Office for Nuclear Regulation

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Magnox Limited, Wylfa, Level 1 exercise observation

Executive summary

Purpose of Intervention

This inspection was one of a series of planned inspections for 2019/20, which are informed by the ONR Decommissioning Fuel and Waste (DFW) sub-division strategy.

The purpose of this inspection was to seek assurance that the licensee’s emergency arrangements and its emergency response personnel have the capability to deal effectively with emergencies on the site and their consequences. 

Interventions Carried Out by ONR

The site’s compliance with Licence Condition 11 (Emergency Arrangements) was inspected by ONR inspectors observing a demonstration emergency exercise held on 17 September 2019.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

Wylfa has been de-fuelling its reactors for several years and sending the used fuel to Sellafield.  The last fuel was despatched form site on 18 September 2019, thereby removing a very large proportion of the nuclear hazard from the site.  The site is now conducting a fuel free verification process that is scheduled to be completed in October 2019.  Following this activity, Wylfa intend to confirm that the Radiation (Emergency Preparedness and Public Information) Regulations 2019 (REPPIR) requirements for off-site emergency planning and prior information to the public no longer apply.  It is against this background that ONR observed Wylfa’s implementation of its revised emergency arrangements that have been developed to manage on-site emergencies, and which are consistent with other defueled Magnox reactor sites.

Prior to the exercise, ONR examined the exercise scenario, judging that it represented sufficient challenge to the licensee’s personnel and was proportionate to the remaining magnitude and nature of the hazard on the fuel free site.

ONR’s inspectors judged that the licensee provided an adequate demonstration of its emergency arrangements and, based upon their observation of the exercise, judged that the licensee’s emergency response personnel have the capability to cope effectively with emergencies with on-site consequences.

Conclusion of Intervention

I identified no matters that in my opinion could adversely affect nuclear safety.  My findings were shared with and accepted by the licensee.

Pwrpas yr Ymyriad

Roedd yr archwiliad hwn yn un o gyfres o archwiiadau a gynlluniwyd ar gyfer 2019/20, sy'n cael eu llywio gan strategaeth is-adran Dadgomisiynu Tanwydd a Gwastraff (DFW) yr ONR.

Pwrpas yr archwiliad hwn oedd ceisio sicrwydd bod gan drefniadau brys y trwyddedai a'i bersonél ymateb brys y gallu i ddelio'n effeithiol ag argyfyngau ar y safle a'u canlyniadau. 

Ymyriadau a Gynhaliwyd gan ONR

Archwiliwyd cydymffurfiad y safle ag Amod Trwydded 11 (Trefniadau Brys) gan archwilwyr yr ONR a arsylwodd arddangosiad o ymarfer brys a gynhaliwyd ar 17 Medi 2019.

Esboniad o'r Farn os na Farnir bod y System Ddiogelwch yn Ddigonol

Ddim yn gymwys.

Canfyddiadau Allweddol, Barn yr Archwiliwr a Rhesymau dros Ddyfarniadau a Wnaed

Mae Wylfa wedi bod yn dad-lenwi ei adweithyddion ers sawl blwyddyn ac yn anfon y tanwydd sydd wedi’i ddefnyddio i Sellafield. Anfonwyd y tanwydd olaf o'r safle ar 18 Medi 2019, a thrwy hynny’n cael gwared ar gyfran fawr iawn o'r perygl niwclear o'r safle. Mae'r safle bellach yn cynnal proses o wirio bod y safle’n rhydd rhag tanwydd y bwriedir ei chwblhau ym mis Hydref 2019. Yn dilyn y gweithgaredd hwn, mae Wylfa yn bwriadu cadarnhau nad yw gofynion Rheoliadau Ymbelydredd (Parodrwydd Brys a Gwybodaeth Gyhoeddus) 2019 (REPPIR) ar gyfer cynllunio brys oddi ar y safle. ac nid yw gwybodaeth flaenorol i'r cyhoedd yn berthnasol bellach. Yn erbyn y cefndir hwn yr arsylwodd ONR y modd yr oedd Wylfa yn gweithredu ei drefniadau brys diwygiedig a ddatblygwyd i reoli argyfyngau ar y safle, ac sy'n gyson â safleoedd adweithyddion Magnox eraill sydd wedi'u dad-lenwi.

Cyn yr ymarfer, archwiliodd ONR senario yr ymarfer, gan farnu ei fod yn her ddigonol i bersonél y trwyddedai a'i fod yn gymesur â maint a natur y perygl sy’n weddill ar y safle sy’n rhydd rhag tanwydd.

Barnodd archwilwyr ONR fod y trwyddedai wedi darparu arddangosiad digonol o’i drefniadau brys ac, yn seiliedig ar eu harsylwad ar yr ymarfer, barnwyd bod gan bersonél ymateb brys y trwyddedai’r gallu i ymdopi’n effeithiol ag argyfyngau gyda chanlyniadau ar y safle.

Canlyniad yr Ymyriad

Ni nodais unrhyw faterion a allai, yn fy marn i, effeithio'n andwyol ar ddiogelwch niwclear. Rhannwyd fy nghanfyddiadau gyda'r trwyddedai ac fe'u derbyniwyd ganddo.