ML050410097
| ML050410097 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 01/14/2005 |
| From: | Casto C Division of Reactor Safety II |
| To: | Archie J South Carolina Electric & Gas Co |
| References | |
| EA-05-008 IR-04-009, IR-05-006 | |
| Download: ML050410097 (26) | |
See also: IR 05000395/2005006
Text
January 14, 2005
South Carolina Electric & Gas Company
ATTN: Mr. Jeffery B. Archie
Senior Vice President, Nuclear Operations
Virgil C. Summer Nuclear Station
P. O. Box 88
Jenkinsville, SC 29065
SUBJECT:
VIRGIL C. SUMMER NUCLEAR STATION - NRC INSPECTION REPORT
05000395/2005006; PRELIMINARY WHITE FINDING
Dear Mr. Archie:
This letter and the enclosed supporting documentation discuss a finding that appears to have
low to moderate safety significance [White]. Section 4OA5.2.1.1 of NRC Inspection Report 05000395/2004009, issued on December 22, 2004, identified this finding [Unresolved Item
(URI) 05000395/2004009-01] which concerned inadequacies in your corrective actions
associated with a deficiency in the design of the emergency feedwater (EFW) system flow
control valves. This deficiency could have resulted in a common mode failure of the EFW
system as a result of plugging of the valves by tubercles and debris in the service water system.
This item was unresolved pending the NRCs determination of the safety significance.
This finding was assessed based on the best available information, including influential
assumptions, using the applicable Significance Determination Process (SDP) and was
preliminarily determined to be a White finding (i.e., a finding with some increased importance to
safety, which may require additional NRC inspection).
As indicated in the enclosed SDP Phase III Analysis, the issue appears to have a low to
moderate safety significance due to the importance of continued EFW system availability, when
supplied by the service water suction source, during events which deplete or render the
condensate storage tank inoperable. However, the risk associated with this deficiency was
somewhat mitigated by the fact that the finding only affected the alternate suction source for the
EFW system and did not impact normal EFW system operation. Additionally, other core cooling
mechanisms, such as use of the main feedwater system or primary system feed and bleed
were not affected.
This finding does not present an immediate safety concern because you instituted
compensatory measures including operator actions to install temporary hoses to bypass the
EFW flow control valves if they become plugged.
SCE&G
2
Two apparent violations (AV) of 10 CFR 50, Appendix B were identified regarding this finding.
The first, an apparent violation of Criterion III, Design Control, is identified as AV
05000395/2005006-01: EFW Flow Control Valves Are Susceptible to Plugging by
Tubercles and Other Debris from Service Water. The second, an apparent violation of Criterion
XVI, Corrective Actions, is identified as AV 05000395/2005006-02: Inadequate Corrective
Actions in Response to Potential EFW Control Valve Plugging. These apparent violations are
being considered for escalated enforcement action in accordance with the "General Statement
of Policy and Procedure for NRC Enforcement Actions (Enforcement Policy), NUREG-1600.
The current Enforcement Policy is included on the NRCs website at
http://www.nrc.gov/what-we-do/regulatory/enforcement/enforce-pol.html. Accordingly, for
administrative purposes, URI 05000395/2004009-01, is considered closed.
Before we make a final decision on this matter, we are providing you an opportunity (1) to
present to the NRC your perspectives on the facts and assumptions, used by the NRC to arrive
at the finding and its significance, at a Regulatory Conference or (2) submit your position on the
finding to the NRC in writing. If you request a Regulatory Conference, it should be held within
30 days of the receipt of this letter and we encourage you to submit supporting documentation
at least one week prior to the conference in an effort to make the conference more efficient and
effective. If a Regulatory Conference is held, it will be open for public observation and the NRC
will issue a press release to announce the conference. If you decide to submit only a written
response, such submittal should be sent to the NRC within 30 days of the receipt of this letter.
Please contact Mr. Charles R. Ogle at (404) 562-4605 within seven days of the date of this
letter to notify the NRC of your intentions regarding the regulatory conference for the
preliminary White finding. If we have not heard from you within 10 days, we will continue with
our significance determination and associated enforcement processes on this finding, and you
will be advised by separate correspondence of the results of our deliberations on this matter.
Since the NRC has not made a final determination in this matter, no Notice of Violation is being
issued for the inspection finding at this time. In addition, please be advised that the number
and characterization of the apparent violations may change as a result of further NRC review.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its
enclosure and your response (if any) will be available electronically for public inspection in the
NRC Public Document Room or from the Publicly Available Records (PARS) component of
NRCs document system (ADAMS). ADAMS is accessible from the NRC web site at
http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
SCE&G
3
If you have any questions regarding this letter, please contact me at (404) 562-4600.
Sincerely,
/RA By R. Haag For/
Charles A. Casto, Director
Division of Reactor Safety
Docket No.:
50-395
License No.:
Enclosure: SDP Phase III Analysis w/Attachments
cc w/encl.:
R. J. White
Nuclear Coordinator (Mail Code 802)
S.C. Public Service Authority
Virgil C. Summer Nuclear Station
Electronic Mail Distribution
Kathryn M. Sutton, Esq.
Winston and Strawn
Electronic Mail Distribution
Henry J. Porter, Director
Division of Radioactive Waste Mgmt.
Dept. of Health and Environmental
Control
Electronic Mail Distribution
R. Mike Gandy
Division of Radioactive Waste Mgmt.
S.C. Department of Health and
Environmental Control
Electronic Mail Distribution
Thomas D. Gatlin, General Manager
Nuclear Plant Operations (Mail Code 303)
South Carolina Electric & Gas Company
Virgil C. Summer Nuclear Station
Electronic Mail Distribution
Ronald B. Clary, Manager
Nuclear Licensing (Mail Code 830)
South Carolina Electric & Gas Company
Virgil C. Summer Nuclear Station
Electronic Mail Distribution
Distribution w/encl.:
SCE&G
4
K. Cotton, NRR
L. Slack, RII
RIDSNRRDIPMIIPB
PUBLIC
OEMail
S. Sparks, RII
- For Previous Concurrence See Attached Copy
OFFICE
RII:DRS
RII:DRS
RII:DRS
RII:DRP
RII:EICS
SIGNATURE
CRO
JHM2
KDL
CFE
NAME
COgle
JMoorman
BSchin
KLandis
CEvans
DATE
1/13/2005
1/13/2005
1/13/2005
1/13/2005
1/13/2005
E-MAIL COPY?
YES
NO YES
NO YES
NO YES
NO YES
NO YES
NO YES
NO
PUBLIC DOCUMENT
YES
NO YES
NO YES
NO YES
NO YES
NO YES
NO YES
NO
OFFICIAL RECORD COPY DOCUMENT NAME: E:\\Filenet\\ML050410097.wpd
SRA Analysis Number: SUM0403
Analysis Type: SDP Phase III
Inspection Report # : 2005006
Plant Name: V. C. Summer
Unit Number: 1
Enforcement Action #: EA-05-008
I.
Background - At V.C. Summer the Condensate Storage Tank (CST) is the normal
suction supply for the Emergency Feedwater System (standard Westinghouse design -
two motor driven and one turbine driven prime movers). Since the CST is not design to
withstand tornados, an alternate supply from the Service Water System was provided.
The piping interconnecting the two systems contains stagnant service water.
Microbiological tubercles are growing and have been growing for many years on the
inside diameter of these stagnant pipe segments.
The most flow-restricting passages in the system are in the flow control valves (IFV-
3531-EF, IFV-3541-EF, IFV-3551-EF, IFV-3536-EF, IFV-3546-EF, and IFV-3556-EF).
The flow control valves contain a cylindrical trim with several hundred orifices through
which the EFW flow to each steam generator passes. Based upon observing a spare
flow control valve trim, the orifices are widened with a countersink to about 0.125 inches
in diameter on the flow entry side and narrow to 0.049 inches in diameter on the flow
exit side. The total flow area of the orifices in a single valve trim is about 0.91 square
inches. There are no strainers in the EFW system that would prevent particles larger
than the these flow-restricting passages from entering the system. The NRC team
physically agitated samples of tubercles by rapidly shaking them in a container, to
simulate turbulent flow through an EFW pump, and found that most of the tubercle
pieces did not pulverize but instead broke into small solid pieces approximately 0.125 to
0.25 inches in diameter. The tubercle pieces were larger than the orifices and therefore
could potentially plug the orifices. The team calculated that, with an operating
differential pressure across a flow control valve of about 100 pounds per square inch,
the differential pressure across each orifice would be about 0.2 pounds. The team
found that the sample tubercle pieces were resistant to compressive forces, so that if
they became wedged into the orifices, they would likely be able to withstand much more
than 0.2 pounds of compressive forces without breaking up.
The original purchase specification for the EFW flow control valves (SP-620-044461-
000, dated October 16, 1974) had identified the process fluid as "cold condensate."
Therefore, these EFW valves had been specified for use with clean condensate water
and not for use with comparatively unclean SW which could contain silt and other debris
from the SW pond plus clam shells, tubercles, and other debris from the SW piping.
This mis-application of the purchased EFW flow control valves, which were designed for
clean condensate, to handle unclean SW in the plant represented inadequate design
control.
The licensee became aware of this potential blockage issue in 1986 and has had other
opportunities to identify the significance of this design vulnerability since that time.
Licensee corrective actions have been inadequate to resolve this design vulnerability.
Enclosure
2
Performance Deficiency - The licensees corrective actions in response to a deficiency in
the design of the EFW flow control valves was inadequate.
Specifically, the licensees design control failed to specify that the EFW flow control
valves were required to be able to handle relatively unclean SW without plugging.
Instead, the EFW flow control valves were specified to handle a process fluid of clean
cold condensate. Tubercles as well as other debris in the service water system could
plug the valves thereby resulting in a common mode failure of the EFW system.
Despite multiple opportunities, the licensees corrective action program failed to correct
the condition in a timely manner.
Exposure Time - 1 year
Date of Occurrence - Condition has existed for numerous years
II.
Safety Impact: WHITE
III.
Risk Analysis/Considerations
Assumptions
1.
Upon transfer of the Emergency Feedwater System (EFW) suction to the Service
Water System (SWS) the tubercles will plug the FCVs stopping sufficient flow to
any Steam Generator.
2.
Failure of the CST as the suction source for the Emergency Feedwater System
will cause a reactor trip during the ensuing plant shutdown. The failure of the
CST is estimated at 1E-7 failure/hour * 8760 hour0.101 days <br />2.433 hours <br />0.0145 weeks <br />0.00333 months <br />s/yr = 8.76E-4/yr. {INEEL
telecon of database search for equipment failure}
3.
For every reactor trip recovery of Main Feedwater is assumed to occur 90% of
the time. This is the estimate from the Phase 2 Screening Sheets due to plant
modifications that allow this. These modifications are not reflected in the
licensees full scope model.
4.
In the absence of the tubercles the failure of the Service Water System as a
suction for the Emergency Feedwater System is estimated at 1E-3 (a multi-train
system). Therefore, the non-conforming condition will be assumed to be the
delta CDF since the conforming case CDF is <<. (Unless specifically quantified
by computer models)
Enclosure
3
5.
Recovery of the Emergency Feedwater System, once transferred to the SWS
suction source will not be considered. The FCV cages are assumed to be
plugged to the point of insufficient flow to the Steam Generators. Operators
would be able to recognize that insufficient flow was going to the Steam
Generators.
6.
However, there would be no procedure direction, training or experience that
allow the operators to unplug the FCVs or provide a bypass around the plugged
valves. Also, there would be no equipment available to accomplish such a task.
7.
The CST function will be assumed to be lost at the medium wind speed/intensity
of a F2 tornado (135 mph). The frequency of all tornadoes of this intensity or
higher striking the site is estimated to be 6E-5/yr as extrapolated from Figure 3-2
Tornado Hazard Curve - Exceedance (page 3-6) contained in the June 1995
IPEEE High Winds Evaluation in response to Generic Letter 88-20, Supplement
4. All tornadoes assumed to cause loss of the CST function will also cause Loss
of Offsite Power without recovery.
8.
The critical piping segment from CST to EFW is estimated at 30 yards in length
with 10 welds. Failure consideration will be by Design and Construction Defects
(D&C) and Corrosion Attack (COR) mechanisms. From Table A-33, Pipe failure
Rates for Westinghouse Feedwater and Condensate Systems, of EPRI TR-
111880, Piping System Failure Rates and Rupture Frequencies for Use In Risk
Informed In-service Inspection Applications, the per foot or per weld failure
probability is:
COR = 8.47E-8 failure/yr/ft * 90 ft = 7.6E-6 failure/yr
D&C = 6.89E-7 failure/yr/weld * 10 welds = 6.89E-6 failure/yr
Total = 6.89E-6 + 7.6E-6 = 1.45E-5 failure/yr
9.
Based upon a review of the licensees safe shutdown strategy procedures
following a fire, it is assumed that when operators remain in the Main Control
Room (MCR), the train used for safe shutdown is assumed to be fully protected
either by 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> barrier, 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> barrier with suppression or a separation of 20 feet
between trains. Those procedures presently indicate that the CST would be the
suction source for the protected EFW train unless the CST was expended.
Consequently, fire effects causing actuation of the alternate EFW suction source
(SWS) could only happen to the unprotected train. For the unprotected train to
affect the protected EFW train it would require a significant number of spurious
actuations, including pump start and two suction valves to open before the
protected train would be impacted. This is screened as not credible.
Enclosure
4
Premature transfer of the protected train suction to SWS will be considered credible due
to random events and a fully developed fire in the 7.2KV Switchgear Room (Train A) will
be used as the surrogate for this situation.
Possible spurious actuation of the SWS valves to the EFW suction source caused by
the fire will be considered for those cases where alternate shutdown (shutdown from
outside the MCR) is used. The fire in the Main Control Room will be used as the
surrogate to screen this situation. Also, in all fire accident sequences it is assumed the
licensee will execute a plant shutdown to cold shutdown before the CST volume is
expended.
PRA Model used for basis of the risk analysis: Combination of hand calculation,
modified Phase 2 Screening Sheet and SPAR run in the GEM mode.
Significant Influence Factor(s) [if any]: The failure of the SWS to EFW function is always
lost when called upon and the tornado severity at which the CST function as a suction
source to EFW is lost.
IV.
Calculations
BASE CASE - N/A
NON-CONFORMING CASE
a.
Internal Events
In the non-conforming case two broad conditions will be analyzed. First the full demand
spectrum from all initiating events normally included in an internal events model will be
considered. In this case the normal EFW suction path fails upon demand. The SPAR
model is used to calculate the delta CDF by setting the basic event EFW-XHE-XA-SWS,
OPERATOR FAILS TO ALIGN SW TO EFW, to always fail (TRUE). The model
quantification details are provided in Attachment 2. Summarizing the delta CDF was
4.7E-8/yr. Due to its small contribution it will be excluded from the quantification.
Second there is a special case not explicitly covered by the internals event model that
must be included. This involves the special case where the normal EFW suction source
is known to be out of service and requires plant shutdown with an ensuing reactor trip.
The failure of the CST and the failure the piping segments from the CST to EFW pump
suctions will be quantified to estimate this initiating event. As indicated in the
assumptions section, tank failure is set at 8.76E-4 and the piping segment failure is set
at 1.45E-5. The collective loss of the CST function is estimated at 8.9E-4/yr. This
represents the Initiating Event frequency.
Enclosure
5
To acquire the CCDP portion of the CDF the SPAR model in the GEM mode was
solved for the transient initiating event with:
EFW-TNK-FC-CST1 set to TRUE - this sets the CST to always fail this will later
be substituted with the new initiating event frequency that correlates to tank loss.
EFW-XHE-XA-SWS set to TRUE - this sets the Service Water System supply to
the EFW pumps to always fail - the performance deficiency.
MFW-XHE-XL-TRANS & MFW-XHE-XL-TRIP set to 0.1 - this provides a
possible site- specific use of MFW as a viable secondary side heat removal
mechanism (consistent with assumption 3).
The details of the computer run is provided as Attachment 3. In summary the derived
CCDP was 6.2E-3. The non-conforming CDF is 8.9E-4/yr * 6.2E-3 = 5.5E-6
Correlation with the Phase 2 Screening Sheets - The Phase 2 Screening Sheet for
Transients is solved using the 8.9E-4 IEL converted to a 3 and the EFW function set to
zero. The accident sequences are shown in Attachment 4 and result in a 6,6 & 7 or
White. This is consistent with the computerized calculation.
b.
External Events
Earthquake - Based upon the licensees IPEEE (page 13-2) estimated that the High
Confidence of Low Probability of Failure (HCLPF) for the Service Water Pond Dam was
0.22g while the CST was estimated at > 0.3g. Therefore, Service Water is estimated to
fail before the CST due to earthquake and will be excluded from quantification.
Fire - Fully developed fire with operators shutting down from the MCR - Compartment
1DA is the surrogate and considered the dominant fire since there are almost 40 ignition
sources capable of causing a fully developed fire and the compartment does not contain
a fixed suppression system. A fire of 16 minutes duration will be postulated to cause
operators to enact the mitigation strategy which includes inducing a Station Blackout
and re-establishing power to the B train via the B Emergency Diesel Generator.
Therefore, MFW recovery will not be considered. From 0609, Appendix F page F8-6 the
non-suppression probability of an electrical fire is 0.15. Possible mechanisms that could
cause EFW suction transference to SWS are spurious valve operations, spurious failure
of 2 of the 4 level transmitters or tank failure. For purposes of scoping only a single
valve or level transmitter failure will be quantified at 5E-7/hr for the valve (NUREG 4550)
+ 5E-6/hr for an instrument + 1E-7/hr for tank failure over a 24 hr mission time yields
1E-4. A conservative scoping quantification would be:
The fully developed fire frequency would be 2.3E-3 (fire frequency) * 1.5E-1
(suppression failure Pr) * 1E-4 (EFW transfer to SWS) = 3E-8
Enclosure
6
Fully developed fire with operators shutting down from outside the MCR. Use the MCR
fire as the screen. From SDP Appendix F, MCR fire frequency is 8E-3. Assuming a fire
of approximately 16 minutes would be needed to cause spurious operation of the
applicable valves, the manual suppression failure probability is estimated to be 0.02
(Appendix F page F8-6).
Partitioning the MCR into the critical panel portion that could impact these valves to be
1/4 of the MCR panels would provide an addition 0.25 reduction factor. Two valves in
the train to be used for shutdown from outside the MCR would have to change state in
this critical portion of the MCR panel. Appendix F page F-48 estimates a spurious
operation of 0.6. Calculating 8E-3 * 2E-2 * 2.5E-1 * 6E-1 * 6E-1 = 1.4E-5. This would
be a fully developed fire requiring MCR evacuation with subsequent failure of the EFW
System due to transferring onto the SWS suction source. However, even though not
procedurialized there would be adequate time to establish feed & bleed as a mitigation
strategy. Using a 2E-2 failure probability as representative of this strategy failing (1E-2
for the F&B portion and 1E-2 for the HPR portion), the CDF would screen at 3E-7.
These two scoping quantifications provide the perspective that the fire initiating event
would not be a major risk contributor for this performance deficiency.
Tornado - The CST was not designed to withstand a tornado or the effects of a tornado.
Using the exceedence probability for wind speeds at an F2 median frequency as the
initiating event, yields 6E-5/yr. SPAR was run in the GEM mode with:
the LOSP initiating event for severe weather set at 6E-5
EFW-TNK-FC-CST1 set to TRUE - this sets the CST to always fail due to a
tornado
EFW-XHE-XA-SWS set to TRUE - this sets the Service Water System supply to
the EFW pumps to always fail - the performance deficiency
The non-conforming CDF result was 1.4E-6. See Attachment 5 for th details of the
computer run.
As a sensitivity analysis for tornado wind speeds in excess of 150 mph (the upper end of
the F2 scale) correlates to a 1E-6 CDF..
Correlation with the Phase 2 Screening Sheets - The surrogate for external events is
LOSP. By altering the LOOP Screening Sheet from the Phase 2 Notebook to 6E-5 for
the initiating event correlates to a 4 for the IEL, the EFW function is set to zero and the
REC functions are set to zero. The accident sequences are shown in Attachment 6 and
resulted in a 6, 6, 7 & 7 or White and consistent with the computerized calculation.
Enclosure
7
External Events Summary - The external events analysis was to ascertain whether the
White result of the internal events is altered by the external events. Evaluation of the
external events contribution indicates that the risk significance is not sufficient to
increase internal events results.
DELTA CDF FOR EXPOSURE TIME
Since the exposure time is for one year there is no alteration of the delta CDF from the
previous section.
LERF CONSIDERATION
The dominant accident sequences involving this performance deficiency do not include
SGTR or ISLOCA as the initiating event. Therefore, the LERF contribution is
considered not to exceed the CDF risk bands.
V.
Conclusions/Recommendations - Risk increase over the base case was >1E-6 but <1E-
5.
VI.
Attachments
1.
Phase I Screening Sheets
2.
Sws to efw.wpd
3.
CCDP for Loss of CST as Initiating Event
4.
Phase 2 Screening Sheet - Trans Initiating Event
5.
6.
Phase 2 Screening Sheet - LOOP Initiating Event
Analyst:
W. Rogers
Date:
12/22/04
Reviewed By:
R. Bernhard
Date: 12/22/04
M. Franovich Date: 12/29/04 per telecon
Enclosure
C O N D I T I O N A S S E S S M E N T
Code Version: 7:22 Model Version : 2004/12/10
Project : SUMM_3 Duration (hrs) : 8.8E+003
User Name : IDAHO NATIONAL LABORATORY (INL) Total CCDP : 1.4E-005
Event ID : SWS-TO-EFW-OOS Total CDP : 1.4E-005
Importance : 4.7E-008
Description : Condition Assessment sws to efw failed for one year
BASIC EVENT CHANGES
Event Name Description Base Prob Curr Prob Type
---------------------------- --------- --------- ------
EFW-XHE-XA-SWS OPERATOR FAILS TO ALIGN SW T 1.0E-003 1.0E+000 TRUE
________________________________________________________________________________
SEQUENCE PROBABILITIES
Truncation : Cummulative : 100.0% Individual : 1.0%
Event Tree Name Sequence Name CCDP CDP Importance
------------------------ --------- --------- ----------
TRANS 17 4.5E-007 4.1E-007 3.4E-008
LDCA 20 7.8E-007 7.7E-007 6.0E-009
TRANS 16 5.0E-008 4.6E-008 3.7E-009
LOOP 17 3.3E-008 3.1E-008 1.6E-009
NOTE: Percent contribution to total Importance.
SEQUENCE LOGIC
Event Tree Sequence Name Logic
------------- ---------------------------------------------------
TRANS 17 /RPS EFW
MFW FAB
LDCA 20 /RPS EFW
FAB
TRANS 16 /RPS EFW
MFW /FAB
HPR
LOOP 17 /RPS /EPS
EFW-L FAB-L
Fault Tree Name Description
------------------------------------------------------
EFW-L SUMMER PWR B EMERGENCY FEEDWATER SYSTEM DURING LOOP
2004/12/21 11:10:02 page 1
2
Attachment 2
EPS EMERGENCY POWER
FAB FEED AND BLEED
FAB-L FEED AND BLEED DURING LOOP
HPR HPR PRESSURE RECIRCULATION
________________________________________________________________________________
SEQUENCE CUT SETS
Truncation: Cummulative: 100.0% Individual: 1.0%
Event Tree: TRANS CCDF: 4.5E-007
Sequence: 17
CCDF % Cut Set Cut Set Events
--------- ----------------------------------------------------
1.6E-007 36.04 EFW-MDP-CF-FRAB EFW-TDP-FR
MFW-SYS-FC-TRIP HPI-XHE-XM-FB
4.1E-008 9.22 EFW-MDP-CF-FRAB EFW-TDP-TM
MFW-SYS-FC-TRIP HPI-XHE-XM-FB
4.0E-008 9.01 EFW-MDP-CF-FRAB EFW-TDP-FR
MFW-SYS-FC-TRANS HPI-XHE-XM-FB
3.4E-008 7.68 EFW-MDP-CF-FRAB EFW-TDP-FS-1
MFW-SYS-FC-TRIP HPI-XHE-XM-FB
2.7E-008 6.04 EFW-TNK-FC-CST1 MFW-SYS-FC-TRIP
HPI-XHE-XM-FB
2.5E-008 5.62 EFW-MDP-CF-FSAB EFW-TDP-FR
MFW-SYS-FC-TRIP HPI-XHE-XM-FB
1.0E-008 2.30 EFW-MDP-CF-FRAB EFW-TDP-TM
MFW-SYS-FC-TRANS HPI-XHE-XM-FB
8.6E-009 1.92 EFW-MDP-CF-FRAB EFW-TDP-FS-1
MFW-SYS-FC-TRANS HPI-XHE-XM-FB
7.6E-009 1.70 EFW-CKV-CF-DIS MFW-SYS-FC-TRIP
HPI-XHE-XM-FB
7.6E-009 1.70 EFW-CKV-CF-SUCT MFW-SYS-FC-TRIP
HPI-XHE-XM-FB
7.6E-009 1.70 EFW-CKV-CF-SGS MFW-SYS-FC-TRIP
HPI-XHE-XM-FB
7.4E-009 1.66 EFW-PMP-CF-ALL MFW-SYS-FC-TRIP
HPI-XHE-XM-FB
6.7E-009 1.51 EFW-TNK-FC-CST1 MFW-SYS-FC-TRANS
HPI-XHE-XM-FB
6.4E-009 1.44 EFW-MDP-CF-FSAB EFW-TDP-TM
MFW-SYS-FC-TRIP HPI-XHE-XM-FB
6.3E-009 1.40 EFW-MDP-CF-FSAB EFW-TDP-FR
MFW-SYS-FC-TRANS HPI-XHE-XM-FB
5.7E-009 1.28 EFW-MDP-CF-FRAB EFW-XHE-XR-TDP1
MFW-SYS-FC-TRIP HPI-XHE-XM-FB
5.3E-009 1.20 EFW-MDP-CF-FSAB EFW-TDP-FS-1
MFW-SYS-FC-TRIP HPI-XHE-XM-FB
2004/12/21 11:10:02 page 2
Attachment 2
3
Event Tree: LDCA CCDF: 7.8E-007
Sequence: 20
CCDF % Cut Set Cut Set Events
--------- ----------------------------------------------------
3.5E-007 45.34 EFW-MDP-TM-1B EFW-TDP-FR
7.5E-008 9.66 EFW-MDP-TM-1B EFW-TDP-FS-1
7.0E-008 9.07 EFW-TDP-FR EFW-XHE-XR-MDP1B
3.6E-008 4.62 EFW-MDP-CF-FRAB EFW-TDP-FR
2.8E-008 3.63 EFW-PMP-FR-1A EFW-TDP-FR
2.7E-008 3.50 EFW-MDP-FR-1B EFW-TDP-FR
EFW-XHE-XL-MDPFRB
1.8E-008 2.32 EFW-TDP-TM EFW-XHE-XR-MDP1B
1.8E-008 2.29 EFW-MDP-FS-1B EFW-TDP-FR
EFW-XHE-XL-MDPFSB
1.5E-008 1.93 EFW-TDP-FS-1 EFW-XHE-XR-MDP1B
1.3E-008 1.61 EFW-MDP-TM-1B EFW-XHE-XR-TDP1
1.2E-008 1.55 DCP-BDC-LP-1B
9.2E-009 1.18 EFW-MDP-CF-FRAB EFW-TDP-TM
Event Tree: TRANS CCDF: 5.0E-008
Sequence: 16
CCDF % Cut Set Cut Set Events
--------- ----------------------------------------------------
1.6E-008 32.19 HPR-XHE-XM EFW-MDP-CF-FRAB
EFW-TDP-FR MFW-SYS-FC-TRIP
4.1E-009 8.23 HPR-XHE-XM EFW-MDP-CF-FRAB
EFW-TDP-TM MFW-SYS-FC-TRIP
4.0E-009 8.05 HPR-XHE-XM EFW-MDP-CF-FRAB
EFW-TDP-FR MFW-SYS-FC-TRANS
3.4E-009 6.86 HPR-XHE-XM EFW-MDP-CF-FRAB
EFW-TDP-FS-1 MFW-SYS-FC-TRIP
2.7E-009 5.39 HPR-XHE-XM EFW-TNK-FC-CST1
MFW-SYS-FC-TRIP
2.5E-009 5.02 HPR-XHE-XM EFW-MDP-CF-FSAB
EFW-TDP-FR MFW-SYS-FC-TRIP
1.0E-009 2.06 HPR-XHE-XM EFW-MDP-CF-FRAB
EFW-TDP-TM MFW-SYS-FC-TRANS
8.6E-010 1.72 HPR-XHE-XM EFW-MDP-CF-FRAB
EFW-TDP-FS-1 MFW-SYS-FC-TRANS
7.6E-010 1.52 HPR-XHE-XM EFW-CKV-CF-SGS
MFW-SYS-FC-TRIP
7.6E-010 1.52 HPR-XHE-XM EFW-CKV-CF-DIS
MFW-SYS-FC-TRIP
7.6E-010 1.52 HPR-XHE-XM EFW-CKV-CF-SUCT
MFW-SYS-FC-TRIP
7.4E-010 1.49 HPR-XHE-XM EFW-PMP-CF-ALL
MFW-SYS-FC-TRIP
6.7E-010 1.35 HPR-XHE-XM EFW-TNK-FC-CST1
MFW-SYS-FC-TRANS
2004/12/21 11:10:02 page 3
Attachment 2
4
6.4E-010 1.28 HPR-XHE-XM EFW-MDP-CF-FSAB
EFW-TDP-TM MFW-SYS-FC-TRIP
6.3E-010 1.25 HPR-XHE-XM EFW-MDP-CF-FSAB
EFW-TDP-FR MFW-SYS-FC-TRANS
5.7E-010 1.14 HPR-XHE-XM EFW-MDP-CF-FRAB
EFW-XHE-XR-TDP1 MFW-SYS-FC-TRIP
5.3E-010 1.07 HPR-XHE-XM EFW-MDP-CF-FSAB
EFW-TDP-FS-1 MFW-SYS-FC-TRIP
Event Tree: LOOP CCDF: 3.3E-008
Sequence: 17
CCDF % Cut Set Cut Set Events
--------- ----------------------------------------------------
9.5E-009 29.09 EFW-MDP-CF-FRAB EFW-TDP-FR
HPI-XHE-XM-FB
2.4E-009 7.44 EFW-MDP-CF-FRAB EFW-TDP-TM
HPI-XHE-XM-FB
2.0E-009 6.20 EFW-MDP-CF-FRAB EFW-TDP-FS-1
HPI-XHE-XM-FB
2.0E-009 6.05 EFW-MDP-TM-1B EFW-TDP-FR
EPS-DGN-FR-1A HPI-XHE-XM-FB
2.0E-009 6.05 EFW-MDP-TM-1A EFW-TDP-FR
EPS-DGN-FR-1B HPI-XHE-XM-FB
1.6E-009 4.87 EFW-TNK-FC-CST1 HPI-XHE-XM-FB
1.5E-009 4.53 EFW-MDP-CF-FSAB EFW-TDP-FR
HPI-XHE-XM-FB
4.5E-010 1.37 EFW-CKV-CF-SUCT HPI-XHE-XM-FB
4.5E-010 1.37 EFW-CKV-CF-DIS HPI-XHE-XM-FB
4.5E-010 1.37 EFW-CKV-CF-SGS HPI-XHE-XM-FB
4.4E-010 1.34 EFW-PMP-CF-ALL HPI-XHE-XM-FB
4.2E-010 1.29 EFW-MDP-TM-1B EFW-TDP-FS-1
EPS-DGN-FR-1A HPI-XHE-XM-FB
4.2E-010 1.29 EFW-MDP-TM-1A EFW-TDP-FS-1
EPS-DGN-FR-1B HPI-XHE-XM-FB
4.0E-010 1.21 EFW-TDP-FR EFW-XHE-XR-MDP1B
EPS-DGN-FR-1A HPI-XHE-XM-FB
4.0E-010 1.21 EFW-TDP-FR EFW-XHE-XR-MDP1A
EPS-DGN-FR-1B HPI-XHE-XM-FB
3.8E-010 1.16 EFW-MDP-CF-FSAB EFW-TDP-TM
HPI-XHE-XM-FB
3.7E-010 1.14 EFW-MDP-TM-1B EFW-TDP-FR
EPS-DGN-FS-1A HPI-XHE-XM-FB
3.7E-010 1.14 EFW-MDP-TM-1A EFW-TDP-FR
EPS-DGN-FS-1B HPI-XHE-XM-FB
3.4E-010 1.03 EFW-MDP-CF-FRAB EFW-XHE-XR-TDP1
HPI-XHE-XM-FB
________________________________________________________________________________
2004/12/21 11:10:02 page 4
Attachment 2
5
BASIC EVENTS (Cut Sets Only)
Event Name Description Curr Prob
--------------------------------------------- ---------
DCP-BDC-LP-1B DIVISION 1B 125VDC BUS DP-1B ED FAILS 4.8E-006
EFW-CKV-CF-DIS COMMON CAUSE FAILURE OF EFW PUMPS DISCHARGE C 6.8E-007
EFW-CKV-CF-SGS COMMON CAUSE FAILURE OF SGS EFW CHECK VALVES 6.8E-007
EFW-CKV-CF-SUCT COMMON CAUSE FAILURE OF EFW PUMPS SUCTION CHE 6.8E-007
EFW-MDP-CF-FRAB CCF FAILURE OF EFW MDPS TO RUN 5.1E-004
EFW-MDP-CF-FSAB CCF EFW MDP FAIL TO START 7.9E-005
EFW-MDP-FR-1B EFW MDP 1B FAILS TO RUN 5.2E-004
EFW-MDP-FS-1B EFW MDP 1B FAILS TO START 1.2E-003
EFW-MDP-TM-1A EFW MDP 1A UNAVAILABLE DUE TO TEST AND MAINTE 5.0E-003
EFW-MDP-TM-1B EFW MDP 1B UNAVAILABLE DUE TO TEST AND MAINTE 5.0E-003
EFW-PMP-CF-ALL COMMON CAUSE FAILURE OF EFW PUMPS 6.6E-007
EFW-PMP-FR-1A FAILURE OF EFW PUMP 1A TO RUN (PUMP UNIT ONLY 4.0E-004
EFW-TDP-FR EFW TDP FAILS TO RUN 2.8E-002
EFW-TDP-FS-1 EFW TDP FAILS TO START 6.0E-003
EFW-TDP-TM EFW TDP UNAVAILABLE DUE TO TEST AND MAINTENAN 7.2E-003
EFW-TNK-FC-CST1 FAILURE OF CONDENSATE STORAGE TANK 2.4E-006
EFW-XHE-XL-MDPFRB OPERATOR FAILS TO RECOVER EFW MDP 1B (FAILS T 7.5E-001
EFW-XHE-XL-MDPFSB OPERATOR FAILS TO RECOVER EFW MDP 1B (FAILS T 2.1E-001
EFW-XHE-XR-MDP1A OP FAILS TO RESTORE EFW MDP 1A AFTER T&M 1.0E-003
EFW-XHE-XR-MDP1B OP FAILS TO RESTORE EFW MDP 1B 1.0E-003
EFW-XHE-XR-TDP1 OP FAILS TO RESTORE EFW TDP AFTER T&M 1.0E-003
EPS-DGN-FR-1A DIESEL GENERATOR A FAILS TO RUN 2.1E-002
EPS-DGN-FR-1B DIESEL GENERATOR B FAILS TO RUN 2.1E-002
EPS-DGN-FS-1A DIESEL GENERATOR A FAILS TO START 4.0E-003
EPS-DGN-FS-1B DIESEL GENERATOR B FAILS TO START 4.0E-003
HPI-XHE-XM-FB OPERATOR FAILS TO INITIATE FEED AND BLEED COO 2.0E-002
HPR-XHE-XM OPERTATOR FAILS TO INITIATE HPR 2.0E-003
MFW-SYS-FC-TRANS MFW IS UNAVAILABLE (TRANSIENT INTIATOR) 2.0E-001
MFW-SYS-FC-TRIP MFW IS UNAVAILABLE (TRANSIENT INTIATOR) 8.0E-001
2004/12/21 11:10:02 page 5
Attachment 2
CCDP FOR LOSS OF CST FUNCTION AS THE INITIATING EVENT
I N I T I A T I N G E V E N T A S S E S S M E N T
Code Ver : 7:22
Fam : SUMM_3 Model Ver : 2004/12/10
User : IDAHO NATIONAL LABORATORY (INL) Init Event: IE-TRANS
Ev ID: TRANS-W-O-CST--SWAFW Total CCDP: 6.2E-003
Desc : Initiating Event Assessment
BASIC EVENT CHANGES
Event Name Description Base Prob Curr Prob Type
---------------------------- --------- --------- ------
EFW-TNK-FC-CST1 FAILURE OF CONDENSATE STORAG 2.4E-006 1.0E+000 TRUE
EFW-XHE-XA-SWS OPERATOR FAILS TO ALIGN SW T 1.0E-003 1.0E+000 TRUE
IE-LDCA LOSS OF DC POWER BUS 1A INIT 2.5E-003 +0.0E+000
IE-LLOCA LARGE LOSS OF COOLANT ACCIDE 5.0E-006 +0.0E+000
IE-LOCCW LOSS OF COMPONENT COOLING WA 2.0E-004 +0.0E+000
IE-LOOP LOSS OF OFFSITE POWER 3.3E-002 +0.0E+000
IE-LOSW LOSS OF SERVICE WATER INITIA 4.0E-004 +0.0E+000
IE-MLOCA MEDIUM LOSS OF COOLANT ACCID 4.0E-005 +0.0E+000
IE-RHR-CLDIS-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-RHR-HLDIS-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-RHR-SUC-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-SGTR STEAM GENERATOR TUBE RUPTURE 4.0E-003 +0.0E+000
IE-SI-CLDIS-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-SI-HLDIS-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-SLOCA SMALL LOSS OF COOLANT ACCIDE 4.0E-004 +0.0E+000
IE-TRANS TRANSIENT 7.0E-001 1.0E+000
MFW-XHE-XL-TRANS OPERATOR FAILS TO RECOVER MF 1.0E+000 1.0E-001
MFW-XHE-XL-TRIP OPERATOR FAILS TO RECOVER MF 1.0E+000 1.0E-001
________________________________________________________________________________
SEQUENCE PROBABILITIES
Truncation : Cummulative : 100.0% Individual : 1.0%
Event Tree Name Sequence Name CCDP %Cont
------------------------ --------- -----
TRANS 17 5.9E-003
TRANS 16 2.3E-004
SEQUENCE LOGIC
Event Tree Sequence Name Logic
------------- ---------------------------------------------------
TRANS 17 /RPS EFW
MFW FAB
TRANS 16 /RPS EFW
MFW /FAB
HPR
2004/12/21 10:06:37 page 1
Attachment 3
2
Fault Tree Name Description
------------------------------------------------------
FAB FEED AND BLEED
HPR HPR PRESSURE RECIRCULATION
________________________________________________________________________________
SEQUENCE CUT SETS
Truncation: Cummulative: 100.0% Individual: 1.0%
Event Tree: TRANS CCDP: 5.9E-003
Sequence: 17
CCDP % Cut Set Cut Set Events
--------- ----------------------------------------------------
5.5E-003 92.92 MFW-SYS-FC-TRIP MFW-XHE-XL-TRIP
HPI-XHE-XM-FB1
4.0E-004 6.73 MFW-SYS-FC-TRANS MFW-XHE-XL-TRANS
HPI-XHE-XM-FB
Event Tree: TRANS CCDP: 2.3E-004
Sequence: 16
CCDP % Cut Set Cut Set Events
--------- ----------------------------------------------------
1.6E-004 71.03 HPR-XHE-XM MFW-SYS-FC-TRIP
MFW-XHE-XL-TRIP
4.0E-005 17.76 HPR-XHE-XM MFW-SYS-FC-TRANS
MFW-XHE-XL-TRANS
4.3E-006 1.92 MFW-SYS-FC-TRIP MFW-XHE-XL-TRIP
RHR-MDP-CF-FSAB
________________________________________________________________________________
BASIC EVENTS (Cut Sets Only)
Event Name Description Curr Prob
--------------------------------------------- ---------
HPI-XHE-XM-FB OPERATOR FAILS TO INITIATE FEED AND BLEED COO 2.0E-002
HPI-XHE-XM-FB1 OPERATOR FAILS TO INITIATE FEED AND BLEED COO 6.9E-002
HPR-XHE-XM OPERTATOR FAILS TO INITIATE HPR 2.0E-003
MFW-SYS-FC-TRANS MFW IS UNAVAILABLE (TRANSIENT INTIATOR) 2.0E-001
MFW-SYS-FC-TRIP MFW IS UNAVAILABLE (TRANSIENT INTIATOR) 8.0E-001
MFW-XHE-XL-TRANS OPERATOR FAILS TO RECOVER MFW (TRANSIENT INIT 1.0E-001
MFW-XHE-XL-TRIP OPERATOR FAILS TO RECOVER MFW (TRANSIENT INIT 1.0E-001
RHR-MDP-CF-FSAB COMMON CAUSE FAILURE OF RHR MDPS TO START 5.4E-005
2004/12/21 10:06:37 page 2
Attachment 3
Attachment 5
I N I T I A T I N G E V E N T A S S E S S M E N T
Code Ver : 7:22
Fam : SUMM_3 Model Ver : 2004/12/10
User : IDAHO NATIONAL LABORATORY (INL) Init Event: IE-LOOP
Ev ID: LOOP-SEVERE-TEST Total CCDP: 1.4E-006
Desc : Initiating Event Assessment
BASIC EVENT CHANGES
Event Name Description Base Prob Curr Prob Type
---------------------------- --------- --------- ------
EFW-TNK-FC-CST1 FAILURE OF CONDENSATE STORAG 2.4E-006 1.0E+000 TRUE
EFW-XHE-XA-SWS OPERATOR FAILS TO ALIGN SW T 1.0E-003 1.0E+000 TRUE
IE-LDCA LOSS OF DC POWER BUS 1A INIT 2.5E-003 +0.0E+000
IE-LLOCA LARGE LOSS OF COOLANT ACCIDE 5.0E-006 +0.0E+000
IE-LOCCW LOSS OF COMPONENT COOLING WA 2.0E-004 +0.0E+000
IE-LOOP LOSS OF OFFSITE POWER 3.3E-002 6.0E-005
IE-LOSW LOSS OF SERVICE WATER INITIA 4.0E-004 +0.0E+000
IE-MLOCA MEDIUM LOSS OF COOLANT ACCID 4.0E-005 +0.0E+000
IE-RHR-CLDIS-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-RHR-HLDIS-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-RHR-SUC-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-SGTR STEAM GENERATOR TUBE RUPTURE 4.0E-003 +0.0E+000
IE-SI-CLDIS-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-SI-HLDIS-V ISLOCA OCCURS WITH REACTOR A 1.0E+000 +0.0E+000
IE-SLOCA SMALL LOSS OF COOLANT ACCIDE 4.0E-004 +0.0E+000
IE-TRANS TRANSIENT 7.0E-001 +0.0E+000
OEP-XHE-XL-NR01H OPERATOR FAILS TO RECOVER OF 5.3E-001 4.6E-001
OEP-XHE-XL-NR02H OPERATOR FAILS TO RECOVER OF 3.7E-001 3.6E-001
OEP-XHE-XL-NR03H OPERATOR FAILS TO RECOVER OF 2.8E-001 3.0E-001
OEP-XHE-XL-NR04H OPERATOR FAILS TO RECOVER OF 2.2E-001 2.5E-001
OEP-XHE-XL-NR05H OPERATOR FAILS TO RECOVER OF 1.9E-001 2.2E-001
OEP-XHE-XL-NR06H OPERATOR FAILS TO RECOVER OF 1.6E-001 2.0E-001
OEP-XHE-XL-NR07H OPERATOR FAILS TO RECOVER OF 1.4E-001 1.8E-001
OEP-XHE-XL-NR08H OPERATOR FAILS TO RECOVER OF 1.2E-001 1.6E-001
OEP-XHE-XL-NR09H OPERATOR FAILS TO RECOVER OF 1.1E-001 1.4E-001
OEP-XHE-XL-NR10H OPERATOR FAILS TO RECOVER OF 1.0E-001 1.3E-001
OEP-XHE-XL-NR10H2 OPERATOR FAILS TO RECOVER OF 2.7E-001 3.7E-001
OEP-XHE-XL-NR10H4 OPERATOR FAILS TO RECOVER OF 4.5E-001 5.2E-001
OEP-XHE-XL-NR11H OPERATOR FAILS TO RECOVER OF 9.5E-002 1.2E-001
OEP-XHE-XL-NR12H OPERATOR FAILS TO RECOVER OF 8.9E-002 1.1E-001
OEP-XHE-XL-NR13H OPERATOR FAILS TO RECOVER OF 8.5E-002 1.0E-001
OEP-XHE-XL-NR14H OPERATOR FAILS TO RECOVER OF 8.2E-002 9.7E-002
OEP-XHE-XL-NR15H OPERATOR FAILS TO RECOVER OF 7.9E-002 9.0E-002
OEP-XHE-XL-NR16H OPERATOR FAILS TO RECOVER OF 7.6E-002 8.4E-002
OEP-XHE-XL-NR17H OPERATOR FAILS TO RECOVER OF 7.4E-002 7.9E-002
OEP-XHE-XL-NR18H OPERATOR FAILS TO RECOVER OF 7.2E-002 7.4E-002
OEP-XHE-XL-NR19H OPERATOR FAILS TO RECOVER OF 7.1E-002 7.0E-002
OEP-XHE-XL-NR20H OPERATOR FAILS TO RECOVER OF 6.9E-002 6.6E-002
OEP-XHE-XL-NR21H OPERATOR FAILS TO RECOVER OF 6.8E-002 6.2E-002
OEP-XHE-XL-NR22H OPERATOR FAILS TO RECOVER OF 6.7E-002 5.9E-002
2004/12/21 16:57:15 page 1
2
Attachment 5
OEP-XHE-XL-NR23H OPERATOR FAILS TO RECOVER OF 6.6E-002 5.6E-002
OEP-XHE-XL-NR24H OPERATOR FAILS TO RECOVER OF 6.5E-002 5.3E-002
OEP-XHE-XL-NR30M OPERATOR FAILS TO RECOVER OF 6.6E-001 5.6E-001
OEP-XHE-XL-NR90M OPERATOR FAILS TO RECOVER OF 4.4E-001 4.0E-001
ZV-LOOP-EW-LAMBDA EXTREME WEATHER RELATED LOSS 2.3E-003 +0.0E+000
ZV-LOOP-GR-LAMBDA GRID RELATED LOSS OF OFFSITE 1.7E-002 +0.0E+000
ZV-LOOP-PC-LAMBDA PLANT CENTERED LOSS OF OFFSI 2.4E-003 +0.0E+000
ZV-LOOP-SC-LAMBDA SWITCHYARD CENTERED LOSS OF 8.7E-003 +0.0E+000
ZV-LOOP-SW-LAMBDA SEVERE WEATHER RELATED LOSS 3.0E-003 1.0E+000
SEQUENCE PROBABILITIES
Truncation : Cummulative : 100.0% Individual : 1.0%
Event Tree Name Sequence Name CCDP %Cont
------------------------ --------- -----
LOOP 17 1.2E-006
LOOP 14 1.1E-007
LOOP 18-45 4.3E-008
LOOP 16 3.8E-008
SEQUENCE LOGIC
Event Tree Sequence Name Logic
------------- ---------------------------------------------------
LOOP 17 /RPS /EPS
EFW-L FAB-L
LOOP 14 /RPS /EPS
EFW-L /FAB-L
/OPR-06H HPR
EFW-B OPR-01H
DGR-01H
LOOP 16 /RPS /EPS
EFW-L /FAB-L
OPR-06H HPR-L
Fault Tree Name Description
------------------------------------------------------
DGR-01H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 1 HOUR
EFW-B SUMMER PWR B EMERGENCY FEEDWATER SYSTEM DURING SBO
EFW-L SUMMER PWR B EMERGENCY FEEDWATER SYSTEM DURING LOOP
EPS EMERGENCY POWER
FAB-L FEED AND BLEED DURING LOOP
HPR HIGH PRESSURE RECIRC
HPR-L HIGH PRESSURE RECIRC
OPR-01H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 1 HOUR
2004/12/21 16:57:15 page 2
3
Attachment 5
OPR-06H OFFSITE POWER RECOVERY IN 6 HRS
RPS REACTOR SHUTDOWN
________________________________________________________________________________
SEQUENCE CUT SETS
Truncation: Cummulative: 100.0% Individual: 1.0%
Event Tree: LOOP CCDP: 1.2E-006
Sequence: 17
CCDP % Cut Set Cut Set Events
--------- ----------------------------------------------------
1.2E-006 98.00 HPI-XHE-XM-FB
Event Tree: LOOP CCDP: 1.1E-007
Sequence: 14
CCDP % Cut Set Cut Set Events
--------- ----------------------------------------------------
9.7E-008 89.00 HPR-XHE-XM /OEP-XHE-XL-NR06H
2.6E-009 2.41 /OEP-XHE-XL-NR06H RHR-MDP-CF-FSAB
Event Tree: LOOP CCDP: 4.3E-008
Sequence: 18-45
CCDP % Cut Set Cut Set Events
--------- ----------------------------------------------------
1.4E-008 32.02 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-DGN-CF-FRAB
1.1E-008 24.48 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-DGN-FR-1A EPS-DGN-FR-1B
4.5E-009 10.41 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-DGN-TM-1A EPS-DGN-FR-1B
4.5E-009 10.41 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-DGN-TM-1B EPS-DGN-FR-1A
2.0E-009 4.62 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-DGN-FS-1A EPS-DGN-FR-1B
2.0E-009 4.62 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-DGN-FS-1B EPS-DGN-FR-1A
2.0E-009 4.57 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-DGN-CF-FSAB
8.4E-010 1.97 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-DGN-TM-1B EPS-DGN-FS-1A
8.4E-010 1.97 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-DGN-TM-1A EPS-DGN-FS-1B
5.0E-010 1.16 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-XHE-XR-DGN1A EPS-DGN-FR-1B
5.0E-010 1.16 EPS-XHE-XL-NR01H OEP-XHE-XL-NR01H
EPS-XHE-XR-DGN1B EPS-DGN-FR-1A
2004/12/21 16:57:15 page 3
4
Attachment 5
Event Tree: LOOP CCDP: 3.8E-008
Sequence: 16
CCDP % Cut Set Cut Set Events
--------- ----------------------------------------------------
2.3E-008 61.34 HPR-XHE-XM OEP-XHE-XL-NR06H
1.5E-009 3.90 OEP-XHE-XL-NR06H EPS-DGN-FR-1A
RHR-MDP-TM-1B
1.5E-009 3.90 OEP-XHE-XL-NR06H EPS-DGN-FR-1B
RHR-MDP-TM-1A
6.3E-010 1.66 OEP-XHE-XL-NR06H RHR-MDP-CF-FSAB
6.2E-010 1.62 OEP-XHE-XL-NR06H EPS-DGN-FR-1A
CCW-HTX-TM-1B
________________________________________________________________________________
BASIC EVENTS (Cut Sets Only)
Event Name Description Curr Prob
--------------------------------------------- ---------
CCW-HTX-TM-1B CCW HTX 1B UNAVAILABLE DUE TO T&M 2.5E-003
EPS-DGN-CF-FRAB DIESEL GENERATOR COMMON CAUSE FAILS TO RUN 5.9E-004
EPS-DGN-CF-FSAB DIESEL GENERATOR COMMON CAUSE FAILS TO START 8.4E-005
EPS-DGN-FR-1A DIESEL GENERATOR A FAILS TO RUN 2.1E-002
EPS-DGN-FR-1B DIESEL GENERATOR B FAILS TO RUN 2.1E-002
EPS-DGN-FS-1A DIESEL GENERATOR A FAILS TO START 4.0E-003
EPS-DGN-FS-1B DIESEL GENERATOR B FAILS TO START 4.0E-003
EPS-DGN-TM-1A DIESEL GENERATOR 1A UNAVAILABLE DUE TO T&M 9.0E-003
EPS-DGN-TM-1B DIESEL GENERATOR 1B UNAVAILABLE DUE TO T&M 9.0E-003
EPS-XHE-XL-NR01H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 8.4E-001
EPS-XHE-XR-DGN1A OPERATOR FAILS TO RESTORE DIESEL GENERATOR A 1.0E-003
EPS-XHE-XR-DGN1B OPERATOR FAILS TO RESTORE DIESEL GENERATOR B 1.0E-003
HPI-XHE-XM-FB OPERATOR FAILS TO INITIATE FEED AND BLEED COO 2.0E-002
HPR-XHE-XM OPERTATOR FAILS TO INITIATE HPR 2.0E-003
OEP-XHE-XL-NR01H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 1 4.6E-001
OEP-XHE-XL-NR06H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 6 2.0E-001
RHR-MDP-CF-FSAB COMMON CAUSE FAILURE OF RHR MDPS TO START 5.4E-005
RHR-MDP-TM-1A RHR MDP 1A UNAVAILABLE DUE TO TEST AND MAINTE 6.0E-003
RHR-MDP-TM-1B RHR MDP 1B UNAVAILABLE DUE TO TEST AND MAINTE 6.0E-003
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