Office for Nuclear Regulation

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Site Inspection - Wylfa

Executive summary

Purpose of Intervention

This planned inspection of Magnox Ltd’s Wylfa power station was undertaken as part of a series of planned inspections for 2017/18 in pursuit of the strategy for the Decommissioning, Fuel and Waste (DFW) Sub-division.

Interventions Carried Out by ONR

Planned inspections of Licence Conditions (LCs) 32, 33 and 34 were undertaken.

Additional meetings were undertaken to review 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

LC32 inspection of current radioactive waste storage areas confirmed that accumulation of radioactive waste was well managed and wherever practical minimised. Labelling of material was of a good standard and only few minor observations were made that related to ensuring consistency of standards being applied to majority of waste accumulated. Relevant good practice has been generally met in all areas and the waste team are actively progressing reductions of potential accumulations to ensure that risks remain reduced ALARP.

LC33 inspection confirmed that Magnox Ltd has mature arrangements and procedures for undertaking disposals that meet environmental legislation. Responses to observations to improve arrangements to align with ONR requirements for response to potential formal directions have been addressed and compliance meets regulatory expectations.

In support of the LC34 inspection Magnox Ltd provided a summary of incidents during the past year that involved potential leakage and escape of radioactive material. Inspection of the licensee’s response to these incidents confirmed that there are very few instances of leakage and escape and those identified constituted minor leakages of low radiological significance. Responses to the events have been proportionate and appropriately targeted by the licensee. Inspection of the Active Effluent Treatment Plant (AETP) confirms that asset care/management is delivered to a good standard.

Additional meetings confirmed that Magnox Ltd is continuing to maintain focus on competing demands and seeking to ensure legal obligations continue to be met.

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 archwiliad a gynlluniwyd o orsaf bŵer Magnox Cyf Wylfa, a gynhaliwyd fel rhan o gyfres o archwiliadau ar gyfer 2017/18 i ddilyn hynt y strategaeth ar gyfer Is-adran Digomisiynu, Tanwydd a Gwastraff (DFW).

Ymyriadau a Gynhaliwyd gan Y Swyddfa dros Reoli Niwclear (ONR)

Cynhaliwyd archwiliadau a gynlluniwyd o Amodau Trwydded (LCs) 32, 33 a 34.

Cynhaliwyd cyfarfodydd ychwanegol i adolygu’r materion canlynol:

Canfyddiadau Allweddol, Barn yr Arolygydd a Rhesymau am y Farn a Gynigiwyd

Roedd archwiliad LC32 o ardaloedd storio gwastraff ymbelydrol cyfredol wedi cadarnhau bod y croniad o wastraff ymbelydrol yn cael ei reoli’n dda a’i effaith wedi gostwng lle bynnag yr oedd hynny yn ymarferol. Roedd labelu’r deunydd o safon dda ac ond ambell arsylwad mân a wnaed oedd yn berthnasol i sicrhau bod defnydd cyson o safonau parthed y rhan fwyaf o wastraff a grynhowyd. Yn gyffredinol defnyddid arfer da ym mhob maes ac mae’r tîm gwastraff yn bwrw ati i leihau croniadau potensial er mwyn sicrhau bod y risgiau oedd yn weddill yn lleddfu ALARP.

Roedd archwiliad LC33 wedi cadarnhau bod gan Magnox Cyf drefniadau a gweithdrefnau grymus er mwyn ymgymryd â chael gwared sydd yn ateb dibenion deddfwriaeth amgylcheddol. Maent wedi mynd i’r afael ag ymatebion i arsylwadau ynghylch gwella trefniadau i alinio gyda gofynion ONR i ymateb i gyfarwyddiadau ffurfiol ac mae’r cydymffurfiad yn bodloni disgwyliadau rheoleiddiol.

Er mwyn ategu archwiliad LC34 roedd Magnox Cyf wedi darparu crynodeb o ddigwyddiadau a fu yn ystod y flwyddyn flaenorol oedd yn cynnwys gollwng potensial a deunydd ymbelydrol yn dianc. Roedd archwiliad o ymateb y daliwr trwydded o’r digwyddiadau hyn yn cadarnhau bod ond ychydig o enghreifftiau o ollwng a dianc a bod y rhai hynny yn rhai mân o arwyddocâd isel yn radiolegol. Mae’r ymatebion i’r digwyddiadau wedi bod yn gymesur ac wedi eu targedu yn addas gan y daliwr trwydded. Mae’r  Archwiliad o’r Cyfarpar AETP yn cadarnhau bod gofal/rheolaeth asedau yn cael ei gyflwyno i safon dda..

Roedd cyfarfodydd ychwanegol wedi cadarnhau bod Magnox Cyf yn parhau i ganolbwyntio ar archiadau a cheisio sicrhau eu bod yn dal i fodloni gofynion cyfreithiol.

Casgliadau’r Ymyriad

O’r wybodaeth a’r dystiolaeth a gasglwyd yn ystod yr ymyriad hwn, yn fy marn i nid oedd unrhyw faterion wedi dod i’r amlwg a ystyrid fel rhai i effeithio yn anffafriol ar ddiogelwch niwclear.