development of safety case for the wolsong lilw disposal facility in korea
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Development of Safety Case for the Wolsong LILW disposal facility in KoreaTRANSCRIPT
Development of safety case for the Wolsong L&ILW disposal facility in Korea:
Geological Event
October 8, 2014
Jin Beak Park [email protected]
The 16th meeting of the Integration Group for the Safety Case (IGSC-16), 7-9 October 2014, NEA, France
CONTENTS
I. Status of Radioactive Waste Management in Korea
II. Wolsong Low and Intermediate-Level Radioactive Waste Disposal Facility
III. Development of Safety Case for the Wolsong L&ILW disposal facility
Ⅰ. Status of Radioactive Waste Management in Korea
I. Status of Radioactive Waste Management
□ Nuclear Industry in Korea
Daejeon Science Town : KAERI, KINS, KEPCO-NF KORAD R&D Center
23 Units (20,716MW)
In Operation
5 Units (6,600MW)
Under Const.
6 Units (8,600MW)
Planning
Yonggwang 1,2,3,4,5&6
Kori 1,2,3&4, ShinKori 1&2 ShinKori3&4(Under Const.)
Wolsong 1,2,3&4, ShinWolsong 1
ShinWolsong 2(Under Const.)
Ulchin 1,2,3,4,5&6 ShinUlchin 1&2(Under Const.)
KORAD HQ
WOLSONG SITE
I. Status of Radioactive Waste Management
□ Regulatory Structure in Korea (After Oct. 2011)
1. NSSC (Nuclear Safety And Security Commission) 2. AEC (Atomic Energy Committee 3. MEST (Ministry of Education, Science and Technology) 4. MOTIE (Ministry of Trade, Industry & Energy) 5. KINAC (Korea Institute of Nuclear nonproliferation and Control) 6. KINS (Korea Institute of Nuclear Safety) 7. KAERI (Korea Atomic Energy Research Institute) 8. KORAD (Korea Radioactive Waste Agency) 9. KHNP (Korea Hydro & Nuclear Power Co., Ltd.)
President
Prime Minister
MEST MOTIE
KAERI KORAD
AEC NSSC
KINS KINAC KHNP
1 2
3 4
6 7 8 9 5
Ⅱ. Wolsong Low and Intermediate-Level Radioactive Waste Disposal Facility
Ⅱ. Wolsong L&ILW Disposal Facility
□ Site Selection for LILW Disposal Facility
Painful Past Experiences
- A ‘Hot Potato’ for nearly two decades(1986-2005)
Overall Five Times by MOST / KAERI (1986 – 1996)
Four Times by MOCIE / KHNP (1997 – 2004)
Nine attempts from 1986 have all failed
Ⅱ. Wolsong L&ILW Disposal Facility
□ Site Selection for LILW Disposal Facility (2005)
Site Selection Committee (Mar. 2005)
- Open forums and discussions for the local residents
- The host area is to be selected through resident voting
Ⅱ. Wolsong L&ILW Disposal Facility
□ Site overview
Area - about 2,100,000 m²
Disposal capacity : 800,000 drums - 1st Stage 100,000 drums (2014) - 2nd Stage 250,000 drums (2018) - 3rd Stage on planning
Disposal Type
- 1st stage : Underground silo type
- 2nd stage: Shallow land disposal type
- 3rd stage : on planning
1st Stage Disposal Facility
East Sea
2nd Stage Disposal Facility
ShinWolsong NPP
Ⅱ. Wolsong L&ILW Disposal Facility
□ History of 1st Stage Disposal Facility Program
Site selection
(Nov. ‘05)
Approval of the implementation
plan
(Jul. ‘07)
Construction & Operation License/
Start to construction
(Aug. ‘08)
Completion of construct
(July ‘14)
Start to operate
(‘14)
Ⅱ. Wolsong L&ILW Disposal Facility
□ Operation of 1st stage disposal facility
Ⅱ. Wolsong L&ILW Disposal Facility
□ Closure of 1st stage disposal facility
Ⅱ. Wolsong L&ILW Disposal Facility
□ 1st Stage Disposal Facility (Construction completed)
<Construction tunnel> <Operational tunnel> <Waste loading tunnel>
<Disposal Silo> <Disposal Silo>
http://www.korad.or.kr
<Visiting Center>
Ⅱ. Wolsong L&ILW Disposal Facility
□ Schedule for the 2nd Stage Disposal Facility
Site Characterization
(Jan.‘12~Jul.‘15)
Detailed Design
(May’14~Dec.‘16)
Apply for the implementation plan approval
(Aug. ‘15)
Apply for the Construction &
Operational License
(Sep. ‘15)
Start to the Construction
(Jul. ‘16)
Construction Completion
(Dec. ‘18)
* Schedule can be changed depending on the Licensing period.
III. Development of Safety Case for the Wolsong L&ILW disposal facility
III. Development of Safety Case
□ Safety Approach
Safety Assessment
Risk analysis
Normal operation
Accidental scenario
Consequence analysis
Uncertainty analysis
Normal scenario Evolution scenario
Consequence analysis
Operational safety Post closure safety
Assessment Basis
Waste package characteristics
• Disposal waste • Inventory • Nuclide Analysis
Site characteristics • Geological structure • Hydrogeology • Underground water • Geochemistry • Environment
System description • Stability/Durability • Engineered barrier • Biosphere • Safety Function • Situation Analysis
Technological and scientific knowledge
Safety objectives Regulatory framework
International guidelines Safety strategy
Strategy& Context
Compliance Compliance of the safety level with the objective and decision making
Safety Principle
III. Development of Safety Case
□ Safety objectives
Comply with Safety Principle - Site selection, and disposal facility design, construction, operation and closure for
the protection of people and the environment against radiation risk after closure. 「NUCLEAR SAFETY ACT」Article 64, Issue3 and IAEA SSR-5(2011)
Meet the Performance objectives - It must be assured that radiation exposure dose rate and risk affecting to public
health should not be exceed the performance objectives in the future. NSSC Notice No.2012-55 Article 6(Period of Performance Evaluation)
Safety Optimization
- Achieved through an iterative process subject to the safety strategy
- Qualitative but embodied in a quantitative way
III. Development of Safety Case
□ Korean Standard for the Radiological Protection
NSSC Notice No. 2012-55 (Radiological Protection Criteria for Long-term Safety on Low and Intermediate Level Radioactive Waste Disposal)
Classification Performance Objectives Applicable Regulation
During Operation
Normal • Workers: 20 mSv/year • Public : 1.0 mSv/year
Korean Atomic Energy Act and its Enforcement
decree
Accident • Workers: 50 mSv • Public : 5.0 mSv
Suggested by KORAD
Post Closure
Normal • Performance Objective caused by natural phenomena • 0.1 mSv/year
NSSC Notice No. 2012-55 Accident
• Risk induced by un-controlled natural or man-made events
• 10-6/year
Human Intrusion
• After Institutional Control Period • 1.0 m Sv/year
□ International Guidelines Fundamental Safety Principle : IAEA SF-1(2006)
Disposal of Radioactive Waste: IAEA SSR-5(2011)
The Safety Case and Safety Assessment for the Disposal of Radioactive Waste: IAEA SSG-23(2012)
Safety Assessment for Facilities and Activities: IAEA GSR Part 4(2009)
III. Development of Safety Case
□ Safety Strategy
Iterative Process
(Optimization) Robustness
Demonstrability Multiple lines of evidence
Safety Strategy
Achievement of the safety objectives required to the entire disposal facility despite of a failure of safety function and related uncertainties
III. Development of Safety Case
□ Uncertainty Management : Construction phase
Sensitivity Analysis
IAEA ISAM FEPs
Disposal Facility Safety Function
Disposal Facility Components
Safety Function by Components
Uncertainty Analysis(Model/Data/Scenario)
Unresolved Issues on Model/Data
Screening
Model/Data Uncertainty
Scenario Uncertainty
Definition of Scenarios
R&D on Basic Field (Review & Development of necessity on the
additional Scenarios)
1. Identification
2. Characterization
3. Relevant for Safety
Need to eliminate or reduce
uncertainty?
4. Unresolved Issues Presents additional
Scenarios FEPs List to develop additional Scenarios
Post-closure SA (Normal/Altered/Intrusion)
5. Assessment Basis (R&D, etc)
Elaboration of Additional Scenarios
Uncertainty management plan
III. Development of Safety Case □ Safety Assessment Scenarios for 1st stage
Scenario Class Scenario Name Criteria
Reference Scenarios BS-1 Dose (mSv/yr)
BS-2 Dose (mSv/yr)
Alternative Scenarios ES-1 Risk (/yr)
ES-2 Risk (/yr)
Human Intrusion Scenarios
HS-1 Dose (mSv/yr) HS-2 Dose (mSv/yr)
HS-3 Dose (mSv/yr)
100
101
102
103
104
105
106
10-10
10-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
3.74E-3 mSv/yr
at 3600 yr
BS1 H-3
C-14
Ni-59
Nb-94
Tc-99
I-129
Total Alpha
Total Dose
Do
se (
mS
v/y
r)
Time after closure (yr)
□ BS-1 Reference Scenario
III. Development of Safety Case: Extreme geological event
□ ES-1 Alternative Scenario
□ ES-2 Alternative Scenario
Planning phase (2008) Conservatively, seismic event was assumed to be occurred just after the facility closure.
Event occurrence from Probabilistic Seismic Hazard Analysis (PSHA) to get the annual risk
Construction phase (2014) Probabilistic occurring of seismic events after the facility closure
Annual risk from the total expected exposures based on each probabilistic occurring
III. Development of Safety Case: Extreme geological event
□ Planning phase (2008)
□ Construction phase (2014)
100
101
102
103
104
105
106
10-20
10-19
10-18
10-17
10-16
10-15
10-14
10-13
10-12
10-11
10-10
10-9
10-8
10-7
10-6
6.04E-8 /yr at 1 yr ES-1A + ES-1B + ES2B
ES-1A
ES-1B
ES-2B
TOTAL
Ris
k (
yr-1
)
Time after closure (yr)
III. Development of Safety Case : Worst potential impact
□ HS-3 Human Intrusion Scenario (Well Scenario)
102
103
104
105
106
10-10
10-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
100
101
8.54E-1 mSv/yr
at 2040 yr
HS3-well 2 H-3
C-14
Ni-59
Nb-94
Tc-99
I-129
Total Alpha
Total Dose
Do
se (
mS
v/y
r)
Time after closure (yr)
Planning phase (2008) Conservative location setting along the ground water stream of flow
Conservative assumption with no dilution effects through the radionuclide transport
III. Development of Safety Case : Worst potential impact
<Groundwater flow modeling (2014)>
Construction phase (2014) Conservative location and depth of well setting by groundwater flow modeling (Particle
tracking)
Realistic assumption with dilution effect by groundwater flow modeling (Particle tracking)
□ HS-3 Human Intrusion Scenario (Well Scenario)
III. Development of Safety Case
□ Issues for Next Safety Case (2018)
Terminology Complex disposal facility
Co-location disposal facility
Anything better than these?
Application of regulatory criteria Is the current regulatory criteria can be
applied for site boundary including both disposal facilities or for each facility separately? (site limit vs. facility limit)
Additive radiological effect F(a)+F(b) vs. F(a+b)
NPPs in operation +
1st stage disposal facility after closure +
2nd stage disposal facility after closure +
(Temporary storage of SNF)
Representative exposure group How to prepare the representative
exposure group for complex disposal facility?
Thank you
for your attention!