Evaluation of Severe Accident Risks

445 Pages·2012·10.68 MB·English

NUREG/CR— 4551-Vol. 2-Rev. 1-Pt. 2
TI91 Oil j>55
Evaluation of
Severe Accident Risks:
Quantification of
Major Input Parameters
Experts' Determination of Containment Loads and
Molten Core Containment Interaction Issues
Manuscript Completed: February 1991
Date Published: April 1991
Prepared by
F. T. Harper, A. C. Payne, R. J. Breeding, E. D. Gorham, T. D. Brown,
G. S. Rightley, J. J. Gregory, W. Murfin1, C. N. Amos2
Sandia National Laboratories
Albuquerque, NM 87185-5800
Prepared for
Division of Systems Research
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555
NRC FIN A1228
’Technadyne Engineering Consultants, Inc., Albuquerque, NM
2Science Applications International Corporation, Albuquerque, NM
DISTRIBUTION O ' TW- nnAjM FM T IS UNLIMITED
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 Containment Loads and Molten Core/Containment
Interaction Expert Panel Elicitation are presented in this part of Volume
2 of NUREG/CR-4551. The Containment Loads Expert Panel considered seven
issues:
1. Hydrogen Phenomena at Grand Gulf;
2. Hydrogen Burn at Vessel Breach at Sequoyah;
3. BWR Reactor Building Failure Due to Hydrogen;
4. Grand Gulf Cor.tainment Loads at Vessel Breach;
5. Pressure Increment in the Sequoyah Containment at Vessel Breach;
6. Loads at Vessel Breach: Surry;
7. Pressure Increment in the Zion Containment at Vessel Breach.
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 elicifation 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.
The Molten Core/Containment Interaction Panel considered three issues.
The results of the following two of these issues are presented in this
document:
1. Peach Bottom Drywell Shell Meltthrough;
2. Grand Gulf Pedestal Erosion.
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 Issue j .............................................. 3.2
3.4 Selection of Experts............................................. 3.8
3.5 Elicitation Training............................................. 3.8
3.6 Presentation of Issues........................................... 3.10
3.7 Preparation and Discussion of Analyses....................... 3.11
3.8 Elicitation......................................................... 3.11
3.9 decomposition and Aggregation of Results..................... 3.12
3 .10 Review....... ....................................................... 3.13
3.11 Documentation...................................................... 3.13
4. ELICITATION MEETINGS.................................................... 4.1
5. CONTAINMENT LOADS ISSUES RESULTS --Part 1...........................5.1-1
5.1 Containment Loads Issue 1. Hydrogen
Phenomenon at Grand Gulf........ ............................... 5 ,1-1
5.2 Containment Loads Issue 2. Hydrogen Burn
at Vessel Breach at Sequoyah....................................5.2-1
5.3 Containment Loads Issue 3. BWR Reactor
Building Failure Due to Hydrogen Burns....................... 5.3-1
5.4 Containment Loads Issue 4. Grand Gulf
Containment Loads at Vessel Breach............................ 5.4-1
5.5 Containment Loads Issue 5. Pressure Increment
in the Sequoyah Containment at Vessel Breach................5.5-1
5.6 Containment Loads Issue 6. Loads at Vessel
Breach- -Surry.................,................................... 5.6-1
5.7 Containment Loads Issue 7. Pressure Increment
in the Zion Containment at Vessel Breach.....................5.7-1
6. MOLTEN CORE/CONTAINMENT INTERACTION ISSUES RESULTS--Part 2.....6.1-1
6.1 MCCI Isaue 1: Peach Bottom Drywell Shell Meltthrough......6.1-1
6.2 MCCI Issue 2: Grand Gulf Pedestal Erosion................... 6.2-1
5-1. Ignition Before Vessel Breach; RPV at
Low Pressure......................................................... 5.1-8
5-2. Ignition Before Vessel Breach; RPV at
High Pressure....................................................... 5.1-9
5-3. Ignition At Vessel Breach; RPV at
High Pressure....................................................... 5.1-10
5-4. Hydrogen Burn Completeness.........................................5.1-11
5-5. Deflagration Over Pressure; VJetwell; Low Steam................ 5.1-12
5-6. Deflagration Over Pressure; Wetwell; High Steam...............5.1-13
5-7. Frequency of Detonation--Low Steam............................... 5.1-14
5-8. Frequency of Detonation--High Steam.............................. 5.1-15
5-9. Loads From Hydrogen Detonation in Wetwell.......................5.1-16
A-l. Ignition Frequency Before Vessel Breach
Short-Term Station Blackout, High Pressure for Case 1....... 5.1-21
A-2, Ignition Frequency Before Vessel Breach
Short-Term Station Blackout, High Pressure for Case 2....... 5,1-21
A-3 Deflagration Overpressure (Wetwell)
Low Steam Case....................................................... 5.1-26
A-4 Frequency of Detonation at Grand Gulf
Low Steam Case....................................................... 5.1-26
A-5 Loads From Hydrogen Detonation in Grand
Gulf Wetwell..........................................................5.1.28
B-l Frequency of Ignition; 8% Mole Fraction Hydrogen--
Low Steam............................................................. 5.1-32
B-2 Frequency of Ignition; 12% Mole Fraction Hydrogen--
Low Steam............................................................. 5.1-32
B-3 Frequency of Ignition; 16% Mole Fraction Hydrogen--
Low Steam............................................................. 5.1-33
B-4 Frequency of Ignition; 20% Mole Fraction Hydrogen--
Low Steam............................................................. 5.1-33
B-5 Frequency of Ignition at Vessel Breach
8% Mole Fraction Hydrogen--Low Steam............................5.1-35
B-6 Frequency of Ignition at Vessel Breach
12% Mole Fraction Hydrogen--Low Steam...........................5.1-35
B-7 Frequency of Ignition at Vessel Breach
16% Mole Fraction Hydrogen.........................................5.1-36
B-8 Frequency of Ignition at Vessel Breach
16% tfole Fraction Hydrogen.........................................5.1-36
B-9 Completeness of Hydrogen Burn;
8% Mole Fraction Hydrogen.........................................5.1-39
B-10 Completeness of Hydrogen Burn;
12% Mole Fraction Hydrogen.........................................5.1-39
B-ll Completeness of Hydrogen Burn;
16% Mole Fraction Hydrogen........................ ............... 5.1-40
B-12 Frequency of Detonation; At Least
20% Mole Fraction Hydrogen............ ........... <.............. 5.1-41
B-13 Grand Gulf Detonation Loads. .......................................5.1-41
Containment Loads Issue 2
A-l Expert A's Decomposition Tree. Decomposition for
Hydrogen Burn........................................................5 . 2-12
B-l Expert B's Decomposition Tree. Percentages Under "Burn
Location" Indicate the Fraction of Zirconium Oxidation......5.2-21
C-l Expert C’s Decomposition Tree..................................... 5.2-27
Containment Loads Issue 3
3-1. Case 1 DWM.............................................................5.3-14
3-2. Case 1 OP.............................................................. 5.3-14
?> - 3 . Case 2 DWM.............................................................5.3-15
3-4 Case 2 OP.............................................................. 5.3-15
3- 5 Case 3 DWM.............................................................5.3-16
3-6 Case 3 OP..............................................................5. 3-16
3-7 Case 1: SB, High Pressure, High Steam............................5.3-18
3-8 Case 2: SB, High Pressure, Low Steam.............................5.3-18
3-9 Case 3: SB, Low Pressure, High or Low Steam.................... 5.3-19
3-10 Case 4: i'o SB, High Pressure, High Steam........................ 5.3-19
3-11 Case 5: No SB, High Pressure, Low Steam......................... 5.3-20
3-12 Case 6: No SB, Low Pressure, High or Low Steam................5.3-20
A-l Expert A's Decomposition Tree......................................5.3-23
A-2 Reactor Building Pressui^ Rise.....................................5.3-27
B-l Ignition of a Hydrogen-Nitrogen Jet (Without
Sodium) as a Function of Jet Temperature....................... 5.3-31
Containment Loads Issue 4
4-1 Grand Gulf Peak Dryvell/Wetwell Differential
Pressure at Vessel Breach. High RPV Pressure
With Wet Cavity.....................................................5.4-9
4-2. Grand Gulf Peak Drywell/Wetwell Differential
Pressure at Vessel Breach. Ixtw RPV Pressure
With Wet Cavity.....................................................5.4-10
4-3. Grand Gulf Peak Drywell/Wetwell Differential
Pressure at Vessel Breach. High RPV Pressure
With Dry Cavity.....................................................5.4-11
4-4. Grand Gulf Peak Containment Pressure at Vessel Breach.
High RPV Pressure With Wet or Dry Cavity.....................5.4-12
4-5. Grand Gulf Peak Containment Pressure at Vessel Breach.
Low RPV Pressure With Wet Cavity........................... .5.4-13
4-6. Grand Gulf Peak Pedestal Cavity Pressure at
Vessel Breach. High RPV Pressure With Wet Cavity............5.4-14
4-7. Grand Gulf Peak Pedestal Cavity Pressure at
Vessel Breach. Low RPV Pressure With Wet Cavity............. 5.4-15
4-8. Grand Gulf Peak Pedestal Cav\ty Pressure at
Vessel Breach. High RPV Pressure With Dry Cavity............5,4-16
A-l Containment Pressure Rise at Vessel Breach.....................5.4-20
A-2 Peak Static Drywell/Wetwell Pressure Differential;
Case 1: High Pressure, Wet Pedestal...........................5.4-22
A-3 Drywell Peak Static Pressure; Case 3*:
High Pressure, Dry Pedestal......................................5.4-23
A-4 Drywell Peak Static Pressure; Case 2*:
Low Pressure, Wet Pedestal.......................................5.4-24
A-5 Containment Pressure Rise; Cases 1 and 3*:
High Pressure Ejection............................................5.4-25
A-6 Maximum Pedestal Pressure; Case 3:
High Pressure, Wet Pedestal......................................5.4-26
A-7 Maximum Pedestal Pressure; Case 3*:
High Pressure, Dry Pedestal......................................5.4-27
A-8 Maximum Pedestal Pressure; Case 2*:
Low Pressure, Wet Pedestal.......................................5.4-28
Containment Loads Issue 5
5-1. Cavity Deeply Flooded; Above the Bottomhead
of the Vessel (Curves 1 & 2)................................... 5.5-6
5-2. RCS Low Pressure; Less Than 200 psia
(Curves 3 & 4 ) .................................................... 5.5-6
5-3. RCS Low Pressure; Less Than 200 psia
(Curves 5 & 6).................................................... 5.5-7
5-4 RCS Low Pressure; Less Than 200 psia
(Curves 7 & 8).................................................... 5.5-7
5-5 RCS Low Pressure; Less Than 200 psia
(Curves 9 & 10)................................................... 5.5-8
5-6 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 1, 2, & 3)............................................... 5.5-11
5-7 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 4, 5, & G)............................................... 5.5-1]
5-8 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 7, 8, & 9)............................................... 5.5-12
5-9 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 10, 11, & 12)............................................5.5-12
5-10 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 13, 14).....................................................5.5-13
5-11 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 15, 16, 17)................................................5.5-13
5-12 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 18, 19, 20)................................................5.5-14
5-13 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 21, 22, 23)................................................5.5-14
5-14 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 24, 25, 26)................................................ 5.5-15
5-15 RCS Intermediate Pressure; 500 to 1000 psia
(Curves 27, 28, 29)................................................5.5-15
5-16 RCS Intermediate Fressure; 500 to 1000 psia
(Curves 30, 31).................................................... 5.5-16
5-17 RCS High Pressure; 2000 to 2500 psia
(Curves 1, 2, 3)....................................................5.5-18
5-18 RCS High Pressure; 2000 to 2500 psia
(Curves 4, 5, 6)...................................................5.5-18
5-19 RCS High Pressure; 2000 to 2500 psia
(Curves 7, 8, 9)....................................................5.5-19
5-20 RCS High Pressure; 2000 to 2500 psia
(Curves 10, 11, 12)................................................5.5-19
Containment Loads Issue 7
7-1 Aggregate of Zion Containment Loading for Case 1..............5.7-10
7-2 Revised Aggregate of Zion Containment Loading
for Case 1............................................................ 5.7-14
MCCI Issue 1
C'l Cumulative Failure Probability of Drywell
vs. Time for Scenario A ...........................................6.1-23
C-2 Cumulative Failure Probability of Drywell
vs. Time for Scenario B ...........................................6.1-23
C-3 Cumulative Failure Probability of Drywell
vs. Time for Scenario C ...........................................6.1-24
6-1. Aggregation of MCCI Issue 2. Cumulative
Probability of Different Radial Erosion Depths
at Different Times.................................................6.2*9
B-l Case Structure for Grand Gulf Pedestal Erosion............... 6.2-17
B-2 Eroded Pedestal Geometry...........................................6.2-19
TABLES
1 NUREG-1150 Analysis Documentation................................xxiii
1.1 Containment Loads Issues Considered for Expert Judgment
Elicitation........................................................... 1.4
1.2 Molten Core/Containment Issues Considered for Expert
Judgment Elicitation................................................ 1.4
3-1 Issues Presented to the In-Vessel Panel......................... 3.4
3-2 Issues Presented to the Containment Loads Panel............... 3.5
3-3 Issues Presented to the Molten Core Containment./
Interaction Panel.................................................. 3.5
3-4 Issues Presented to the Structural Response Panel............ 3.6
3-5 Issues Presented to the Source Term Panel...................... 3.7
Containment Loads Issue 1
A-l. Hydrogen Ignition Half-Lives......................................5.1-20
A-2 Hydrogen Burn Completeness, ......................................5.1-25
A-3 Detonation Probability............................................. 5.1-25
A-4 Relative Likelihood Subsequent Peaks Are
Maximum Impulse......................................................5.1-27
B-l Distributions........................................................5.1-31
B-2 Selected Beta Distributions....................................... 5.1-34
B-3 Results for Adiabatic Burn Pressure............................. 5.1-37
B-4 Distribution of Burn Completeness................................5.1-38
xi
2-1 Distribution of Hydrogen in Containment;
Compartmental Fraction of Total Hydrogen Released
From the RCS.......................................................... 5.2-4
2-2 Mixing of Hydrogen into the Dome................................. 5.2-5
2-3 Distribution for Ignition Frequency in the
Ice Condenser........................................................ 5.2-5
2-4 Distribution for Ignition Frequency in the
Upper Plenum.......................................................... 5.2-6
2-5 Distribution for Ignition Frequency in the Dome............... 5.2-6
2-6 Distribution for DDT................................................ 5.2-7
2-7 Distribution for Detonation Impulse............................. 5.2-7
2-8 Burn Completion and Pressure Rise
Cases 1, 2, 3, and 4 ................................................ 5.2-8
A-l Distribution for Mixing of Upper Plenum
and Dome; [B] Distribution........................................ 5.2-13
A-2 Distribution for Mole Fraction in Unmixed
Upper Plenum; [D] Distribution....................................5.2-13
A-3 Distribution for Frequency of Ignition in the
Upper Plenum; [E 08] , [E12], [E 16] Distributions............. 5.2-13
A-4 Distribution for Frequency of Ignition in the
Ice Condenser Relative to Frequency in
Upper Plenum [C] Distribution.....................................5.2-15
A-5 Distribution for Frequency of Detonation in the
Ice Condenser or Upper Plenum, Given Ignition;
[F] Distribution.....................................................5.2-15
A-6 Distribution for Peak Pressure
Given Deflagration in Ice Condenser of Upper Plenum
[Gmf] Distribution.................................................. 5.2-15
A-7 Distribution for Impulse, Given Deconation;
[ H j Distribution.....................................................5.2-16
A-8 Distribution for Fraction of H2 Released
From RCS; [I] Distribution........................................ 5.2-16