sdp introduction: 'significance determination …the significance determination process."...
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Sdp \ Introduction \SDPpowerpoint.pdf
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SignificanceDetermination Process
Technical Training CenterChattanooga, Tennessee
Learning Objectives
" Given a scenario, use IMC-0612,Appendix B to determine if an issue hassufficient significance to warrant use ofthe significance determination process.
" Given a scenario, use IMC-0609,Appendix A, and a Phase 2 pre-solvedtable to determine the risk significance.
Technical Training CenterChattanooga, Tennessee
.Purpose of SDP
* The Significance DeterminationProcess (SDP) uses risk insights,where appropriate, to help the NRCinspectors and staff to determinethe safety significance ofinspection findings.
Technical Training CenterChattanooga, Tennessee
SDP Objectives* To characterize the significance of
an inspection finding for the NRClicensee performance assessmentprocess, using best available riskinsights as appropriate.
The SDP thus assigns a color to theinspection finding.
Technical Training CenterChattanooga, Tennessee
Exhibit 2: REACTOR OVERSIGHT PROCESS
Communications
Agency Response
Management Conference
Monitor Licensee Actionsr-- - ---------- ------.......... i NRC Rlati ActionsL ...........
- -- ... .....
Additional Regulatory Actions
Assessment Process
(Action Matrix)
Public Meetings
" Press Releases" NRC Web Site" PDR/ADAMS
Assessment ReportsInspection Plans
Inspection FindingsPerformance Indicators
Signi~fica
Enforcement
4i
Cornerstones of Safety
'nee Evaluations I Significance Evaluations
Significance Deterlnination Proces'S Performance Indicator Thresholds
mA A
A.A|, I
* i
* i
Supplemental Event ResponseInspections (SI/AIT/IIT) [
Inspections
A
-I
Generic Safety Risk InformedInspections Baseline Inspections
)k--------------------------- ---------------------------
Performance Indicators
Performance Indicators
r- I Performance Results in all 7 Cornerstones of Safety m
Technical Training CenterChattanooga, Tennessee
SDP Colors
GreenACDF
- very low safety significance.< 1E-6
White - low to moderate safety significance.1E-6 < ACDF < 1E-5
Yellow - substantial safety significance.1E-5 <ACDF < 1E-4
Red - high safety significance.1E-4 < ACDF
Technical Training CenterChattanooga, Tennessee
SDP Objectives(Continued)
" To provide all stakeholders an objectiveand common framework forcommunicating the potential safetysignificance of inspection findings.
" To provide a basis for assessmentand/or enforcement actions associatedwith an inspection finding.
" To provide the inspectors with plant-specific risk information for use in risk-informing the inspection program.
Technical Training CenterChattanooga, Tennessee
Types of SDPs
* At least one SDP supports eachcornerstone associated with thestrategic performance areasdefined in IMC 2515.
e The SDPs and related instructionsare found in IMC 0609.
Technical Training CenterChattanooga, Tennessee
Exhibit 1: REGULATORY FRAMEWORK
Cornerstones
SHUMAN -------- SAFETY CONSCIOUS WORK --------- PROBLEM --------PERFORMANCE ENVIRONMENT IDENTIFICATION AND
RESOLUTION
Cross-Cutting Areas
Technical Training CenterChattanooga, Tennessee
SDP ListingA. Significance Determination of
Reactor Inspection Findings forAt-Power Situations
B. Emergency Preparedness SDPC. Occupational Radiation Safety
SDPD. Public Radiation Safety SDPE. Physical Protection SDPF. Fire Protection SDP
Technical Training CenterChattanooga, Tennessee
SDP ListingG. Shutdown Safety SDPH. Containment Integrity SDPI. Operator Requal. Human
Performance SDPJ. SG Tube Integrity Findings SDPK. Maint. Risk Assess. & Risk
Management SDPM. Significance Determination
Process Using Qualitative CriteriaTechnical Training CenterChattanooga, Tennessee
Determining theSignificance of Reactor
Inspection Findings for At-Power Situations
Technical Training CenterChattanooga, Tennessee
Entry Conditions
* This SDP provides a simplified risk-informed framework to estimatethe increase in core damagefrequency during at-powersituations due to conditions whichcontribute to unintended risk.increases caused by de)Ocoimý
Technical Training CenterChattanooga, Tennessee
Deficient Performance
L_ VV(]., is an issue that isthe result of a licensee not meeting arequirement or standard where thecause was reasonably within thelicensee's ability to foresee and correct,and that should have been prevented. Aperformance deficiency can exist if alicensee fails to meet a self-imposedstandard or a standard required byregulation. IMC 0612.
Technical Training CenterChattanooga, Tennessee
Examples of DeficientPerformance
" Safety-related pump dischargevalve remained closed followingsurveillance testing.
* Debris left in safety-related tankfollowing maintenance activities.
" Failing to take proper correctiveaction when testing demonstrateda problem.
Technical Training CenterChattanooga, Tennessee
Entry Conditions (Cont'd)" Conditions which do not represent deficient
licensee performance are considered part ofthe acceptable plant risk and are notcandidates for SDP evaluation.
" Each Issue should be screened by using IMC0612, Appendix B, to determine whetherthe issue is more than a minor issue.
" If issue is not minor, then it is a candidatefor SDP evaluation.
" This SDP is not used for event evaluation.
Technical Training CenterChattanooga, Tennessee
Use Figure 1 and the questions listed below to determine if a finding has sufficientsignificance to warrant further analysis or documentation.
Figure 1
IMC 0612
Appendix B:
IssueScreening
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see exception inSection 05.03
IMC-0612
Appendix BGreater
Yesl Figure 1App. E?
Greater
Minor
Yes
Technical Training CenterChattanooga, Tennessee
Issue
Performance DeficiencyQuestion
* Did the licensee fail to meet a requirementor standard, where the cause wasreasonably within the licensee's ability toforesee and correct and which shouldhave been prevented?
* A performance deficiency can exist if alicensee fails to meet a self-imposedstandard or a standard required byregulation.
Technical Training CenterChattanooga, Tennessee
Traditional EnforcementQuestions
* Does the issue have actual safetyconsequence (overexposure, excessiveradioactive release)?
* Does the issue have the potential forimpacting the NRC'Fs ability to performits regulatory function?
* Are there any willful aspects of theViolation?
Technical Training CenterChattanooga., Tennessee
Minor Questions* Could the issue be reasonably viewed as a
precursor to a significant event?* If left uncorrected, could the finding become a
more significant safety concern?• Does the finding relate to a performance
indicator that would have caused the PI toexceed a threshold?
* Is the finding associated with one of thecornerstone attributes listed at the end of thisattachment and does the finding affect theassociated cornerstone objective?
* 9 maintenance risk assessment and riskmanagement questions (not listed here).
Technical Training Center > Objectives Figure I
Chattanooga, Tennessee IJ>
Initiating Events
* Objective - to limit the likelihood ofthose events that upset plant stabilityand challenge critical safety functionsduring shutdown as well as poweroperations.
* Attributes: design control, protectionagainst external factors, configurationcontrol, equipment performance,procedure quality, and humanperformance.
Technical Training CenterChattanooga, Tennessee
Mitigating Systems
" Objective - to ensure the availability,reliability, and capability of systemsthat respond to initiating events toprevent undesirable consequences (i.e.,core damage).
* Attributes: design control, protectionagainst external factors, configurationcontrol, equipment performance,procedure quality, and humanperformance.
Technical Training CenterChattanooga, Tennessee
Barrier Integrity
" Objective - to provide reasonableassurance that physical design barriers(fuel cladding, RCS, and containment)protect the public from radionuclidereleases caused by accidents.
" Attributes: design control, configurationcontrol, procedure quality, humanF erformance, cladding performancecladding), RCS equipment and barrier
performance (RCS), and SSC and barrierperformance (containment).
Technical Training CenterChattanooga, Tennessee E
SDP Questions" Is the event associated with an increase in the
likelihood of an initiating event?" Is the finding associated with the operability,
availability, reliability, or function of a systemor train in a mitigating system?
" Is the finding associated with the integrity offuel cladding, the reactor coolant system,reactor containment, control room envelope,auxiliary building (PWR), or ... (BWR)?
" Is the finding associated with degradedconditions that could concurrently influence anymitigation equipment and an initiating event?
Technical Training CenterChattanooga, Tennessee
SDP Questions (cont'd)* Is the finding associated with or involve
impairment or degradation of a fireprotection feature?
" Is the finding associated with the spentfuel pool cooling system radiologicalbarrier?
" Is the finding associated with inadequate10 CFR 50.65(a)(4) risk assessment(quantitative only) and/or riskmanagement?
Technical Training CenterChattanooga, Tennessee
SDP Phases
* Phase 1 - Characterization and InitialScreening of Findings
Characterization of the finding and an initial screening oflow-significance findings for disposition by the licensee'scorrective action program.
* Phase 2- Risk Significance Estimation andJustification Using the Site Specific Risk-Informed Inspection Notebook and Pre-SolvedTable* Plant-specific estimation of the risk significance of an
inspection finding and development of the basis for thedetermination.
Technical Training CenterChattanooga, Tennessee
SDP Phases(Continued)
* Phase 3 - Risk SignificanceEstimation Using Any Risk BasisThat Departs from the Phase 1 orPhase 2 Processe Any departure from the guidance provided for
Phase 1 or 2 constitutes a Phase 3 analysis.Phase 3 analysis methods will utilize appropriatePRA techniques and rely on the expertise of NRCrisk analysts.
Technical Training CenterChattanooga, Tennessee
Determine Applicable Scenarios from Table 2.
* I T 1 1 7
TPCS AFW I EIHP FB HPR STATUS
Initiating EventLikelihood(Table 1)
Mitigation Capability- Table 41
2
3
OK
OK
CID
CD
CD
4
5
Plant name abbrev.: CALL
Technical Training CenterChattanooga, Tennessee
Table 3.X for each scenario
A Little Math
* If events A and B are independent,then the Pr(A and B) is:
Pr(A and B) - Pr(A) Pr(B)
* Logarithms
log AB logA + log BTechnical Training CenterChattanooga, Tennessee
SDP Tables* In IMC - 0609
-Table 4, Remaining Mitigation Capability Credit
- Table 51 Counting Rule Worksheet
* In Site Specific Workbook-Table 1, Categories of Initiating Events
- Table
- Table
21Initiators and Dependency
3.X1 Worksheets for required initiatingevent scenarios.
Technical Training CenterChattanooga, Tennessee
Example using notebook
TDAFWIssue
Technical Training CenterChattanooga, Tennessee
SDP Phase 2 Steps(IMC 0609, App. A, Att. 1)
Step 2.1.1: Check for the mostcurrent version of SDPNotebook and Pre-solvedWorksheet.
Step 2.1.2: Determine theexposure time.
Technical Training CenterChattanooga, Tennessee
1.1 Exposure Time
If the inception of the condition isunknown:- determine last successful demonstration of
functionality.
- Exposure time = (date discoveredinoperable - date of functionalitydemonstration)/2
- called t/2
Technical Training CenterChattanooga, Tennessee
SDP Phase 2 Steps(IMC 0609, App. A, Att. 1 cont'd)Step 2.1.3: Find the appropriate target for
the inspection finding in the pre-solvedtable.
Step 2.1.4: Determine the risk significanceof the inspection finding and thepotential risk contribution due to LargeEarly Release Frequency (LERF).
Technical Training CenterChattanooga, Tennessee
SDP Phase 2 StepsI[IMC 0609, App. A, Att. 1- conStep 2.1.5: Screen for the potential risk
contribution due to external events ifresults from Step 2.1.4 are Green andgreater than or equal to 1E-7.
t'd)
is
Technical Training CenterChattanooga, Tennessee