Transcript Current status of NPP I&C in the United Kingdom 22nd Meeting of the Technical Working Group on Nuclear Power Plant Instrumentation and Control,

Current status of NPP I&C in the
United Kingdom
22nd Meeting of the Technical Working Group on Nuclear Power
Plant Instrumentation and Control, 20-22 May 2009, Vienna
T P Smyth
AMEC, Knutsford, Cheshire, UK
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Current status of NPP I&C in the United Kingdom
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Nuclear Power Plants in the UK
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Status of I&C at nuclear plants
 Reactor Protection Systems
 Data Processing Systems
 Refuelling machines
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Status of regulatory environment affecting I&C
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Recommendations
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Nuclear Power Plants in the UK (1)
Reactors
Type
Unit capacity
Start
Expected
operation
shutdown
Oldbury
Magnox
2 x 217 MWe
1968
2010
Wylfa
Magnox
2 x 490 MWe
1971
2010
Hinkley Point B
AGR
2 x 610 MWe
1976
2016
Hunterston B
AGR
2 x 605 MWe
1976
2016
Dungeness B
AGR
2 x 545 MWe
1983
2018
Hartlepool
AGR
2 x 595 MWe
1984
2014
Heysham 1
AGR
2 x 615 MWe
1985
2014
Heysham 2
AGR
2 x 615 MWe
1988
2023
Torness
AGR
2 x 625 MWe
1988
2023
Sizewell B
PWR
1 x 1196 MWe
1995
2035
Total (19)
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11 035 MWe
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Nuclear Power Plants in the UK (2)
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Electricity sources
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Need to plan for energy replacement
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19% nuclear
36% gas
38% coal
7 plants will close in next 9 years
14 reactors
7359 MWe
13% of electricity sources
North Sea oil and gas will be limited in future
New build
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Generic Design Assessment (AP1000, EPR)
Target completion of GDAs June 2011
Sites identified
http://www.hse.gov.uk/newreactors/
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AGR : Reactor Protection Systems (1)
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Neoprene insulation degradation
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Magnox Oldbury power station
Degradation with age
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Perishing
Sweating
Hygroscopic
Becomes conductive - resistance < 1 MΏ
Stray currents in sensitive circuits
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Thermocouple amplifiers
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AGR : Reactor Protection Systems (2)
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Neoprene insulation degradation
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AGR : Reactor Protection Systems (3)
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Neoprene insulation degradation
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AGR : Reactor Protection Systems (4)
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Neoprene insulation degradation
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Survey of all safety equipment
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Replacement equipment at older stations
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Obsolescent anyway
Repairs at newer stations
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Presence of neoprene
State of neoprene
Circuit function
Heysham 2 / Torness
6 years work, 1 more year to finalise all equipment
Prioritised by susceptibility
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AGR : Reactor Protection Systems (5)
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Neutron Flux measurement systems
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AGR detectors located in core at 8 locations
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Detector spares
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High temperatures
Wide range detector – integral cable
Manufacturing spares – re-establishing production processes
Currently a batch of 10 in progress
Electronic units
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Neoprene
Repairs at Heysham 2 / Torness
Replacement at other stations
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AGR : Data Processing Systems
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Safety claims on equipment
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Hinkley Point B
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New DPS installed (1999)
Dungeness B
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Some reactor control functions
Some alarms
New DPS being installed
Control / equipment protection functions segregated
Ready for works testing
Other AGR's
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Stabilization of equipment
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Adequate spares provision / hardware support.
Improved air conditioning
Heysham 2: specification phase
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AGR : Refuelling Machines
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Online refuelling
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Equipment obsolescence
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Stringent safety requirements
Key focus at present
Heysham 2 / Torness
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Replacement of Reypac controllers with Siemens S7
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I/O replaced, emulates original equipment
Reypac controller replacement
Software reverse engineered and ported
Safety functions partitioned
Successful implementation, scope of replacement expanded.
Safety standards
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Modern standards considered when replacing equipment
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Regulatory Environment (1)
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Standards hierarchy
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NII SAPs and TAGs (http://www.hse.gov.uk/nuclear)
IAEA standards
IEC standards
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Modern standards reviews
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Design, Operation and Maintenance
Part of Periodic Safety Reviews
PSA based assessment
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IEC 61226
Target 10-7 / year
Limit of reliability claims for software based systems
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Assume 1 demand / year
10-4/demand
Require diverse protection to make up 10-3/demand
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Regulatory Environment (2)
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Application to Sizewell B
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Primary Protection System
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Four channels, 2 out of 4 tripping
Software based
Production excellence
 IEC 60880
Independent confidence building
 Extensive testing
 Independent code safety assessment
Secondary Protection System
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Four channels, 2 out of 4 tripping
Protection for frequent faults
Laddic – magnetic amplifiers
Diverse technology
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Regulatory Environment (3)
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New build
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In general, same regulatory requirements as Sizewell B
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Diversity requirements in reactor protection systems
Possibly less onerous protection system targets
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Passively safe systems will make fewer demands
Smart Instruments
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Regulator considering application to nuclear facilities
Assessment of evidence
Plant owner collaboration
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Shared qualification and licensing assessments
SIL1
No fieldbus
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Recommendations
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IAEA topics
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Estimating and extending life of I&C equipment to
address ageing and obsolescence
Supporting the evaluation, acceptance and licensing of
digital I&C system
Lessons learned from I&C project implementation and
guidance for modernisation and new plant project
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