ML14218A012
| ML14218A012 | |
| Person / Time | |
|---|---|
| Issue date: | 08/14/2014 |
| From: | Paul Rebstock NRC/RES/DE/DICB |
| To: | |
| Rebstock P | |
| References | |
| DG-1141, NRC-2014-0163 RG-1.105, Rev. 4 | |
| Download: ML14218A012 (5) | |
Text
SetpointsforSafetyRelatedInstrumentation DG1141(RG1.105r4) Publicmeetingof14August2014 IntroductoryPresentation 1
Setpoints for Safety-Related Instrumentation An Overview of Draft Regulatory Guide DG-1141 (proposed revision 4 to Regulatory Guide 1.105)
ADAMS Accession Number ML081630179 Issued for Public Comment on July 11, 2014 Federal Register Notice NRC-2014-0163 Comments Due October 10, 2014 Paul Rebstock, NRC Office of Nuclear Regulatory Research (RES/DE/ICEEB)
August 14, 2014
SetpointsforSafetyRelatedInstrumentation DG1141(RG1.105r4) Publicmeetingof14August2014 IntroductoryPresentation 1
2 Sometimes, things go wrong.
Twofold Objective
- Confirming the Past
- As-Found Limits provide a basis for confidence that the instrumentation has behaved as expected.
- Protecting the Future
- As-Left Limits help to ensure that the instrumentation will initiate action when it is needed.
SetpointsforSafetyRelatedInstrumentation DG1141(RG1.105r4) Publicmeetingof14August2014 IntroductoryPresentation 2
Plant Protection Continuum 4
Plant Safety Is demonstrated by Safety Analyses Technical Specifications Instrument Setpoint Calculations Are enforced by Are established by Device Uncertainty Data Are based upon AsF (Acceptable)
AsL pAsL
-ST Key Setpoint Parameters 5
+ST TLU
-AFT
+AFT As-Found Reference AsF (Unacceptable)
SetpointsforSafetyRelatedInstrumentation DG1141(RG1.105r4) Publicmeetingof14August2014 IntroductoryPresentation 3
AsL pAsL
-ST Key Setpoint Parameters 6
+ST TLU AV
???
-AFT
+AFT As-Found Reference AsF (Looks Unacceptable)
AsF (Looks Acceptable)
Establish TS Revise TS?
The Cycle of Adjustment and Confirmation 7
Observation Analysis Data Expectations
SetpointsforSafetyRelatedInstrumentation DG1141(RG1.105r4) Publicmeetingof14August2014 IntroductoryPresentation 4
95/95 vs Probability of Trip 8
50%
Total Loop Uncertainty AL LSP bias random 95%
97.5%
100%
50%
Total Loop Uncertainty AL LSP bias random 2.5% of random errors outside 95/95, within AL 2.5% of random errors outside 95/95, beyond AL 95% of random errors within 95/95 limits Malfunction-Induced Deviation 9
2
1
0 1
2 3
4 DL
DL Observed Deviation, in units of Deviation Limits Histograms of AsFound values For no malfunction and for Malfunction-Induced Deviations of 1 and 2 times the Deviation Limit