iaea course on htr technology serpong, 19. … course on htr technology serpong, 19. -23.october...
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Safety Analysis - Introductory
HTR-MODULE
IAEA Course on HTR Technology
Serpong, 19. -23.October 2015
Dr. Gerd Brinkmann
BriVaTech Consulting
Andreas-Sapper-Str. 15
91334 Hemhofen
phone: +49 9195994747
mail: [email protected]
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 2
HTR-Module - Power Plant for Cogeneration of Electrical Power and Process Heat
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 3
Contents of Report I Introduction
II Table of contents
III List of tables
IV List of figures
V Abbreviations
VI Codes from identification system for power plants (KKS)
VII Graphical symbols used for mechanical, electrical and instrumentation and control equipment
1 Site
2 General design features of the HTR module power plant
3 Power plant
4 Radioactive materials and radiological protection
5 Power plant operation
6 Accident analysis
7 Quality assurance
8 Decommissioning
9 Waste management provisions
10 Guidelines and technical rules
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 4
Contents of Chapter 2 (SAR HTR Module)
> General design features of the HTR module power plant
> Introductory remarks
> Characteristic safety features
Barriers against release of radioactivity
Inherent safety
> Technical design features
Reactor
Nuclear steam supply system
Confinement envelope
Residual heat removal
Helium purification system
Fuel handling and storage
Emergency power supply
Reactor protection system
Remote shutdown station
Controlled area
> Nuclear classification and quality requirements
> Summary of design basis events
> Postulates and measures for in-plant events
> Postulates and measures for external events
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 5
Section 2.5 (SAR): Summary of Design Basis Events
> Listing of representative accidents by analogy with
„Accident Guidelines for Pressurized Water Reactors“
Assessment in report: approved. Listing of all design
basis events is complete, delimitation from hypothetical
realm correct.
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 6
Listing on Accidents
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 7
Event-Classification
> Class I:
Accidents with radiological relevance to the environment
> Class II:
Accidents without radiological relevance to the environment
> Class III:
Accidents with low risk
Event-Class III:
> Examples: Aircraft crash for explosion pressure wave
> Mitigation: Design of buildings and systems against
loads of the event
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 8
Events of Class III > Aircraft impact
> External shock waves from chemical reactions and as an event specific to the HTR-module
> Long-term failure of auxiliary power supply (> 15 h) and not
availability of emergency diesels.
Objectives met by design of:
reactor building
primary gas envelope (pressure vessel unit, steam piping, helium piping)
shut down system
cavity cooler
emergency control station
secondary cycle in reactor building
Measures (to be taken after 15 hours):
external feed of the cavity coolers
energy supply of the emergency control station
> Anticipated transients without scram (ATWS)
measures: interruption of the primary coolant flow
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 9
Events of Class I and II
In analogy with the accident guidelines
> RA: Radiological representative
> AS: Design of engineered safety systems or
countermeasures
> SI: Design of components and structures to ensure
stability or integrity
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 10
Accidents to be analyzed under the Aspect of „SI“
> Seismic events
objectives met by design of:
reactor building, electrical equipment building
primary gas envelope, shut down system
all intermediate cooling systems (cavity cooler)
all auxiliary cooling systems
emergency control station
secondary cycle in reactor building
emergency power supply, reactor safety system
> Life steam line rupture:
objectives met by design of:
mechanical stability of steam generator
integrity of the steam generator heat transfer tubes
> Rupture of a DN65 helium line:
objectives met by design of:
pressure build-up in the reactor building or
in the reactor auxiliary building
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 11
Accidents to be analysed under the Aspect of „AS“ (part1)
> Pressure loss in primary system DN65 leak without possibility of isolation met by:
Design of building depressurization system
Rupture of measuring line (DN10) met by:
Design of safe subatmospheric pressure system (filter line)
> Damage of steam generator heat transfer tubes Failure of one steam generator tube met by:
Design of measures for limitation of water ingress into the primary
system
> Reactivity accidents Withdrawel of all reflector rods met by:
Reactor core design.
Water ingress met by:
Reactor core design
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 12
Accidents to be analyzed under the Aspect of „AS“ (part 2)
> Disturbances in the main heat transfer system
Failure of auxiliary power supply and operation of emergency diesels
met by:
Design of intermediate cooling system.
Short-term failure of auxiliary power supply (< 2 hours) and non
availability of the emergency diesel met by:
Design of the batteries (instrumentation and control
equipment of the switchgear building), design of cavity coolers,
Long-term failure of auxiliary power supply (< 15 hours) and non-
availability of the emergency diesels met by:
Design of batteries (emergency control station),
design of cavity coolers
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 13
Events with radiological Relevance
> Leak in a line between RPV and isolation valve (representative to
leaks up to DN65 - leak cannot be isolated)
> Leak in an instrument line (representative to leaks up to DN10 -
leak cannot be isolated
> Leak in the Helium Purification System in the auxiliary Building
(representative to leaks up to DN65 - leak can be isolated)
> Leak of a vessel in the liquid waste system (representative to
systems containing radioactivity, but not primary coolant)
> Loss of integrity of a tube in the steam generator (representative
to systems not containing radioactivity)
Dr. Brinkmann, BriVaTech , IAEA Course on HTR Technology, Serpong, 19 -23. Oct. 2015 Page 14
Primary coolant,
leak can’t
be isolated
Primary coolant,
leak can
be isolated
Systems radio-
activity con-
taining but not
primary coolant
Small ball shutdown
elements feed system
Fuel charge and
discharge equipment
Helium supporting
system
Main steam
piping system
Feed water
piping system
Secured
cooling system
(Cavity cooler)
Fuel charge equipment Helium supporting systems
Helium purification system
Helium supporting
systems
Liquid
waste system
instrument
lines
Pressure
equalizing
system
Pressure relief
system
Tube
Bundle
Water/steam
systems
Helium supporting
systems
Reactor auxiliary building
Pressure vessel unit
Primary gas
envelope
Reactor
building
MK1
MK2a
MK2b
NNK
Systems
without
radioactivity
Turbine
building
Event Classification for HTR-Module Power Plants