trawsfynydd rpv inspections - institute of asset management presentation 2013
DESCRIPTION
A presentation given at the 2013 Institute of Asset Management Conference at St Pauls, London. Details remote access techniques and some of the challenges experienced during the 2012/13 inspection of the Trawsfynydd reactor pressure vessels.TRANSCRIPT
Site or Business areaRPV inspections - Trawsfynydd
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Introduction
Lonely Planet (2013). Map of Snowdonia National Park, Available at: http://www.lonelyplanet.com/maps/europe/wales/snowdonia-national-park/, Accessed 2nd September, 2013
Maplandia.com (2005). Trawsfynydd Map, Available at: http://www.maplandia.com/united-kingdom/wales/wales/gwynedd/trawsfynydd/#map, Accessed 17th May, 2013.
Trappe, R (2013). Photo of Trawsfynydd.
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o To provide a comparison of the condition of the two reactor vessels in sufficient detail to allow detailed analysis of any degradation since the last inspection.
o To provide sufficient detail and records to establish a baseline to allow future comparisons to be made.
o To provide sufficient information for a technical review to consider the results of the inspection work, previous corrosion coupon and environmental conditions analysis, against predictions and assumptions in the numerous reports upon which the safety case is based.
o To provide sufficient inspection and analysis to underpin the long term reactor buildings safety case.
Requirements
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Scope
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Chargeface access
o Via shortened SCAs
o 4 locations for core restraint
o 5 locations for sub-diagrid
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Vessel viewing holes
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Inspection findings – reactor void
No significant corrosion issues
Cladding detached from R2 cold gas ducts
Displaced floor plates
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Detached cladding to R2
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Displaced floor plates
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R1 inspection
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Internal inspection
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Short arm manipulator
Used to deploy cameras and light bomb
Manufactured by BICO Ltd at Beaumaris
Mock-up and trials at off-site industrial facility
Successfully deployed in November 2012
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Internal inspection findingso No significant corrosion issues.
o Opportunity taken to remove SCA ball-lock mechanisms.
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R2 vessel internal inspection
Core restraint
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R2 vessel internal inspection
Below diagrid
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R1 vessel internal inspection
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Basement access
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Survey of R2 reactor voido Access created during
previous entries.
o Significant asbestos issues.
o Cutting of SCA duct would be required for R1 access.
o Mock-up of SCA at PFS for trialling access and cutting of SCA duct.
o Try to determine cause of displaced floor plates.
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Pantograph survey to R2
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Survey below reactor void floor to R2
o Survey previously completed to R2 in 1997o Determine cause of displaced floor plates
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Debris duct surveys
o Survey of R2 completed in 2007
o Flange plate to R1 removed and inspected in April 2012
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Cold gas ducts
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Survey of R1 reactor void
Access to reactor void will be technically difficult and subject to radiological assessment
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Output of the inspections will be two reports:
o Survey report covering all of the inspections
o Technical assessment report of the survey including other environmental monitoring and corrosion data
The reports will be used to support the long term reactor building safety cases and the future inspection regime.
Outputs of inspection
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Conclusions
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Survey to R1 – cct 6 to basement
o Cold gas duct
o Under floor plates
o R1 debris duct scope is complete
o Access to reactor void will be technically difficult and subject to dose assessments
Any questions?Acknowledgements:
Kevin Lewis, Magnox LtdRob Evans, Magnox LtdGeoff Owen, Magnox LtdThe Magnox Remote Ops team of Graham, Dean, John and FingersGron Jones, BICO Ltd