Office for Nuclear Regulation

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Planned inspetion at Trawsfynydd Power Station

Executive summary

Purpose of intervention

This was a planned inspection of Magnox Ltd's Trawsfynydd power station, undertaken as part of the planned intervention strategy for the Sellafield, Decommissioning, Fuel and Waste (SDFW) Programme of the Office for Nuclear Regulation (ONR).

The work was carried out in line with the planned inspection programme contained in the Trawsfynydd Integrated Intervention Strategy (IIS).and Magnox Ltd Corporate IIS.

Interventions Carried Out by ONR

Planned Inspection of licence Condition 11

I carried out a System  Based Inspection (SBI) of the Trawsfynydd RPV; Cells; Vaults and Tanks; ILW packages. The purpose of this inspection was for ONR to examine whether the licensee's safety case claims in respect of this system important to safety had been adequately implemented.

The following activities were also undertaken:

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable - the safety system was judged to be adequate.

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

From the system based inspection I concluded that:

During the system inspection it became evident that various oversights and errors were present in the completion of the non-active commissioning documentation such that the outcome of commissioning did not appear consistent with declared strategy. A regulatory hold point has been agreed with Magnox Ltd, requiring further evidence to be provided to ONR confirming that that Magnox Ltd has complied with its arrangements and regulatory expectations before transitioning into active commissioning.

The LC11 inspection established that the Magnox Ltd proposals for implementation of revised emergency arrangements were well developed; however there was no robust evidence that key activities on the quality plans for implementation were complete. Consequently, while the arrangements appear reasonable and appropriate the completion of the key steps and evidence supporting these was not fully available. Based on the evidence presented there was not a sufficiently robust demonstration that Magnox Ltd is ready to make the transition and as such Magnox Ltd has been requested to consider the findings raised during the inspection and provide further evidence of meeting key requirements, before regulatory Approval can be provided.

The various liaison meetings undertaken provided useful updates on matters of regulatory interest.

Conclusion of Intervention

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


Magnox Cyf - Gorsaf Bŵer Trawsfynydd - Wedi'i Gynllunio

Pwrpas yr Ymyriad

Roedd hwn yn arolygiad wedi'i gynllunio o orsaf bŵer Trawsfynydd, a wnaed fel rhan o'r strategaeth ymyriadau wedi'u cynllunio ar gyfer Rhaglen Sellafield, Datgomisiynu, Tanwydd a Gwastraff (SDFW) y Swyddfa Dros Reoli Niwclear (ONR).

Cynhaliwyd y gwaith yn unol â'r rhaglen o arolygiadau wedi'u cynllunio a gynhwysir yn Strategaeth Ymyriadau Integredig Trawsfynydd (IIS) ac IIS Cofforaethol Magnox Cyf.

Ymyriadau a Wnaed gan ONR

Arolygiad wedi'i Gynllunio o Amod Trwydded 11

Fe wnes i gynnal Arolygiad Seiliedig ar System (SBI) o RPV Trawsfynydd; Celloedd; Fowtiau a Thanciau; pecynnau ILW. Pwrpas yr arolygiad hwn oedd i ONR archwilio a oedd honiadau achos diogelwch y trwyddedai ynghylch y system hon sy'n bwysig i ddiogelwch wedi'u gweithredu'n ddigonol.

Hefyd ymgymerwyd â'r gweithgareddau dilynol:

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

Ddim yn gymwys - dyfarnwyd bod y system ddiogelwch yn ddigonol.

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

O'r arolygiad seiliedig ar system fe wnes i gasglu:

Yn ystod yr arolygiad system daeth yn amlwg bod amryfuseddau a gwallau'n bresennol o ran cwblhau'r ddogfennaeth gomisiynu anweithredol fel nad oedd canlyniad y comisiynu'n ymddangos yn gyson â'r strategaeth oedd wedi'i datgan. Cytunwyd man dal rheoleiddiol gyda Magnox Cyf., yn mynnu bod tystiolaeth bellach yn cael ei darparu i ONR i gadarnhau bod Magnox Cyf. wedi cydymffurfio â'i drefniadau a disgwyliadau rheoleiddiol cyn pontio i gomisiynu gweithredol.

Fe wnaeth yr arolygiad LC11 sefydlu bod cynigion Magnox Cyf. ar gyfer gweithredu trefniadau argyfwng adolygedig wedi'u datblygu'n dda; fodd bynnag nid oedd unrhyw dystiolaeth gadarn bod gweithgareddau allweddol ar y cynlluniau ansawdd i'w gweithredu'n gyflawn. O ganlyniad, er bod y trefniadau'n ymddangos yn rhesymol a phriodol nid oedd y camau allweddol wedi'u cwblhau ac nid oedd tystiolaeth i gefnogi'r rhain ar gael. Yn seiliedig ar y dystiolaeth a gyflwynwyd nid oedd arddangosiad digon cadarn bod Magnox Cyf, yn barod i bontio ac oherwydd hynny gofynnwyd i Magnox Cyf. ystyried y canfyddiadau a godwyd yn ystod yr arolygiad a darparu tystiolaeth bellach o ddiwallu gofynion allweddol, cyn y gellir rhoi cymeradwyaeth reoleiddiol.

Fe wnaeth y cyfarfodydd cydgysylltu amrywiol a wnaed ddarparu diweddariadau defnyddiol ar faterion o ddiddordeb rheoleiddiol.

Casgliad yr Ymyriad

O'r wybodaeth a gafwyd yn ystod yr ymyriad hwn, credaf nad oedd unrhyw broblemau wedi'u nodi yr ystyriwyd eu bod yn effeithio'n niweidiol ar ddiogelwch niwclear.