Office for Nuclear Regulation

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Wylfa, Examination, Inspection, Maintenance and Testing of Nuclear Lifting Operations and Lifting Arrangements

Executive summary

Purpose of intervention

The purpose of this intervention was to explore the Examination, Inspection, Maintenance and Testing (EIMT) arrangements in place on the Wylfa nuclear licensed site and to judge the adequacy of the measures currently in place to meet the requirements of the safety case.  A particular focus of the intervention was to judge the adequacy of the Nuclear Lifting Operations and Lifting Arrangements associated with fuel movements.

The intervention was motivated through a need to inform the assessment of the Wylfa post generation defueling safety case (PGDSC), currently under consideration by ONR.  The assessment forms part of ONR's regulatory judgement towards a decision regarding the issuing of a Licence Instrument permissioning Magnox Ltd - Wylfa to commence defueling reactors 1 and 2 following cessation of power generation in December 2015.

Interventions Carried Out by ONR

An inspection of the EIMT arrangements at the Magnox Wylfa site was undertaken, in addition examinations were also undertaken investigating the fatigue tolerance of lifting equipment important to the planned defueling procedures.

A reactive inspection also was undertaken in response to a shortfall in lifting plan development.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

Through sampling EIMT documentation and related SQEP records I was content that adequate arrangements are in place to ensure that the continuing safety function of the lifting machines through the licensees EIMT arrangements is adequately managed.

The reactive examination of lifting plans and implementation of SQEP strategy for lifting arrangements concluded that adequate arrangements were in place ensuring adequately trained individuals are undertaking lifting operations to approved lifting plans.

The examination of fatigue reports and subsequent testing of assumptions now Wylfa has ceased generation has provided adequate substantiation that the relevant lifting equipment for defuel will deliver its safety function for the duration of defuel.

Conclusion of Intervention

From the information obtained and evidence gathered during this intervention, I do not believe there are any matters identified that have a significant negative effect on the nuclear safety on the Wylfa power station at this time.  The licensee’s EIMT arrangements examined were considered to be of an adequate standard.


Crynodeb gweithredol

Diben yr Ymyrraeth

Diben yr ymyrraeth hon oedd archwilio trefniadau Archwilio, Arolygu, Cynnal a Chadw a Phrofi (EIMT) sydd ar waith yn safle trwyddedig niwclear Wylfa ac i farnu digonolrwydd y mesurau sydd ar waith ar hyn o bryd i fodloni gofynion yr achos diogelwch.  Ffocws penodol yn yr ymyrraeth oedd barnu digonolrwydd Gweithrediadau Codi Niwclear a Threfniadau Codi sy'n gysylltiedig gyda symudiadau tanwydd.

Roedd yr ymyrraeth wedi ei ysgogi trwy angen i hysbysu'r asesiad o achos diogelwch gwagio tanwydd yn dilyn cynhyrchu (PGDSC) Wylfa, sydd ar hyn o bryd dan ystyriaeth gan yr ONR.  Mae'r asesiad yn rhan o ddyfarniad yr ONR tuag at benderfyniad parthed cyhoeddi caniatâd Offerynnau Trwyddedu Magnox Ltd - Wylfa i gychwyn tynnu tanwydd o adweithyddion 1 a 2 yn dilyn terfynu cynhyrchu pŵer yn Rhagfyr 2015.

Ymyraethau a Gyflawnwyd gan yr ONR

Cyflawnwyd archwiliad o drefniadau EIMT yn safle Wylfa Magnox, yn ogystal cynhaliwyd archwiliadau hefyd i ymchwilio i oddefiant lludded offer codi sy'n bwysig i weithdrefnau gwagio tanwydd arfaethedig.

Cynhaliwyd archwiliad adweithiol hefyd mewn ymateb i ddiffyg yn natblygiad y cynllun codi.

Esboniad o’r Dyfarniad os Nad oedd y System Ddiogelwch wedi cael ei Barnu yn Ddigonol.

Ddim yn berthnasol.

Casgliadau Allweddol, Barnau’r Arolygydd a Rhesymau dros Wneud Dyfarniadau

Trwy samplu dogfennaeth EIMT a chofnodion SQEP cysylltiedig, roeddwn yn fodlon fod yna drefniadau digonol ar waith i sicrhau fod swyddogaeth ddiogelwch parhaus y peiriannau codi hyd at drefniadau EIMT y trwyddedai wedi eu rheoli'n ddigonol.

Casglodd yr archwiliad adweithiol o gynlluniau codi a gweithrediad y strategaeth SQEP ar gyfer trefniadau codi fod trefniadau digonol ar waith i sicrhau fod unigolion gyda hyfforddiant digonol yn cyflawni gweithrediadau codi i gynlluniau codi cymeradwy.

Mae'r archwiliad o adroddiadau lludded a phrofion dilynol o dybiaethau nawr fod Wylfa wedi rhoi'r gorau i gynhyrchi wedi darparu cadarnhad digonol y bydd yr offer codi perthnasol ar gyfer gwagio tanwydd yn cyflawni ei swyddogaeth diogelwch trwy gydol gwagio tanwydd.

Casgliad yr Ymyrraeth

O'r wybodaeth a gafwyd a'r dystiolaeth a gasglwyd yn ystod yr ymyrraeth hon, nid wyf yn credu bod yna unrhyw faterion a nodwyd sy'n cael effaith negyddol arwyddocaol ar ddiogelwch niwclear yng ngorsaf bŵer Wylfa ar hyn o bryd.  Ystyriwyd trefniadau EIMT y trwyddedai a archwiliwyd i fod o safon ddigonol.