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					Current status of NPP C&I in the
        United Kingdom

21st Meeting of the Technical Working Group on Nuclear Power
  Plant Control and Instrumentation, 23-25 May 2007, Vienna


                      T P Smyth
            AMEC NNC, Knutsford, Cheshire, UK


                                                               1
Current status of NPP C&I in the United Kingdom

             Nuclear Power Plants in the UK

             Status of C&I at AGR nuclear plants
               Reactor Protection Systems
               Data Processing Systems
               Refuelling machines


             Status of C&I at PWR plant

             Simulators

             Status of regulatory environment affecting C&I

             Recommendations

TWG-NPPCI, May 2007, Vienna: UK status                         2
Nuclear Power Plants in the UK (1)
                                                          Start        Expected
Reactors                         Type     Unit capacity
                                                             operation   shutdown
Oldbury                          Magnox   2 x 217 MWe     1968       2008
Wylfa                            Magnox   2 x 490 MWe     1971       2010
Hinkley Point B                  AGR      2 x 610 MWe     1976       2011
Hunterston B                     AGR      2 x 595 MWe     1976       2011
Dungeness B                      AGR      2 x 555 MWe     1983       2018
Hartlepool                       AGR      2 x 605 MWe     1983       2014
Heysham 1                        AGR      2 x 575 MWe     1983       2014
Heysham 2                        AGR      2 x 625 MWe     1988       2023
Torness                          AGR      2 x 625 MWe     1988       2023
Sizewell B                       PWR      1188 MWe        1995       2035
Total (19)‫‏‬                               10 982 MWe

TWG-NPPCI, May 2007, Vienna: UK status                                          3
Nuclear Power Plants in the UK (2)‫‏‬
       Electricity sources
            20% nuclear
            37% gas
            34% coal
       Need to plan for energy replacement
            7 plants will close in next 11 years
            14 reactors
            7294 MWe
            13% of electricity sources
            North Sea oil and gas will be limited in future
       23 May 2007
            Government announces 20 week consultation process
            Government wants to take decision this year
            No public money


TWG-NPPCI, May 2007, Vienna: UK status                           4
AGR : Reactor Protection Systems (1)‫‏‬




TWG-NPPCI, May 2007, Vienna: UK status   5
 AGR : Reactor Protection Systems (2)‫‏‬
        Obsolescence of equipment
          Difficulty in obtaining spares

          Repairs

          Replacement

        Analogue trip units
          Neoprene degradation

          New equipment

        Majority of protection parameters have been addressed




TWG-NPPCI, May 2007, Vienna: UK status                           6
AGR : Reactor Protection Systems (3)‫‏‬
   Neoprene insulation degradation
       Magnox Oldbury power station
       Degradation with age
            Perishing
            Sweating
            Hygroscopic
            Becomes conductive - resistance < 1 MΏ
       Stray currents in sensitive circuits
            Thermocouple amplifiers




TWG-NPPCI, May 2007, Vienna: UK status                7
AGR : Reactor Protection Systems (4)‫‏‬
   Neoprene insulation degradation‫‏‬




TWG-NPPCI, May 2007, Vienna: UK status   8
AGR : Reactor Protection Systems (5)‫‏‬
   Neoprene insulation degradation




TWG-NPPCI, May 2007, Vienna: UK status   9
AGR : Reactor Protection Systems (6)‫‏‬
   Neoprene insulation degradation
       Survey of all safety equipment
            Presence of neoprene
            State of neoprene
            Circuit function
       Replacement equipment at older stations
            Obsolescent anyway
       Repairs at newer stations
            Heysham 2 / Torness
       4 years work, 2 more years to finalise all equipment



TWG-NPPCI, May 2007, Vienna: UK status                         10
AGR : Reactor Protection Systems (7)‫‏‬
   Neutron Flux measurement systems
       AGR detectors located in core at 8 locations
            High temperatures
       Detector spares
            Wide range detector – integral cable
            Manufacturing spares – re-establishing production processes
            Currently a batch of 10 in progress
       Electronic units
            Neoprene
            Complete refit
            Repairs at Heysham 2 / Torness


TWG-NPPCI, May 2007, Vienna: UK status                                     11
AGR : Reactor Protection Systems (8)‫‏‬
   Diverse Guardline upgrade
       Hinkley B / Hunterston B / Dungeness
            Driven by licensing basis for nuclear power plants
            Large subset of Main Guardline parameters duplicated
            From 1995 to 2000
       Heysham 2 / Torness had diverse guardlines from the
        outset.
       Hartlepool / Heysham 1 were judged to have adequate
        diversity in protection systems




TWG-NPPCI, May 2007, Vienna: UK status                              12
AGR : Data Processing Systems
       Safety claims on equipment
            Some reactor control functions
            Some alarms
       Hinkley Point B
            New DPS installed (1999)‫‏‬
       Dungeness B
            New DPS being installed
            Control / equipment protection functions segregated
       Other AGR's
            Stabilization of equipment
                Adequate spares provision / hardware support.
                Improved air conditioning
                Limited re-manufacturing (optical transceiver boards)‫‏‬
TWG-NPPCI, May 2007, Vienna: UK status                                    13
AGR : Refuelling Machines (1)‫‏‬




TWG-NPPCI, May 2007, Vienna: UK status   14
AGR : Refuelling Machines (2)‫‏‬




TWG-NPPCI, May 2007, Vienna: UK status   15
AGR : Refuelling Machines (3)‫‏‬
       Online refuelling
            Stringent safety requirements
       Equipment obsolescence
            Key focus at present
       Heysham 2 / Torness
            Replacement of Reypac controllers with Siemens S7
                I/O replaced, emulates original equipment
                Reypac controller replacement in progress
                Software reverse engineered and ported
                Safety functions partitioned
       Safety standards
            Modern standards considered when replacing equipment

TWG-NPPCI, May 2007, Vienna: UK status                              16
PWR : Principal C&I Systems (1)‫‏‬




TWG-NPPCI, May 2007, Vienna: UK status   17
PWR : Principal C&I Systems (2)‫‏‬
       Equipment Life cycle management
            Review of equipment status
            Review of spares holdings
            Participation of OEM (Westinghouse)‫‏‬
       HICS
            Optical transceiver units obsolete
            New units re-engineered by Westinghouse
            Adequate spares manufactured




TWG-NPPCI, May 2007, Vienna: UK status                 18
Simulators
       Sizewell B
            On site
            Replaced in 2003
            Duplicate DPS
                Can be modified at the same time as the main DPS
                WANO recommendation
       AGR's
            Goal was to establish a simulator at each site
            Hartlepool - new simulator
            Heysham 2 / Torness
                Upgraded to increase fidelity
                WANO recommendation


TWG-NPPCI, May 2007, Vienna: UK status                              19
Regulatory Environment (1)‫‏‬
       Standards hierarchy
            NII SAPS
            IAEA standards
            IEC standards
                IEC 61226
       PSA based assessment
            Target 10-7 / year
       Limit of reliability claims for software based systems
            Assume 1 demand / year
            10-4/demand
            Require diverse protection to make up 10-3/demand




TWG-NPPCI, May 2007, Vienna: UK status                           20
Regulatory Environment (2)‫‏‬
       Application to Sizewell B
            Primary Protection System
                Four channels, 2 out of 4 tripping
                Software based
                Production excellence
                  IEC 61880
                Independent confidence building
                  Extensive testing
                  Independent code safety assessment
            Secondary Protection System
                Four channels, 2 out of 4 tripping
                Protection for frequent faults
                Laddic – magnetic amplifiers
                Diverse technology




TWG-NPPCI, May 2007, Vienna: UK status                  21
Regulatory Environment (3)‫‏‬
   New build
       In general, same regulatory requirements as Sizewell B
            Diversity requirements in reactor protection systems
            Possibly lower protection system targets
                Passively safe systems will make fewer demands
       Commercial Off the Shelf systems
            Assessment of evidence
       Smart Instruments
            Regulator considering application to nuclear facilities
            Assessment of evidence




TWG-NPPCI, May 2007, Vienna: UK status                                 22
Recommendations
   IAEA topics
       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




TWG-NPPCI, May 2007, Vienna: UK status                           23

				
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