NUREG/CR-4551, Vol. 2, Rev. 1, Part 1, "Evaluation of Severe Accident Risks: Quantification of ...

303 Pages·2004·11.48 MB·English

8524 J. A. Wackerly
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NUREG/CR-455 1
8232-21 /071149 SAND86-1309
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Evaluation of
Severe Accident Risks:
Quantification of
Major Input Parameters
Expert Opinion Elicitation on In-Vessel Issues
Prepared by
I'. 1'. Harper, R. J. Breeding, T. D. Brown, J. J. Gregory,
A. C. Payne, E. D. Gorham, C. N. Amos
Sandia National Laboratories
Operated by
Sandia Corporation
Prepared for
U.S. Nuclear Regulatory Commission
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NUREGICR-4551
SAND86-1309
Vol. 2, Rev. 1, Part 1
Evaluation of
Severe Accident Risks:
Quantification of
Maj or Input Parameters
Expert Opinion Elicitation on In-Vessel Issues
Manuscript Completed: November 1990
Date Published: December 1990
Prepared by
F. T. Harper, R. J. Breeding, T. D. Brown, J. J. Gregory,
A. C. Payne, E. D. Gorham, C. N. Amos'
Sandia National Laboratories
Albuquerque, NM 87185
Prepared for
Division of Systems Research
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555
NRC FIN A1853
'Science Applications International Corporation, Albuquerque, NM

ABSTRACT
This report records part of the vast amount of information received
during the expert judgment elicitation process that took place in support
of the NUREG-1150 effort sponsored by the U.S. Nuclear Regulatory
Commission. The results of the In-Vessel Expert Panel are presented in
this part of Volume 2 of NUREG/CR-4551. The In-Vessel Panel considered
six issues:
1. Temperature-Induced pressurized water reactor (PWR) Hot Leg or Surge
Line Failure Before Vessel Breach;
2. Temperature-Induced Steam Generator Tube Rupture (SGTR) Before Vessel
Breach ;
3. Boiling water reactor (BWR) In-Vessel Hydrogen Production;
4. BWR Bottom Head Failure;
5. PWR In-Vessel Hydrogen Generation;
6. PWR Bottom Head Failure.
The report begins with a brief discussion of the methods used to elicit
the information from the experts. The information for each issue is then
presented in five sections: (1) a brief definition of the issue, (2) a
brief summary of the technical rationale supporting the distributions
developed by each of the experts, (3) a brief description of the
operations that the project staff performed on the raw elicitation
results in order to aggregate the distributions, (4) the aggregated
distributions, and (5) the individual expert elicitation summaries. The
individual expert elicitation summaries were written soon after the
elicitation and were sent to the experts for review. They represent the
raw results as received directly from the experts.
iii/iv

CONTENTS
. ..................................................
1 INTRODUCTION 1.1
. ............................................
2 EXPERT CREDENTIALS 2.1
. ...................................................
3 METHODOLOGY 3.1
............................................
3.1 Introduction 3.1
.........................
3.2 Steps to Elicit Expert Judgment 3.2
.....................................
3.3 Selection of Issues 3.2
....................................
3.4 Selection of Experts 3.7
....................................
3.5 Elicitation Training 3.7
..................................
3.6 Presentation of Issues 3.10
..................
3.7 Preparation and Discussion of Analyses 3.10
.............................................
3.8 Elicitation 3.11
................
3.9 Recomposition and Aggregation of Results 3.12
..................................................
3.10 Review 3.13
...........................................
3.11 Documentation 3.13
. ..........................................
4 ELICITATION MEETINGS 4.1
.
5 RESULTS OF THE ELICITATION ON EACH IN-VESSEL
ISSUE .......................................................5. 1.1
.
5.1 Issue 1 Temperature-Induced PWR Hot Leg or Surge
.............
Line Failure Before Vessel Breach 5.1-1
.
5.2 Issue 2 Temperature-Induced Steam Generator Tube
............
Rupture (SGTR) Before Vessel Breach 5.2-1
. ...............
5.3 Issue 3 BWR In-Vessel Hydrogen Production 5.3-1
. .........................
5.4 Issue 4 BWR Bottom Head Failure 5.4-1
. ...............
5.5 Issue 5 PWR In-Vessel Hydrogen Generation 5.5-1
. .........................
5.6 Issue 6 PWR Bottom Head Failure 5.6-1
........................................................
APPENDIX A A-1
........................................................
APPENDIX B B-1
........................................................
APPENDIX C C-1
V
............. ................ -.__....-. ......... ............
.__1.--... 1.
FIGURES
. .......................
1 Back-End Documentation for NUREG-1150 xiv
Issue 1
..........
1-1 Expert A: Case 1: Induced Hot Leg Failure in PWRs 5.1-6
..........
1-2 Expert C: Case 2: Induced Hot Leg Failure in PWRs 5.1-6
................................
A-1 Induced Hot Leg LOCA. Case 1 5.1 .14
................................
A-2 Induced Hot Leg LOCA, Case 2 5.1 .15
...............................
C-1 Expert C's Decomposition Tree 5.1-26
Issue 2
................................
2-1 PWR Temperature-Induced SGTR 5.2-3
A-1 Average Wall Temperature Versus Rupture Time
...................................
for Steam Generator Tube 5.2-8
A-2 Average Wall Temperature Versus Rupture Time
...........................................
for Hot Leg Pipe 5.2-8
A-3 Temperatures Through Hot Leg Wall at Nozzle..
.........................................
Hot Leg Connection 5.2-9
B-1 Average Wall Temperature Versus Rupture
................
Time for Steam Generator Tube (Inconel 600) 5.2-15
Issue 3
...............................
3-1 Case la: Before Vessel Breach 5.3-7
...............................
3-2 Case lb: Before Vessel Breach 5.3-7
...............................
3-3 Case 2a: Before Vessel Breach 5.3-8
...............................
3-4 Case 2b: Before Vessel Breach 5.3-8
...............................
3-5 Case 3a: Before Vessel Breach 5.3-9
...............................
3-6 Case 3b: Before Vessel Breach 5.3-9
vi
FIGURES (Continued)
................
A-1 Expert A's Decomposition for Cases la and lb 5.3-14
..................
A-2 Expert A's Assessments for Cases la and lb 5.3-16
A-3 Expert A's Assessments for Cases 2a and 2b .................... 3-17
A-4 Expert A's Assessments for Cases 3a and 3b .................... 3.18
.
A-5 Calculated Cumulative Probability Distribution
Functions For Total Hydrogen Production
Through All Four States ....................................5. 3.19
B-1 Summary Results of Expert B .................................5. 3.26
...................
B-2 Timing of Hydrogen Production for Case la 5.3-26
...................
B-3 Timing of Hydrogen Production for Case lb 5.3-27
...................
B-4 Timing of Hydrogen Production for Case 2a 5.3-27
...................
B-5 Timing of Hydrogen Production for Case 2b 5.3-28
...................
B-6 Timing of Hydrogen Production for Case 3a 5.3-28
.....
C-1 Case 2a Assessments of Hydrogen Production for Expert C 5.3 -33
.....
C-2 Case la Assessments of Hydrogen Production for Expert C 5. 3.35
......
C-3 Case 3 Assessments of Hydrogen Production for Expert C 5. 3.35
C-4 Timing of Hydrogen Production Using Judgments
of Expert C for Case la ....................................5. 3.36
C-5 Timing of Hydrogen Production Using Judgments
of Expert C ................................................5. 3.36
D-1 Expert D's Hydrogen Production Estimate
..................................
in Two Stages for Case la 5.3-40
D-2 Timing of Hydrogen Production Using Judgments
of Expert D ................................................5. 3-42
.............
D-3 Assessment for Hydrogen Production for Expert D 5.3 -44
Issue 4
A-1 Expert A's Decomposition Tree for BWR
........................................
Bottom Head Failure 5.4-7
vii
~-~~~
... II_..__- ......... ............ ... -. . 1-. .. -.. ..,. ... ---. ........
FIGURES (Continued)
Issue 5
..................
5-1 Expert A: Percentage oE Oxidized Zirconium 5.5-14
..................
5-2 Expert B: Percentage of Oxidized Zirconium 5.5-14
..................
5-3 Expert C: Percentage of Oxidized Zirconium 5.5-15
..................
5-4 Expert D: Percentage of Oxidized Zirconium 5.5-15
......................
5-5 Expert E: Amount of Hydrogen Generated 5.5-16
.............................
5-6 Aggregate of Oxidized Zirconium 5.5-16
5-7 Case la: RCS Percentage of Zirconium Oxidized
..........................................
when at 2500 psia 5.5-17
5-8 Case lb: RCS Percentage of Zirconium Oxidized
..........................................
when at 2500 psia 5.5-17
5-9 Case IC: RCS Percentage of Zirconium Oxidized
..........................................
when at 2500 psia 5.5-18
5-10 Case 2a: RCS Percentage of Zirconium Oxidized
..................................
when at 1000 to 1500 psia 5.5-18
5-11 Case 2b: RCS Percentage of Zirconium Oxidized
..................................
when at 1000 to 1500 psia 5.5-19
5-12 Case 2c: RCS Percentage of Zirconium Oxidized
..................................
when at 1000 to 1500 psia 5.5-19
5-13 Case 3a: RCS Percentage of Zirconium Oxidized
....................................
when at 150 to 500 psia 5.5-20
5-14 Case 3b: RCS Percentage of Zirconium Oxidized
....................................
when at 150 to 500 psia 5.5-20
5-15 Case 4: RCS Percentage of Zirconium Oxidized
.....................................
when at 40 to 200 psia 5.5-21
5-16 Case 5: RCS Percentage of Zirconium Oxidized
..................................
when at 1000 to 1500 psia 5.5-21
...................................................
A-1 Case 1 5.5-26
...................................................
A-2 Case 2 5.5-26
...................................................
A-3 Case 3 5.5-27
....................................
D-1 Expert D's Decomposition 5.5-46
viii