Transcript Slide 1

Summary Report of the EPRI
Standard Radiation Monitoring
Program
Dennis Hussey, EPRI
Asian Technical Center ALARA Symposium
Yuzawa, Japan
October 11-13, 2006
Overview
• History of Standard Radiation Monitoring Program (SRMP)
• Standard Radiation Monitoring Program Goals
• Plant Types and Survey Points
• Current Results
– US Responses
– Summary statistics of
• loop piping
• channel head surveys
– Difference of cold leg and hot leg measurements
• Conclusions and Recommendations
© 2006 Electric Power Research Institute, Inc. All rights reserved.
2
History of Standard Radiation Monitoring
Program (SRMP)
• Started in 1978 to study radiation fields in Westinghousedesigned plants
– Program expanded to include Combustion
Engineering (CE) designs
– In 1996, program was suspended because of a lack of
industry interest and funding
• In 2003, NEI/INPO/EPRI developed the RP2020 Dose
Reduction initiative
– Take Radiation Off the Table
– EPRI was charged to take the technical lead for
source term reduction
– First goal was to benchmark PWR performance
© 2006 Electric Power Research Institute, Inc. All rights reserved.
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Standard Radiation Monitoring Program Goals
• Maintain the history of the program
– Much data have been acquired already
– Locations should not be change
• Make the procedure simple, focused, practical, and routine
– North American Technical Center recommendation
– Help HP staff so that HP staff can help us
• Organize the data to allow correlation to chemistry events
and plant design
– PWR Monitoring and Assessment Database
• Encourage consistent sampling techniques
© 2006 Electric Power Research Institute, Inc. All rights reserved.
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SRMP Monitoring Points
• Workshop held in Charlotte March 7-9, 2006 to discuss
– Selection of B&W points
– Required vs Recommended points
– Procedure clarifications
• Marker Discussions
– Emergency Core Coolant System strainers limit
markers with vinyl
– New markers made that are etched stainless steel
• Discussed further SRMP plans
– Pre-oxidation points
– Auxiliary system monitoring
– Possible smears
© 2006 Electric Power Research Institute, Inc. All rights reserved.
5
Westinghouse Monitoring Points
Loop piping
Crossover piping and SG
Hot leg piping
Cold leg piping
Steam Generator Channel Head
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Combustion Engineering Monitoring Points
Loop piping
Steam Generator Channel Head
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Babcock and Wilcox Monitoring Points
Steam Generator Channel Head
Loop piping
© 2006 Electric Power Research Institute, Inc. All rights reserved.
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Current US Survey Results
Parameter/Plant Type
W
CE
B&W Total
Plants
Total Number of Outages
Loop Dose Rate Measurements
Channel Head Dose Rate
Measurements
% Loop Measurements Received
% Channel Head Measurements
Received
33/48
982
733
538
5/14
275
60
27
5/7
180
48
42
43/69
1437
841
607
74.6
54.8
21.8
9.8
26.7
23.3
58.5
42.2
© 2006 Electric Power Research Institute, Inc. All rights reserved.
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Summary Statistics:
Loop Piping—Hot Leg and Cold Leg
8.00
7.00
Dose rate (mSv/hr)
6.00
Average (mSv/hr)
Standard Deviation (mSv/hr)
Max (mSv/hr)
Min (mSv/hr)
5.00
4.00
3.00
2.00
1.00
0.00
Hot
Leg
Cold
Leg A
CE
Cold
Leg B
Hot
Leg
J-leg A J-Leg
B
B&W
Hot
Leg
W 3 loops
Plant Type/Loop Location
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Cold
Leg
Hot
Leg
Cold
Leg
W 4 Loops
Summary Statistics:
Channel Head Center
350.0
300.0
Average (mSv/hr)
Standard Deviation (mSv/hr)
Max (mSv/hr)
Min (mSv/hr)
Dose rate (mSv/hr)
250.0
200.0
150.0
100.0
50.0
0.0
Point 2
Point 6
CE
Point 2
Point 10
Point 2
W 3 Loop
W 4 Loop
Plant Type/Location
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Point 10
11
Point 2
Point 8
B&W
Summary Statistics:
Channel Head, Cold Leg - Hot Leg Difference
Channel Head Dose Rate Difference (mSv/hr)
200
Average (mSv/hr)
Standard Deviation (mSv/hr)
Max (mSv/hr)
Min (mSv/hr)
150
100
50
0
-50
Pt10-Pt2
Pt10-Pt2
Pt6-Pt2
Pt8-Pt2
W 3 Loops
W 4 Loops
CE
B&W
-100
-150
Plant Type/Points
© 2006 Electric Power Research Institute, Inc. All rights reserved.
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Conclusions
•
•
•
•
•
The Standard Radiation Monitoring Program has been re-instated
The procedures have been simplified for the HP staff
Babcock and Wilcox plants are now included in the program
The historical measurement points have been maintained for reference
The data variability is quite large over time
– Westinghouse-designed plants have largest limits, and longest history
– Summary stats are not enough for a quantitative analysis of dose rates
• The trend of the cold leg having higher radiation fields than the hot leg has
been confirmed for Westinghouse and CE plants
– Unexpected results obtained for the B&W plants
© 2006 Electric Power Research Institute, Inc. All rights reserved.
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Recommendations
• Analyze the data to evaluate the change in radiation
fields over time
– Time-based data will help understand transient
changes in radiation fields
– Effects of system changes will be observable
• Compare the plants by chemistry operations, steam
generator materials, and core duty
– SRMP database is combined with the EPRI PWR
Chemistry Monitoring and Assessment Database
– Combined database also includes
• Steam generator information
• Limited core duty
© 2006 Electric Power Research Institute, Inc. All rights reserved.
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Acknowledgements
• EPRI Solutions
– Sam Choi, Cara Libby
• PWR ALARA Group
– Leonard Rollins, Dan Stoltz
• North American Technical Center
– David Miller, Scott Schofield
• Romain Bouchacourt
© 2006 Electric Power Research Institute, Inc. All rights reserved.
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