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
Setpoints for SafetyRelated Instrumentation DG1141 (RG1.105r4) Public meeting of 14August2014 Introductory Presentation 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 1
Setpoints for SafetyRelated Instrumentation DG1141 (RG1.105r4) Public meeting of 14August2014 Introductory Presentation Sometimes, things go wrong.
2 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.
- 10CFR50.36(c)(1)(ii)(A) 3 1
Setpoints for SafetyRelated Instrumentation DG1141 (RG1.105r4) Public meeting of 14August2014 Introductory Presentation Plant Protection Continuum Plant Safety Is demonstrated by Safety Analyses Are enforced by Technical Specifications Are established by Instrument Setpoint Calculations Are based upon Device Uncertainty Data 4
Key Setpoint Parameters AL TLU AsF (Acceptable)
LSP +AFT pAsL AsL As-Found Reference
+ST
-AFT NSP
-ST AsF (Unacceptable) 5 2
Setpoints for SafetyRelated Instrumentation DG1141 (RG1.105r4) Public meeting of 14August2014 Introductory Presentation Key Setpoint Parameters AL TLU AV AsF (Looks Unacceptable)
LSP pAsL AsL +AFT
+ST NSP ??? As-Found Reference
-ST
-AFT AsF (Looks Acceptable) 6 The Cycle of Adjustment and Confirmation Data Expectations Analysis Establish Revise TS?
TS Observation 7
3
Setpoints for SafetyRelated Instrumentation DG1141 (RG1.105r4) Public meeting of 14August2014 Introductory Presentation 95/95 vs Probability of Trip 100%
97.5%
95%
95% of random errors within 95/95 limits 50%
2.5% of 2.5% of random errors random errors outside 95/95, outside 95/95, within AL beyond AL LSP AL bias random Total Loop Uncertainty 8
Malfunction-Induced Deviation Histograms of AsFound values For no malfunction and for Malfunction-Induced Deviations of 1 and 2 times the Deviation Limit DL DL 2 1 0 1 2 3 4 Observed Deviation, in units of Deviation Limits 9
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