA 7.3E-010 1.41 CVC-MDP-TM-1B HPI-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-FOUL-HXA CCW-HTX-CF-FOUL2-2 6.9E-010 1.33 CVC-MDP-TM-1B HPI-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-MDP-TM-1AA CCW-XHE-XL-1BB 6.9E-010 1.33 CVC-MDP-TM-1B HPI-MDP-TM-1B CCW-MDP-TM-1BB /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA 5.3E-010 1.03 CVC-MDP-TM-1B HPI-MDP-FS-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 2006/05/02 10:51:35 page 6
IR 05000390/2004005 IR 05000390/2004005 44 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN2-2 5.3E-010 1.03 CVC-MDP-FS-1B HPI-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN2-2 5.3E-010 1.03 CVC-MDP-FS-1B HPI-MDP-TM-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN2-2 5.3E-010 1.03 CVC-MDP-TM-1B HPI-MDP-FS-1B
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN2-2 Event Tree: LOCCW-A CCDF: 3.2E-008 Sequence: 3-04-3 CCDF % Cut Set Cut Set Events 5.6E-009 17.86 CVC-MDP-TM-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN2-2 5.6E-009 17.86 CVC-MDP-TM-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN2-2 3.3E-009 10.44 CVC-MDP-TM-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-PG-HXA 1.9E-009 5.88 CVC-MDP-TM-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-FOUL-HXA CCW-HTX-CF-FOUL2-2 1.8E-009 5.56 CVC-MDP-TM-1B CCW-MDP-TM-1BB RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA 1.8E-009 5.56 CVC-MDP-TM-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-MDP-TM-1AA CCW-XHE-XL-1BB 1.4E-009 4.29 CVC-MDP-FS-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN2-2 1.4E-009 4.29 CVC-MDP-FS-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA CCW-MDP-CF-RUN2-2 1.1E-009 3.57 CVC-XHE-XR-MDPB RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA 2006/05/02 10:51:35 page 7
IR 05000390/2004005 IR 05000390/2004005 45 CCW-MDP-CF-RUN2-2 1.1E-009 3.57 CVC-XHE-XR-MDPB RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB CCW-MDP-CF-RUN2-2 7.9E-010 2.50 CVC-MDP-FS-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-PG-HXA 6.6E-010 2.09 CVC-XHE-XR-MDPB RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-PG-HXA 4.4E-010 1.41 CVC-MDP-FS-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-FOUL-HXA CCW-HTX-CF-FOUL2-2 4.2E-010 1.33 CVC-MDP-FS-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-MDP-TM-1AA CCW-XHE-XL-1BB 4.2E-010 1.33 CVC-MDP-FS-1B CCW-MDP-TM-1BB RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA 3.7E-010 1.18 CVC-XHE-XR-MDPB RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-HTX-FOUL-HXA CCW-HTX-CF-FOUL2-2 3.5E-010 1.11 CCW-MDP-TM-1BB CVC-XHE-XR-MDPB RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA 3.5E-010 1.11 CVC-XHE-XR-MDPB RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-MDP-TM-1AA CCW-XHE-XL-1BB 3.3E-010 1.04 CCW-MDP-FS-1AA CVC-MDP-TM-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1BB FLAG-CCW-1B-RUNNING CCW-XHE-XL-1BB 3.3E-010 1.04 CCW-MDP-FS-1BB CVC-MDP-TM-1B RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 IE-CCW-MDP-FR-1AA FLAG-CCW-1A-RUNNING CCW-XHE-XL-1AA Event Tree: LOOP CCDF: 2.5E-008 Sequence: 02-05 CCDF % Cut Set Cut Set Events 7.4E-009 29.16 CCW-MDP-CF-STRT OEP-XHE-XL-NR02H
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 1.6E-009 6.34 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-FR-2A EPS-DGN-FR-1B OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 1.6E-009 6.34 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA 2006/05/02 10:51:35 page 8
IR 05000390/2004005 IR 05000390/2004005 46 EPS-DGN-FR-2B EPS-DGN-FR-1B OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 1.6E-009 6.11 EPS-XHE-XL-UNIT1 CCW-MDP-FS-1AA EPS-DGN-FR-1B OEP-XHE-XL-NR02H
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 6.8E-010 2.70 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-TM-2B EPS-DGN-FR-1B OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 6.8E-010 2.70 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-FR-2B EPS-DGN-TM-1B OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 6.8E-010 2.70 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-TM-1B EPS-DGN-FR-2A OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 6.8E-010 2.70 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-TM-2A EPS-DGN-FR-1B OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 6.6E-010 2.60 EPS-XHE-XL-UNIT1 CCW-MDP-FS-1AA EPS-DGN-TM-1B OEP-XHE-XL-NR02H
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 5.3E-010 2.09 CCW-CKV-CF-PMPS OEP-XHE-XL-NR02H
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 3.0E-010 1.20 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-FS-2A EPS-DGN-FR-1B OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 3.0E-010 1.20 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-FS-1B EPS-DGN-FR-2A OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 3.0E-010 1.20 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-FS-2B EPS-DGN-FR-1B OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 3.0E-010 1.20 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-FS-1B EPS-DGN-FR-2B OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 3.0E-010 1.17 CCW-HTX-CF-HXAC OEP-XHE-XL-NR02H
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 2.9E-010 1.15 EPS-XHE-XL-UNIT1 CCW-MDP-FS-1AA EPS-DGN-FS-1B OEP-XHE-XL-NR02H
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 2.9E-010 1.15 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-TM-1B EPS-DGN-TM-2B OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 2006/05/02 10:51:35 page 9
IR 05000390/2004005 IR 05000390/2004005 47 2.9E-010 1.15 EPS-XHE-XL-UNIT2 CCW-MDP-FS-1AA EPS-DGN-TM-1B EPS-DGN-TM-2A OEP-XHE-XL-NR02H /RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 2.6E-010 1.02 SWS-STR-PG-A2AA SWS-MDP-FS-LB EPS-XHE-XL-UNIT2 OEP-XHE-XL-NR02H
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 2.6E-010 1.02 SWS-STR-PG-A2AA EPS-XHE-XL-UNIT2 SWS-MDP-FS-HB OEP-XHE-XL-NR02H
/RCS-MDP-LK-BP1 RCS-MDP-LK-BP2 BASIC EVENTS (Cut Sets Only)
Event Name Description Curr Prob ACP-BAC-LP-1A DIVISION 1A AC POWER 6.9KV BUS FAILS 4.8E-006 CCW-CKV-CF-PMPS CCF OF CCW DISCHARGE CHECK VALVES 2.2E-007 CCW-HTX-CF-FOUL2-2 CCF DUE TO FOULING OF 2 OF 2 CCW HTXS GIVEN 1 1.7E-001 CCW-HTX-CF-FOUL3-3 CCF DUE TO FOULING OF 3 OF 3 CCW HTX GIVEN 1 2.9E-002 CCW-HTX-CF-HXAC CCF OF CCW HEAT EXCHANGERS HX-A & C 1.2E-007 CCW-MDP-CF-RUN2-2 CCF OF 2-OF-2 CCW PUMPS TO RUN GIVEN 1 FAILED 2.6E-002 CCW-MDP-CF-RUN4-4 CCF OF 4-OF-4 CCW PUMPS TO RUN GIVEN 1 FAILED 9.7E-004 CCW-MDP-CF-STRT CCF OF CCW MDPS TO START 3.0E-006 CCW-MDP-FR-1AA CCW MDP 1AA FAILS TO RUN 9.6E-005 CCW-MDP-FS-1AA FAILURE OF CCW MDP 1AA TO START 1.5E-003 CCW-MDP-FS-1BB FAILURE OF CCW MDP 1BB TO START 1.5E-003 CCW-MDP-TM-1AA CCW PUMP 1A-A UNAVAILABLE DUE TO TEST AND MAI 8.0E-003 CCW-MDP-TM-1BB CCW MDP 1BB UNAVAILABLE DUE TO TEST AND MAINT 8.0E-003 CCW-XHE-XL-1AA OPERATOR FAILS TO RECOVER CCW PUMP 1A-A 1.0E+000 CCW-XHE-XL-1BB OPERATOR FAILS TO RECOVER CCW PUMP 1B-B 1.0E+000 CCW-XHE-XL-LTRF OPERATOR FAILS TO RECOVER CCW FOR LONG TERM D 1.0E+000 CVC-MDP-FS-1B CVC MDP TRAIN B FAILURE TO START 1.2E-003 CVC-MDP-TM-1B CHARGING PUMP 1B UNAVAILABLE DUE TO TEST AND 5.0E-003 CVC-XHE-XM-VCTSWAP OPERATOR FAILS TO SWAP SUCTION FROM VCT TO RW 1.0E-002 CVC-XHE-XR-MDPB OPERATOR FAILS TO RESTORE CHARGING PUMP 1B AF 1.0E-003 EPS-DGN-FR-1B DIESEL GENERATOR B FAILS TO RUN 2.1E-002 EPS-DGN-FR-2A DIESEL GENERATOR A FAILS TO RUN 2.1E-002 EPS-DGN-FR-2B DIESEL GENERATOR 2B FAILS TO RUN 2.1E-002 EPS-DGN-FS-1B DIESEL GENERATOR B FAILS TO START 4.0E-003 EPS-DGN-FS-2A DIESEL GENERATOR A FAILS TO START 4.0E-003 EPS-DGN-FS-2B DIESEL GENERATOR 2B FAILS TO START 4.0E-003 EPS-DGN-TM-1B DIESEL GENERATOR B UNAVAILABLE DUE TO TEST AN 9.0E-003 EPS-DGN-TM-2A DIESEL GENERATOR A UNAVAILABLE DUE TO TEST AN 9.0E-003 EPS-DGN-TM-2B DIESEL GENERATOR 2B UNAVAILABLE DUE TO TEST A 9.0E-003 EPS-XHE-XL-UNIT1 OPERATOR FAILS TO CROSS-TIE UNIT 2 EDGS TO UN 2.0E-002 EPS-XHE-XL-UNIT2 UNIT 2 EDGS UNAVAILABLE; CROSS-TIED TO UNIT 2 9.8E-001 FLAG-CCW-1A-RUNNING CCW PUMP 1A-A IS RUNNING 5.0E-001 FLAG-CCW-1B-RUNNING CCW PUMP 1B-B IS RUNNING 5.0E-001 HPI-MDP-FS-1B HPI MDP-1B FAILURE TO START 1.2E-003 HPI-MDP-TM-1B HPI MDP 1B UNAVAILABLE DUE TO TEST AND MAINTE 5.0E-003 HPR-XHE-XM OPERATOR FAILS TO INITIATE HPR 2.0E-003 2006/05/02 10:51:35 page 10
IR 05000390/2004005 IR 05000390/2004005 48 Event Name Description Curr Prob IE-CCW-CF-HXPL-AANDC CCF OF CCW HEAT EXCHANGERS A AND C PLUG 4.4E-005 IE-CCW-HTX-FOUL-HXA CCW HEAT EXCHANGER A FOULS 8.8E-004 IE-CCW-HTX-PG-HXA CCW HEAT EXCHANGER HX A PLUGS 2.6E-004 IE-CCW-MDP-FR-1AA CCW PUMP 1A-A FAILS TO RUN (INITIATING EVENT) 3.5E-002 IE-CCW-MDP-FR-1BB CCW PUMP 1B-B FAILS TO RUN (INITIATING EVENT) 3.5E-002 OEP-XHE-XL-NR02H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 2 3.7E-001 RCS-MDP-LK-BP1 RCP SEAL STAGE 1 INTEGRITY (BINDING/POPPING O 1.3E-002 RCS-MDP-LK-BP2 RCP SEAL STAGE 2 INTEGRITY (BINDING/POPPING O 2.0E-001 RHR-FAN-TM-RHRRMB RHR MDP 1B ROOM FAN UNAVAILABLE DUE TO T & M 2.0E-003 RHR-HTX-TM-HXB RHR HEAT EXCHANGER HTX-B UNAVAILABLE DUE TO T 2.5E-003 RHR-MDP-TM-1B RHR MDP 1B UNAVAILABLE DUE TO T & M 6.0E-003 SWS-MDP-FS-HB ERCW PUMP H-B FAILS TO START 1.5E-003 SWS-MDP-FS-LB FAILURE OF SWS MDP LB TO START 1.5E-003 SWS-STR-CF-ALL CCF OF SERVICE WATER STRAINERS 3.7E-006 SWS-STR-PG-A2AA SWS TRAIN 2A DISCH STRAINER A2AA FAILS 7.2E-005 SWS-STR-PG-B2BB SWS TRAIN 2B DISCH TRAINER B2BB FAILS 7.2E-005 2006/05/02 10:51:35 page 11
IR 05000390/2004005 IR 05000390/2004005 49 Appendix D Referenced E-Mails
IR 05000390/2004005 IR 05000390/2004005 50 Delivered-To: bmrowca@infosyslabs.com To:
Robert F Buell <Robert.Buell@inl.gov>,
Thomas E Wierman <Thomas.Wierman@inl.gov>,
John A Schroeder <John.Schroeder@inl.gov>
Cc:
bmrowca@islinc.com, dmr@nrc.gov
Subject:
CCW Heat Exchanger Plugging Failure Rate X-Mailer: Lotus Notes Release 6.5.1 January 21, 2004 From: Steven A Eide <Steven.Eide@inl.gov>
Date: Tue, 19 Jul 2005 16:24:12 -0600 X-MIMETrack: Serialize by Router on LNMAIL04/ENT/INEEL/US(Release 6.5.4 HF320lJune 30, 2005) at 07/19/2005 04:24:11 PM, Serialize complete at 07/19/2005 04:24:11 PM X-mxGuard-Info: Processed by sd-islinc.com using mxGuard v1.6.2 X-mxGuard-Spool-ID: 7d456c96014452de X-mxGuard-Sender: steven.eide@inl.gov X-mxGuard-Native-RelayCount: 3 X-mxGuard-Spam-Score: 3 X-mxGuard-Spam-Probability: CLEAN X-Note: This message has been scanned for spam and viruses by mxGuard for IMail (www.mxguard.com)
The existing component cooling water (CCW) template heat exchanger plugging rate of 2.5E-6/h is based on chemical industry data. I believe that this rate is too high for a clean water system such as the CCW. Because we do not have reliable data from EPIX on heat exchanger plugging, I reverted back to the following report to obtain a new rate:
Savannah River Site Generic Data Base Development (U)
WSRC-TR-93-262 C. H. Blanton and S. A. Eide Westinghouse Savannah River Company June 1993 That report recommends a heat exchanger fouling rate of 1.0E-7/h and a plugging rate of 3E-8/h (Table 6a in the report). I recommend that we use the 1.0E-7/h rate to cover fouling or plugging of CCW heat exchangers. The corresponding gamma distribution has alpha = 0.30 and beta = 3.00E+6h.
Steven A. Eide INL (208) 526-3797 From: John A Schroeder <John.Schroeder@inl.gov>
Date: Thu, 28 Jul 2005 16:28:31 -0600 X-MIMETrack: Serialize by Router on LNMAIL04/ENT/INEEL/US(Release 6.5.4 HF320lJune 30, 2005) at 07/28/2005 04:28:33 PM, Serialize complete at 07/28/2005 04:28:33 PM Content-Type: multipart/alternative; boundary="=_alternative 007B76748725704C_="
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- Bob,
IR 05000390/2004005 IR 05000390/2004005 51 The following is from our CCF expert.
John A. Schroeder Idaho National Laboratory Battelle Energy Alliance, LLC P.O. Box 1625 Idaho Falls, ID 83415-3850 Ph: 208-526-8755 FAX: 208-526-2930
Forwarded by John A Schroeder/ROE/CC01/INEEL/US on 07/28/2005 04:27 PM -----
Thomas E Wierman/WIERTE/CC01/INEEL/US 07/28/2005 03:46 PM To John A Schroeder/ROE/CC01/INEEL/US@INEL cc Subject Re: Fw: Watts Bar LOCCW Alpha 2 of 0.16 is a valid CCF HTX plugging term. It means that IF a heat exchanger plugs, there is a very good chance that its redundant HTX will plug also. Most of the plugging events have to do with environmental factors.
However, the CCF factors are based entirely on the RHR, CSS, and CSR systems. Meaning that all of these systems are cooled by service water or similar water quality. In addition, all of these heat exchangers are standby, no flow until demanded.
We have some unofficial idea that CCW HTX are not near as prone to CCF Alpha 2 approx 0.01. This may be due to the continuous flow or the lower failure rate where not as many failures are observed.
As to the modeling of 2 of 2 when 3 are installed, the acid test is whether the three are subjected to the same challenges, environment, etc. In this case it appears that the third is physically removed from the system and is not necessarily cycled in as a standby (abandoned in place). If this is the case, model the group as two, otherwise if it is only temporarily OOS the system may be modeled as three.
- Thanks, Thomas E. Wierman, Advisory Engineer Risk, Reliability, and NRC Programs Department Idaho National Laboratory P. O. Box 1625 - 3865 Idaho Falls, ID 83415 208-526-3836
IR 05000390/2004005 IR 05000390/2004005 52
IR 05000390/2004005 IR 05000390/2004005 53 Appendix E Component Cooling Water System Flow Diagram