Methodologies for Determination of Instrument Set Points for Nuclear Plants (ISA 67.04)

1
Methodologies for Determination of Instrument Set
Points for Nuclear Plants (ISA 67.04)

• Dr. Ramesh Shankar
• Signatech Systems, Inc.
• Solving Tomorrows Energy Problems Today TM

2
Overview

• Provides guidance in
• calculating total channel uncertainty
• estimating uncertainties
• common practices
• sources interpretation of data

3
Overview ??

• ??????
• total channel uncertainty???
• Uncertainties???
• ?????
• ??????????????

4
Typical Instrument Channel Layout

• Process
• Process Interface
• Process Measurement
• Signal Interface
• Signal Conditioning
• Actuation

5
Typical Instrument Channel Layout

• Process ????
• Process Interface ????????????
• Process Measurement ??????
• Signal Interface ??????????
• Signal Conditioning ?????????
• Actuation ??

6
Setpoint Calculation Flow Chart
7
Setpoint Calculation Flow Chart
8
Uncertainty Equation
9
Uncertainty Equation (??????)

• ???????????????????????????????????
• ?????????????(?????????????????)?????????????????
  ??????????????????????????????????????????????????
  ?????????????????
• ????(????????)????????????????????????????????????
  ?????????????-??????
• ???????

10
Maximum Positive Uncertainty
11
Maximum Positive Uncertainty???????????
12
Maximum Negative Uncertainty
13
Maximum Negative Uncertainty????????????
14
Total Channel Uncertainty
15
Total Channel Uncertainty????????????

• ?????????????????????????????????
• ??????????????????????????????????????????????????
  ?????????
• ?????1???????n??????????????????????????????
• ??????????????????????????????????????????????????
  ???????
• ?????????????????????????????????PME?PEA??????????
  ??????????????????????????????????
• ??????????????????????????????????PME?PEA?????????
  ???????????????????????????????????

16
Sensor Uncertainty (Module 1)
17
Sensor Uncertainty (Module 1)?????????(?????1)
18
As-Found As Left Uncertainty
19
As-Found As Left Uncertainty(As Found As
left?????)

• ?????????
• ???????????????
• ?????????????????????????????????
• ??????????????????????????????????
• ????????????????????????????????
• ??????????????????????????????
• ????????????????????
• ????????????????????????????????
• ??????????????????????????????????
• ???????????????????????????????????????????
• ?????????????????????????????????????
• ?????????????

20
Setpoint relationships per ISA 67.04
21
Setpoint relationships per ISA 67.04(ISA
67.04???????????)
22
Trip Setpoint
23
Trip Setpoint(????????)

• ????????
• ??????
• ??????????????????????
• ?????????????????????????????????????????????????
  ??????????

24
Instrument Drift and Uncertainty

25
Instrument Drift and Uncertainty????????????

??????????????????? ?????????????????????? ???????
??? ?????????? ?????????? ???????????? ???????????
??
26
Instrument Drift
27
Instrument Drift???????
28
AFAL Analysis
29
AFAL AnalysisAFAL??

• ???????AFAL????????????????????1.35???????????0.0
  7????????
• ???1.35?SA, SD, SMTE?????D????????????????
• AFAL?????????????????????????
• ????????????????

30
Conclusions

• The setpoint could be changed. This might be
  desired if the margin between the setpoint and
  the normal system operating point was very small.
• The setpoint could remain the same with the lower
  sensor uncertainty resulting in additional margin
  between the setpoint and the safety limit.
• Basis for not changing setpoints for longer
  refueling cycles, i.e., from 12 months to 18
  months

31
Conclusions(??)

• ??????????? ??????????????????????????????????
• ??????????????????????????????????????????????????
  ????????????????
• ?????????????????????????????????????12????18????