Office for Nuclear Regulation

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Site Inspection - Wylfa

Executive summary

Purpose of Intervention

This was a planned inspection at Magnox Ltd's (ML) Wylfa site, undertaken as part of the Decommissioning, Fuel and Waste (DFW) Programme strategy and planned inspection programme for 2017/18.

Interventions Carried Out by ONR

Planned Licence Condition (LC) 22 Inspection (Modification or experiment on existing plant) and reactive unplanned inspection under LC36 (Organisational capability).

Additional meetings were undertaken to review and update the site inspector on the following matters:

Explanation of Judgement if Safety System Not Judged to be Adequate

No safety system based inspections were undertaken during this intervention.

Key Findings, Inspector's Opinions and Reasons for Judgements Made

Until recently the site Licence Condition 22 arrangements implemented at Wylfa for compliance with this licence condition were mature. As part of the site's progression through defuelling towards care and maintenance preparations the site has implemented revised arrangements consistent with the rest of the Magnox decommissioning sites. Consequently current modifications are mainly progressing under the arrangements in force during generation. A sample of recent modifications was selected for inspection including the first modification under the new arrangements being implemented at Wylfa. From the inspections undertaken I conclude that there are no significant shortfalls in delivery of safety. A minor failure to adequately implement changes to group 2 alarms was identified and Magnox Ltd agreed to ensure this matter is addressed promptly (Section 2.1.3). Consequently I have assigned an inspection rating of green to Licence Condition 22.

In response to discussions with an ONR Leadership and Management for Safety Inspector a Licence Condition 36 inspection was undertaken on the implementation of resource changes during defuelling of the Wylfa site. Due to difficulties experienced during defuelling Magnox Ltd intends to revise the structure at Wylfa and maintain higher levels of staff than originally proposed. Consequently, Magnox Ltd intends to terminate the implementation of original planned changes to the organisational capability, and is proposing to produce a new justification to underpin resource requirements for defuelling to ensure that the Magnox Ltd meet reprocessing demands at Sellafield.

Additional meetings confirmed that Magnox Ltd is continuing to maintain focus on competing demands and seeking opportunities to ensure legal obligations are delivered in a proportionate manner.

Conclusion of Intervention

From the information obtained and evidence gathered during this intervention, I believe there were no issues identified that were considered to adversely affect nuclear safety.


Pwrpas yr Ymyrraeth

Roedd hwn yn arolygiad cynlluniedig o safle Wylfa Magnox Cyf., a wnaed fel rhan o'r rhaglen strategaeth ac arolygiad cynlluniedig y Rhaglen Datgomisiynu, Tanwydd a Gwastraff (DFW) ar gyfer 2017/18.

Ymyriadau a Wnaed gan ONR

Gwnaed Arolygiad Cynlluniedig Amod Trwydded (LC) 22 (Addasiad neu arbrawf ar offer presennol) ac arolygiad adweithiol heb ei gynllunio o dan LC36 (Galluogrwydd sefydliadol).

Ymgymerwyd â chyfarfodydd ychwanegol i adolygu a diweddaru'r arolygydd safle ar y materion dilynol:

Esboniad o'r Dyfarniad os Na Ddyfernir bod y System Ddiogelwch yn Ddigonol

Ni wnaed unrhyw arolygiadau seiliedig ar system ddiogelwch yn ystod yr ymyrraeth hon.

Canfyddiadau allweddol, Barnau'r Arolygydd a Rhesymau am Ddyfarniadau a Wnaed

Tan yn ddiweddar roedd y trefniadau safle ar gyfer Amod Trwydded 22 a weithredwyd yn Wylfa i gydymffurfio â'r amod trwydded hwn yn aeddfed. Fel rhan o gynnydd y safle trwy dathlwn tuag at baratoadau ar gyfer gofal a chynnal a chadw mae'r safle wedi gweithredu trefniadau adolygedig sy'n gyson â gweddill safleoedd datgomisiynu Magnox. O ganlyniad mae addasiadau cyfredol yn cynyddu'n bennaf o dan y trefniadau mewn grym yn ystod y cyfnod cynhyrchu. Dewiswyd sampl o addasiadau diweddar i'w harolygu gan gynnwys yr addasiad cyntaf o dan y trefniadau newydd yn cael eu gweithredu yn Wylfa. O'r arolygiadau a wnaed rwyf yn casglu nad oes unrhyw ddiffygion arwyddocaol ynghylch cyflenwi diogelwch. Nodwyd methiant mân i weithredu newidiadau i larymau grŵp 2 yn ddigonol ac fe wnaeth Magnox Cyf. gytuno i sicrhau y trafodir y mater hwn yn gyflym (Adran 2.1.3). O ganlyniad rwyf wedi rhoi gradd arolygiad o wyrdd i Amod Trwydded 22.

Mewn ymateb i drafodaethau ag Arolygydd Arweinyddiaeth a Rheolaeth er Diogelwch ONR gwnaed arolygiad Amod Trwydded 36 ar weithredu newidiadau adnoddau yn ystod o broses o ddatlenwi'r safle Wylfa. Oherwydd anawsterau a brofwyd yn ystod y dathlwn mae Magnox Cyf, yn bwriadu adolygu'r strwythur yn Wylfa a chynnal lefelau uwch o staff nag a ragwelwyd yn wreiddiol. O ganlyniad, mae Magnox Cyf. yn bwriadu terfynu'r broses o weithredu newidiadau cynlluniedig gwreiddiol i'r galluogrwydd sefydliadol, ac mae'n argymell cynhyrchu cyfiawnhad newydd i fod yn sylfaen i ofynion ynghylch adnoddau ar gyfer datlenwi er mwyn sicrhau bod Magnox Cyf. yn diwallu galwadau ailbrosesu yn Sellafield.

Fe wnaeth cyfarfodydd ychwanegol gadarnhau bod Magnox Cyf. yn dal i gynnal ffocws ar alwadau sy'n cystadlu ac yn ceisio cyfleoedd i sicrhau y cyflenwir goblygiadau cyfreithiol mewn modd cymesur.

Casgliad yr Ymyrraeth

O'r wybodaeth a gafwyd a'r dystiolaeth a gasglwyd yn ystod yr ymyrraeth hon, credaf na nodwyd unrhyw broblemau yr ystyriwyd eu bod yn effeithio'n niweidiol ar ddiogelwch niwclear.