ML050260525
| ML050260525 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 01/24/2005 |
| From: | Chamberlain D Division of Reactor Safety IV |
| To: | Sheppard J South Texas |
| References | |
| Download: ML050260525 (45) | |
Text
January 24, 2005 James J. Sheppard, President and Chief Executive Officer STP Nuclear Operating Company P.O. Box 289 Wadsworth, TX 77483
SUBJECT:
SUMMARY
OF SOUTH TEXAS PROJECT RISK-INFORMED TECHNICAL SPECIFICATIONS PUBLIC MEETING
Dear Mr. Sheppard:
This refers to the public meeting conducted at Arlington, Texas, on January 18, 2005, between the NRC and your staff. The participants discussed issues related to a risk-informed technical specification initiative at South Texas Project.
The attendance list is enclosed with this summary (Enclosure 1). Presentation slides from the NRC (Enclosure 2) and South Texas Project (Enclosure 3) are also attached.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosures 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).
Sincerely,
/RA/
Dwight D. Chamberlain, Director Division of Reactor Safety Dockets: 50-498; 50-499 Licenses: NPF-76; NPF-80
Enclosure:
- 1. Attendance List
- 2. NRC Presentation Slides
- 3. STP Presentation Slides
STP Nuclear Operating Company cc w/enclosures:
Tom Jordan, Vice President Engineering & Technical Services STP Nuclear Operating Company P.O. Box 289 Wadsworth, TX 77483 S. M. Head, Manager, Licensing STP Nuclear Operating Company P.O. Box 289, Mail Code: N5014 Wadsworth, TX 77483 C. Kirksey/C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 J. J. Nesrsta/R. K. Temple City Public Service Board P.O. Box 1771 San Antonio, TX 78296 D. G. Tees/R. L. Balcom Texas Genco, LP P.O. Box 1700 Houston, TX 77251 Jon C. Wood Cox Smith Matthews 112 E. Pecan, Suite 1800 San Antonio, TX 78205 A. H. Gutterman, Esq.
Morgan, Lewis & Bockius 1111 Pennsylvania Avenue NW Washington, DC 20004 C. A. Johnson/R. P. Powers AEP Texas Central Company P.O. Box 289, Mail Code: N5022 Wadsworth, TX 77483 INPO Records Center 700 Galleria Parkway Atlanta, GA 30339
STP Nuclear Operating Company Director, Division of Compliance & Inspection Bureau of Radiation Control Texas Department of State Health Services 1100 West 49th Street Austin, TX 78756 Brian Almon Public Utility Commission William B. Travis Building P.O. Box 13326 1701 North Congress Avenue Austin, TX 78701-3326 Environmental and Natural Resources Policy Director P.O. Box 12428 Austin, TX 78711-3189 Judge, Matagorda County Matagorda County Courthouse 1700 Seventh Street Bay City, TX 77414 Terry Parks, Chief Inspector Texas Department of Licensing and Regulation Boiler Program P.O. Box 12157 Austin, TX 78711 Susan M. Jablonski Office of Permitting, Remediation and Registration Texas Commission on Environmental Quality MC-122, P.O. Box 13087 Austin, TX 78711-3087 Ted Enos 4200 South Hulen Suite 630 Fort Worth, TX 76109
STP Nuclear Operating Company Electronic distribution by RIV:
Regional Administrator (BSM1)
DRP Director (ATH)
DRS Director (DDC)
DRS Deputy Director (vacant)
Senior Resident Inspector (JXC2)
Branch Chief, DRP/A (WDJ)
Senior Project Engineer, DRP/A (TRF)
Team Leader, DRP/TSS (RLN1)
RITS Coordinator (KEG)
SISP Review Completed: Yes______
ADAMS: : Yes G No Initials:
MFR______
- Publicly Available G Non-Publicly Available G Sensitive
- Non-Sensitive SRA D:DRS MFRunyan/lmb DDChamberlain
/RA/
/RA/
1/24/05 1/24/05
STP Nuclear Operating Company OFFICIAL RECORD COPY T=Telephone E=E-mail F=Fax Attendance List South Texas Project J. Phelps, Unit 2 Operations Manager S. Head, Manger, Licensing R. Grantom, Manager, Risk Management W. Harrison, Senior Staff Licensing Engineer D. Richards, Lead Engineer, Risk Management NRC D. Chamberlain, Director, Division of Reactor Safety M. Shaffer, Acting Deputy Director, Division of Reactor Safety T. Vegel, Deputy Director, Division of Reactor Safety T. Farnholtz, Senior Project Engineer R. Bywater, Senior Reactor Analyst D. Loveless, Senior Reactor Analyst M. Runyan, Senior Reactor Analyst R. Tjader, Office of Nuclear Reactor Regulation T. Boyce, Office of Nuclear Reactor Regulation S. Alexander, Office of Nuclear Reactor Regulation NRC Presentation Slides
1 Risk Management Technical Specifications (RMTS)
Initiative 4b Risk Informed Completion Times Presentation to the NRC Region IV Staff January 18, 2005
2 Presentation Participants Bob Tjader, NRR TS Section Tom Boyce, NRR TS Section Stephen Alexander, NRR MR Section
3 Development
- Standard Technical Specifications - 1974
- NUREG-1024, Technical Specifications, Enhancing the Safety Impact - 1983
- Interim Tech Spec Policy Statement - 1987
- Improved Standard Technical Specifications -
1992
- PRA Policy Statement - 1995
- Implementation of 50.65(a)(4) - 2000
- Risk Management Technical Specifications (RMTS) Initiatives - 1998 to Present
4 Principles for RMTS Development
- Achieve coherence with other risk-informed regulation development (MRule, 50.69, PRA Quality): Focus on Safety
- Credit for 50.65(a)(4) programs in RMTS Initiatives
- Licensees risk programs/PRA models must meet standards for quality & comprehensiveness
- Involve NRC staff with cognizance for operation, training, inspection, maintenance, regions/STA, and risk assessment
5 STATUS OF INITIATIVES
- Reliance on existing (a)(4) Program
- Initiative 2: Missed Surveillances (NRC Approved)
- Initiative 3: Mode Change Flexibility (NRC Approved)
- Analysis of Specific Plant Configurations
- Initiative 1: Modified End States (1-2 yrs)
- Initiative 6: LCO 3.0.3 Action Times (1-2 yrs)
- Initiative 7: Non-TS Support System Operability (1 yr)
- Quantitative Risk Assessment
- Initiative 4: Flexible Completion Times (1-3 yrs)
- Initiative 5: Surveillance Frequency Program (1-3 yrs)
- Rulemaking
- Initiative 8: Relocate non-risk significant systems from TS (3+yrs)
6 Initiative 4 - Risk-Informed Completion Times
- Effect: Extend completion time from a nominal value up to a predetermined backstop maximum using configuration risk management.
Description:
Submittal to include: approved decision-making process; implementation guidance; requirements for PRA technical adequacy; quantitative configuration &
cumulative risk metrics, including criteria for shutdown.
- Status: Industry submitted draft guidance document &
pilot proposals; staff provided feedback. Pilot plants are STP, Hope Creek, Prairie Island, & Fort Calhoun (CE TSTF-424 pilot).
7 RMTS INITIATIVE 4b and PRA QUALITY
- Use of plant configuration risk results to determine Completion Times in near real-time is a significant change to Technical Specifications
- Licensees use of PRA
- NRC Review & Oversight
- PRA must be of adequate quality for the application
- Configuration Risk Management process must be able to reliably assess risk
- Reliance on CRM tool requires licensee QC and NRC review
8 PRA QUALITY MUST BE ADEQUATE TO SUPPORT I4b
- Quality is defined in terms of scope (initiating events, plant operating modes), level of detail, and technical adequacy
- Staff will need to perform PRA reviews for external events, transition and shutdown modes
- Current thinking is that the I4b scope should include internal & external initiating events, and transition & shutdown risk
9 Initiative 4b Example
- See proposed 4b Tech Spec; discuss concepts
- Initiative 4b concepts
- Front Stop; current CT
- CRMP-based CT
- Back Stop
- Risk Assessment Tools provide reliable results in a timely manner
- Use of reliable Decision Making Process
10
11 POTENTIAL IMPLEMENTATION STRUCTURE
- Program Requirements in Technical Specifications Administrative Controls
- Guidance Documents (RG 1.177+, RMG)
- Licensee Program Guidance
- Oversight
12 Pilot Plant General Acceptance Criteria
- Exportability;
- Reliability
- Repeatability
- Enforceable/Oversight
13 REVIEW ISSUES
- PRA Quality (proof of concept)
- Scope
- Level of Detail
- Technical Acceptability
- Criteria for temporary risk increments (planned maintenance vs emergent conditions)
- Control/assessment of cumulative risk
- Credit for contingency actions & comp measures
- Uncertainty and impact on CTs/AOTs
- Configuration Risk Monitors and Assessment Tools
- Extent of PRA Incorporation
- QA/QC of software & updates
14 Backup Slides
15 Pilots for PRA Quality
16 PRA QUALITY MUST BE ADEQUATE TO SUPPORT I4b (contd)
- For internal events PRA:
- Use ASME standard & RG 1.200
- Establish a basis for PRA technical adequacy that is sufficient to meet adequacy requirements (e.g., ASME capability cat 2)
- Use PRA model peer review findings & observations
- Use results of self assessment process to identify areas where PRA does not meet the prescribed basis (ASME Capability Category 2)
- Assess the impact of those ASME Supporting Requirements that are met on I4b process; upgrade PRA
- For external events, internal fires, transient & shutdown risk staff will need to perform reviews of licensees PRA
- Account for application specific key sources of uncertainty (e.g., PRA assumptions)
STP Presentation Slides
STP Risk-Informed Technical Specifications Application NRC Region IV January 18, 2005
2 Introduction
- STP Participants
- Jay Phelps Operations Manager, Unit 2
- Scott Head Manager, Licensing
- Rick Grantom Manager, Risk Management
- Drew Richards Lead Engineer, Risk Management Applications &
Development
- Wayne Harrison Sr. Staff Licensing Engineer
3 Agenda
- Submittal schedule
- Overview of the STP application
- Implementation
4 Submittal Schedule
- Submitted Letter of Intent with proposed changes in March 2003
- License Amendment Request submitted in August 2004
- Final approval in 2005
5 Overview
- Industry pilot for risk-informed Technical Specifications using configuration risk management
- Applies STPs Maintenance Rule (a)(4) approach to determine configuration based allowed outage times.
- Will apply the industry Risk Managed Technical Specifications Guide
6 Overview (cont.)
- Current Technical Specification structure and format retained
- Allows operators to use risk management option to determine allowed outage time when the existing allowed outage time or frontstop time is exceeded
- Imposes a backstop time to return inoperable equipment to service
7 Overview - TS 3.13.1 3/4.13 RISK MANAGEMENT 3/4.13.1 ALLOWED OUTAGE TIME DETERMINATIONS LIMITING CONDITION FOR OPERATION 3.13.1 When referred to this specification, equipment that has been declared inoperable shall be evaluated for its impact on plant risk and allowed outage times determined accordingly.
APPLICABILITY:
As required by the referencing specification(s)
ACTION:
Determine that the configuration is acceptable for extension of the allowed outage time beyond the allowed outage time for the referencing specification(s),
AND Determine that the configuration is acceptable for continued operation beyond the allowed outage time for the referencing specification(s) whenever configuration changes occur that may affect plant risk, AND Restore required inoperable subsystem, component to OPERABLE status within the acceptable allowed outage time extension or 30 days, whichever is shorter.
Note: The 30-day limitation may be applied individually to each specification for which Specification 3.13.1 has been entered.
OR Take the ACTION(s) required in the referencing specification(s) for required action or completion time not met SURVEILLANCE REQUIREMENTS 4.13.1 As required by the referencing specification(s)
8 Overview - Sample TS for ECW PLANT SYSTEMS 3/4.7.4 ESSENTIAL COOLING WATER SYSTEM LIMITING CONDITION FOR OPERATION 3.7.4 At least three independent essential cooling water loops shall be OPERABLE.
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTION:
- a. With only two essential cooling water loops OPERABLE, within 7 days restore at least three loops to OPERABLE status or apply the requirements of Specification 3.13.1, or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
- b. With two or more essential cooling water loops inoperable, within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> restore at least two loops to OPERABLE status or apply the requirements of Specification 3.13.1, or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
9 Overview - Scope of Applicable TS AFW MSIVs MFIVs Atmospheric Steam Relief Component Cooling Water Essential Cooling Water Essential Chilled Water SDGs and Off-site circuits Batteries ESF Buses Selected instrumentation of TS 3.3 Code safety valves Pressurizer PORVs Accumulators ECCS RHR RWST RCB Purge Containment Isolation Valves Containment Spray Containment Fan Coolers
10 Implementation
- Same program used for 10CFR50.65(a)(4)
- Routinely used to manage weekly work
- Effectively applied to manage the recent extended diesel generator outage
11 How Risk Values Stack Up Normalized Value Zero-Maintenance CDF Annual Average CDF Average Risk Due to On-Line Maintenance 2
1 0
12 How Risk Values Add Up Cumulative Risk Significance is the increase in the probability of a Core Damage Event due to on-line maintenance
13 PRA Maint. State BOP Maint. State Start End Duration (hh:mm)
PRA Norm.
BOP Norm.
No Risk-Significant Maintenance No Risk-Significant Maintenance 01/17 00:00 01/17 02:00 002:00 0.79 1.00 CCA HEA(EAB)
No Risk-Significant Maintenance 01/17 02:00 01/17 03:00 001:00 3.78 1.00 CCA CSA DGA EWA HEA(EAB)
No Risk-Significant Maintenance 01/17 03:00 01/17 04:00 001:00 6.70 1.00 CCA CHA CSA DGA EWA HEA(EAB)
No Risk-Significant Maintenance 01/17 04:00 01/17 05:00 001:00 6.70 1.00 CCA CHA CSA DGA EWA HEA(EAB) LHA No Risk-Significant Maintenance 01/17 05:00 01/17 14:00 009:00 6.70 1.00 CCA CHA CSA DGA EWA HEA(EAB)
No Risk-Significant Maintenance 01/17 14:00 01/17 19:00 005:00 6.70 1.00 CCA CHA DGA EWA HEA(EAB)
No Risk-Significant Maintenance 01/17 19:00 01/17 20:00 001:00 6.70 1.00 CCA CHA DGA HEA(EAB)
No Risk-Significant Maintenance 01/17 20:00 01/17 21:00 001:00 6.70 1.00 CCA CHA HEA(EAB)
No Risk-Significant Maintenance 01/17 21:00 01/18 03:00 006:00 3.79 1.00 CCA CHA HEA(CR) HEA(EAB)
No Risk-Significant Maintenance 01/18 03:00 01/18 14:00 011:00 3.86 1.00 CCA HEA(CR) HEA(EAB)
No Risk-Significant Maintenance 01/18 14:00 01/18 18:00 004:00 3.86 1.00 HEA(CR) HEA(EAB)
No Risk-Significant Maintenance 01/18 18:00 01/18 21:00 003:00 3.83 1.00 HEA(CR)
No Risk-Significant Maintenance 01/18 21:00 01/19 21:00 024:00 0.87 1.00 No Risk-Significant Maintenance No Risk-Significant Maintenance 01/19 21:00 01/24 00:00 099:00 0.79 1.00 Planned Risk Profiles for Unit 1 Week of 01/17/2005 01/17 01/18 01/19 01/20 01/21 01/22 01/23 01/24 Baseline Trip Risk = 0.036 trips/week 0%
1%
2%
3%
4%
5%
6%
7%
8%
9%
10%
Trip Probability, % increase 0.0% P 01/17 01/18 01/19 01/20 01/21 01/22 01/23 01/24 0e+0 1e-7 2e-7 3e-7 4e-7 5e-7 6e-7 7e-7 8e-7 9e-7 1e-6 CDF Due to Maint.
1.91E-07 P
14 PRA Component Planned Time Non-Functional Planned Time Functional Duration (hh:mm)
Actual Time Non-Functional Actual Time Functional Duration (hh:mm)
CCA 10/26/2004 03:00 10/28/2004 08:00 053:00 10/26/2004 03:00 10/27/2004 13:16 034:16 CHA 10/25/2004 00:00 10/28/2004 11:00 083:00 10/25/2004 00:00 10/28/2004 00:16 072:16 DGA 10/25/2004 03:00 10/28/2004 08:00 077:00 10/25/2004 00:00 10/27/2004 09:05 057:05 EWA 10/25/2004 00:00 10/28/2004 08:00 080:00 10/25/2004 00:00 10/27/2004 04:30 052:30 HEA(CR) 10/25/2004 03:00 10/25/2004 17:00 014:00 10/25/2004 03:00 10/25/2004 12:45 009:45 HHA 10/26/2004 04:00 10/26/2004 23:00 019:00 10/26/2004 04:00 10/27/2004 02:20 022:20 LHA 10/25/2004 23:00 10/28/2004 07:00 056:00 10/25/2004 23:00 10/28/2004 05:17 054:17 LHA 10/25/2004 04:00 10/25/2004 12:00 008:00 10/25/2004 13:47 10/25/2004 16:20 002:33 QDPSA N/A N/A N/A 10/29/2004 19:01 10/29/2004 19:44 000:43 RHRA 10/25/2004 23:00 10/28/2004 08:00 057:00 10/25/2004 23:00 10/28/2004 05:17 054:17 SICA 10/28/2004 13:00 10/28/2004 14:00 001:00 10/28/2004 08:03 10/28/2004 08:33 000:30 BOP Component Planned Time Non-Functional Planned Time Functional Duration (hh:mm)
Actual Time Non-Functional Actual Time Functional Duration (hh:mm)
NONE N/A Actual Risk Profiles for Unit 1 Week of 10/25/2004 10/25 10/26 10/27 10/28 10/29 10/30 10/31 11/01 Baseline Trip Risk = 0.036 trips/week 0%
1%
2%
3%
4%
5%
6%
7%
8%
9%
10%
Trip Probability, % increase 0.0% A 0.0% P 10/25 10/26 10/27 10/28 10/29 10/30 10/31 11/01 0e+0 1e-7 2e-7 3e-7 4e-7 5e-7 6e-7 7e-7 8e-7 9e-7 1e-6 CDF Due to Maint.
2.43E-07 A 3.09E-07 P
15 Application of RITS Example 1: Routine Train A work week with emergent Train B condition Time (hh:mm)
Event Frontstop Calculated AOT (time to reach 1E-05)
Risk
(/hr)
Comment 00:00 Begin Train A work week (SDG, ECW, CCW, HHSI)
HHSI (3.5.2.a): 7 days CCW (3.7..3.a): 7 days ECW (3.7.4.a): 7 days SDG (3.8.1.1.b): 14 days NA, planned to remain within frontstop AOT.
5.9E-09 Routine planned maintenance 24:00 Train B HHSI found to be inoperable 3.5.2.b: 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to apply TS 3.13.1 24 days 1.7E-08 Emergent condition where CTS would require TS 3.0.3 entry. RITS permits the station to address the condition with normal work controls.
36:00 Train B HHSI restored Exit TS 3.5.2.b and TS 3.13.1 applicability.
Back on the work week clock with 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> elapsed.
NA 5.9E-09
16 Application of RITS Example 2: Emergent condition while in configuration where TS 3.13 is in use Time (hh:mm)
Event Frontstop Calculated AOT (time to reach 1E-05)
Risk
(/hr)
Comment 00:00 ECW pump replacement expected to last 10 days.
TS 3.7.4.a: 7 days (Also makes associated SDG inoperable) 1 train of ECW could be allowed OOS up to the 30-day backstop 4.5E-09 TS 3.13.1 requirements apply after 7 days.
The risk is calculated from the time the ECW is taken out of service.
8 days Turbine-driven AFW found to be inoperable TS 3.7.1.2.b: 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> TS 3.8.1.1.d: 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 27 days 1.5E-08 Regardless of the frontstop time for the TDAFW pump, TS 3.13.1 applies because the ECW has gone beyond its frontstop.
TS 3.13.1 requires a determination of the acceptability of the configuration with the additional inoperable TDAFW.
Application of the CRMP would determine the configuration is acceptable.
9 days ECW pump is restored TS 3.7.1.2.b: 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> less the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> that have transpired.
> 30 days (backstop would apply) 1.5E-09 The condition that caused TS 3.13.1 to apply has been exited and there are no TS beyond their frontstop time. The frontstop AOT may be applied to the TDAFW.
17 Application of RITS Example 3: Same as Example 2, except that the emergent condition is restored first Time (hh:mm)
Event Frontstop Calculated AOT (time to reach 1E-05)
Risk
(/hr)
Comment 00:00 ECW pump replacement expected to last 10 days.
TS 3.7.4.a: 7 days 1 train of ECW could be allowed OOS up to the 30-day backstop 4.5E-09 TS 3.13.1 requirements apply after 7 days.
The risk is calculated from the time the ECW is taken out of service 8 days Turbine-driven AFW found to be inoperable TS 3.7.1.2.b: 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> TS 3.8.1.1.d: 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 27 days 1.5E-08 Regardless of the frontstop time for the TDAFW pump, TS 3.13.1 applies because the ECW has gone beyond its frontstop.
TS 3.13.1 requires a determination of the acceptability of the configuration with the additional inoperable TDAFW.
Application of the CRMP would determine the configuration is acceptable.
9 days TD AFW restored NA
> 30 days 4.5E-09 TS 3.13.1 still applies. TDAFW no longer contributes to risk calculation. A new completion time may be calculated.
18 SDG 22 113 Day Extended AOT
- One-time emergency TS Change approved on December 30, 2003
- Configuration risk to be managed by application of the STP Configuration Risk Management Program (CRMP).
- Good example of how the CRMP works
- Duration and risk bound any that would be encountered using proposed RITS
19 SDG 22 113 Day Extended AOT
- Installed non-safety DGs (NDG) as compensatory action
- RG criteria met without credit for NDGs
Comparison of Planned and Actual Risk (ICCDP) for Unit 2 During SDG 22 Outage 0.0E+00 2.0E-06 4.0E-06 6.0E-06 8.0E-06 1.0E-05 08-Dec 15-Dec 22-Dec 29-Dec 05-Jan 12-Jan 19-Jan 26-Jan 02-Feb 09-Feb 16-Feb 23-Feb 01-Mar 08-Mar 15-Mar 22-Mar 29-Mar Date ICCDP NDG Planned Rev 4 Planned Actual NDG Actual DG21 Inspection DG23 Inspection ICCDP Limit (0PGP03-ZA-0091) = 1.0E-05 Data source: NDG Planned - PRA Rev 4 Model including NDG effect on risk (NDG failure and associated operator data are assumed)
Rev 4 Planned - PRA Rev 4 Model assuming no NDG effect on risk Actuals - RAsCAL data for previous work week and PRA Rev 4 ESF "A" Surveillance 3/31/04 8.17E-6 3/31/04 NDG 3.04E-6 Projected Actual for 3/31/04 8.17E-6 ECW2B
- PRA quality needed for 4B application will also be evaluated