Executive summary
Date(s) of inspection: September 2024
Aim of inspection
The aim of this inspection is to seek assurance that NRS Wylfa's arrangements for compliance with LC34 (Leakage and escape of radioactive material and radioactive waste) are adequate, and have been adequately implemented.
Subject(s) of inspection
- LC34 - Leakage and escape of radioactive material and radioactive waste - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
I carried out a LC34 compliance inspection at the NRS Ltd Wylfa site. LC34 concerns the control and containment of radioactive materials and radioactive wastes so far as is reasonably practicable to prevent their leakage or escape (including unintended release to land or groundwater), and the detection, notification, recording, investigation and reporting of any leakage or escape that occurs.. I utilised ONR guidance NS-INSP-GD-034 Revision 6 during the inspection. I reviewed the arrangements for this LC and their implementation, focussing on the DCICs (ductile cast iron containers) stored in DSC4 (dry store cell 4), and found them to be adequate. However, I was unable to find evidence that NRS had adequately considered the potential impact of the high-humidity storage conditions on the eventual acceptance of the DCICs into a GDF. I also found that the description of the storage conditions and their consideration within the relevant documentation, including the safety case, were not sufficiently clear, and have therefore raised a L4 issue.
Conclusion
I considered applicable legislation and relevant good practices including, but not limited to,
- Licence Condition 34(1) and (2)
- NS-INSP-GD-034 Issue 6 Licence Condition 34 Leakage and Escape of Radioactive Material and Radioactive Waste.
Based on the evidence sampled during this inspection, I judged there were no significant compliance shortfalls in NRS's arrangements, and therefore I assigned a GREEN inspection rating.
I also raised a L4 Issue related to the high humidity of the storage conditions of the DCICs (RI-12221).
Crynodeb gweithredol
Dyddiad(au) yr Arolygiad: 11/09/2024
Pwrpas yr Arolygiad
Nod yr arolygiad hwn yw ceisio sicrwydd fod trefniadau NRS Wylfa ar gyfer cydymffurfio ag LC34 (deunydd ymbelydrol a gwastraff ymbelydrol yn gollwng a dianc) yn ddigonol ac wedi'u gweithredu'n ddigonol.
Testun(au) yr Arolygiad
Roedd y gweithgareddau a ganlyn yn destun yr adolygiad hwn
- LC34 - Deunydd ymbelydrol a gwastraff ymbelydrol yn gollwng a dianc - GWYRDD
Canfyddiadau Allweddol
Cynhaliais arolygiad cydymffurfio ag LC34 yn safle Wylfa NRS Ltd. Mae LC34 yn ymwneud â rheoli ac ynysu deunyddiau ymbelydrol a gwastraff ymbelydrol cyn belled ag y bo'n ymarferol resymol i'w hatal rhag gollwng a dianc (gan gynnwys rhyddhau'n anfwriadol i dir neu ddŵr daear) a chanfod, cofnodi, archwilio unrhyw ddeunydd neu wastraff ymbelydrol sydd wedi gollwng neu ddianc a hysbysu neu adrodd amdanynt.Defnyddiais ganllawiau'r ONR Diwygiad 6 NS-INSP-GD-034 yn ystod yr Adolygiad.
Arolygais y trefniadau ar gyfer yr LC hwn a'u gweithrediad, gan ganolbwyntio ar y DCICs (cynwysyddion haearn bwrw hydrin) oedd wedi'u storio yn DSC4 (cell storio sych 4), a chael eu bod yn ddigonol. Fodd bynnag, ni lwyddais i ganfod tystiolaeth fod NRS wedi rhoi ystyriaeth ddigonol i effaith bosib yr amodau storio lleithder uchel ar dderbyn y DCICs i GDF (Cyfleuster Gwaredu Daearegol) yn y pen draw. Cefais, hefyd, nad oedd y disgrifiad o'r amodau storio a'u hystyriaeth yn y dogfennau perthnasol, gan gynnwys y cas diogelwch, yn ddigon clir ac, felly, rwyf wedi codi mater L4
Barnau a wnaed
Ystyriais ddeddfwriaeth berthnasol ac arferion da perthnasol gan gynnwys, ond heb fod yn gyfyngedig iddynt:
- Amod Trwyddedu 34(1) a (2)
- NS-INSP-GD-034Mater6AmodTrwyddedu 34 Deunydd Ymbelydrol a Gwastraff Ymbelydrol yn Gollwg a Dianc
Yn seiliedig ar y dystiolaeth a samplwyd yn ystod yr adolygiad hwn, barnais nad oedd diffygion cydymffurfio sylweddolol yn nhrefniadau'r NRS ac, felly, neulltuais sgôr arolygu GWYRDD.
Codais, hefyd, Fater L4 mewn perthynas â lleithder uchel amodau storio'r DCISs (RI-12221).