Step 1 GDA statement
01 August 2024
In October 2023, the Office for Nuclear Regulation (ONR), together with the Environment Agency and Natural Resources Wales, began Step 1 of the Generic Design Assessment (GDA) for the Holtec SMR-300 design. During the last 10 months, we have undertaken activities to initiate and establish the project and to prepare for technical assessment in later steps. These activities are defined within our GDA guidance document, Guidance to Requesting Parties (ref. [1]).
Holtec International is the Requesting Party (RP) for the GDA, represented in the UK by its wholly owned subsidiary Holtec Britain. The GDA is being conducted on a twin unit design, comprising two SMR-300 reactors and associated plant. Innovation comes from the extensive use of passive safety systems and a single steam generator per reactor. The design is at an advanced concept stage of development and is being further developed during the GDA in parallel with the RP’s safety, security, safeguards (and environmental) cases. A recent change prior to entering GDA increased reactor power output from 160 Megawatts electrical (MWe) to 300 MWe and introduced two reactor coolant pumps for use during normal operation.
During Step 1 we have undertaken more than 100 engagements and assessed more than 20 submissions. The information submitted (ref. [2]), including a gap analysis against regulatory expectations, met all the requirements from our guidance and demonstrated a good understanding of UK practice and regulatory expectations. We take confidence from these submissions that the RP has a clear view of what is needed to progress through the GDA and how it will justify its design.
Holtec International has confirmed that it only intends to complete GDA up to the end of Step 2, which is an assessment of the fundamental adequacy of the design and safety and security cases.
Given the two-step approach to this GDA a Design Acceptance Confirmation (DAC) will not be provided. The output from this two-step GDA will be a Step 2 GDA statement that will reflect the agreed GDA scope and ONR’s assessment to that point in time. It will provide an indication of confidence, based upon the assessment conducted to that point, on ONR’s judgement on the fundamental acceptability of the design and whether it is potentially capable of being built and operated on a site bounded by the generic site envelope, in a way that is acceptably safe and secure.
The overall duration for Step 2 of GDA is expected to be 14 months, completing in October 2025.
We have agreed a defined GDA scope with the RP (ref. [3]). This is consistent with previous GDAs, taking into account the RP’s intention to only complete Steps 1 and 2 of GDA. Where aspects are declared as being of reduced or out of scope, we are content that these are justified and appropriate. Overall, we are satisfied that the agreed GDA scope will allow us to undertake a meaningful assessment of the generic design.
Holtec Britain is developing the Safety, Security, Safeguards and Environmental Case (SSEC) for the generic SMR-300 design. The SSEC submitted during GDA will comprise a Preliminary Safety Report, Generic Security Report, Preliminary Safeguards Report and Preliminary Environment Report. It will provide the primary basis for any regulatory judgements made in Step 2. The SSEC scope covers all technical topics as defined in our Guidance to Requesting Parties (ref. [1]). We are satisfied that the proposed SSEC approach is logical and suitably structured.
We have agreed a submission schedule with the RP, which includes the submission of more than 140 SSEC documents during Step 2 (ref. [4]). We are content that this aligns with our assessment plans, the agreed GDA scope and the RP's declared schedule for GDA. The RP has stated it has sufficient resource to deliver the submissions identified for Step 2 to the agreed schedule.
In line with our guidance, the RP undertook a self-assessment and review of its own readiness to proceed to Step 2. We judge that the process undertaken by the RP was reasonable, proportionate and sufficiently robust for this step of GDA. The overall conclusion of the RP's readiness review is that it considers itself ready to begin Step 2.
We undertook a review of our own readiness to proceed to Step 2 and conclude that, based on the agreed GDA scope and submission schedule, we can undertake a meaningful assessment during Step 2 which warrants the continued deployment of regulatory resource. Our readiness review demonstrated that we consider both ourselves and the RP ready to proceed to Step 2 of GDA for the Holtec SMR-300.
Full details for the basis of this statement are summarised in our Step 1 summary report (ref. [5]).
In summary:
· the RP has completed all the requirements for Step 1 from our guidance
· interactions with the RP throughout Step 1 have been professional and constructive, and we have confidence that this will continue
· the RP has made good progress in developing its organisation and arrangements to support GDA
· the agreements necessary to undertake the GDA are in place, or have developed sufficiently for this point in the project with clear plans for further development
· the RP has demonstrated a good understanding of our regulatory expectations and has confidence that these can be met by its design and safety, security and safeguards case
· we have improved our understanding of the generic SMR-300 design and safety, security and safeguards case and have used this to inform our planning for further assessment activities
· we, and the RP, are ready to proceed to Step 2 of the GDA
· we therefore conclude that the Holtec SMR-300 design can proceed to Step 2 of the GDA
References
1. ONR, New Nuclear Power Plants: Generic Design Assessment Guidance to Requesting Parties, ONR-GDA-GD-006, Revision 0, October 2019
2. Holtec Britain Limited, SMR-300 GDA Master Document Submission List for GDA, HI-2240061, Issue 3, July 2024. (Record ref. ONRW-2019369590-10725).
3. Holtec Britain Limited, SMR-300 UK Generic Design Assessment Scope, HI-2240121, Issue 1, May 2024. (Record ref. ONRW-2019369590-9727).
4. Holtec Britain Limited, GDA Step 1 and 2 Submission Schedule, HI-2240122-R3.1, June 2024. (Record ref. ONRW-2019369590-10105).
5. ONR, Project Assessment Report - Generic Design Assessment of the Holtec SMR-300 – Step 1 Summary, ONRW-2019369590-11052, Rev. 1, August 2024
Datganiad GDA Cam 1 Holtec
Ym mis Hydref 2023, aeth y Swyddfa Reoleiddio Niwclear (ONR), ynghyd ag Asiantaeth yr Amgylchedd a Chyfoeth Naturiol Cymru, ati i ddechrau Cam 1 yr Asesiad Cynllun Generig (GDA) ar gyfer y cynllun Holtec SMR-300. Yn ystod y 10 mis diwethaf, rydym wedi gwneud gweithgareddau i gychwyn a sefydlu'r prosiect ac i baratoi ar gyfer asesiad technegol mewn camau diweddarach. Mae'r gweithgareddau hyn wedi eu diffinio yn ein dogfen arweiniad GDA, Arweiniad i Bartïon sy'n Gwneud Cais (cyf. [1]).
Holtec International yw'r Parti sy'n Gwneud Cais (RP) am y GDA, ac mae wedi ei gynrychioli yn y DU gan ei is-gwmni y mae'n eiddo arno'n gyflawn, Holtec Britain. Mae'r GDA yn cael ei weithredu ar gynllun uned ddeuol, sy'n cynnwys dau adweithydd SMR-300 a chyfarpar cysylltiedig. Daw arloesiad o'r defnydd estynedig o systemau diogelwch goddefol ac un generadur stêm fesul adweithydd. Mae'r cynllun ar gam cysyniad lefel uwch o ddatblygiad ac mae'n cael ei ddatblygu ymhellach yn ystod y GDA yn unol ag achosion diogelwch, diogeledd ac amddiffyn (ac amgylcheddol) yr RP. Roedd newid diweddar cyn mynd i mewn i'r GDA wedi cynyddu allbwn pŵer yr adweithydd o 160 Megawatt trydanol (MWe) i 300 MWe ac wedi cyflwyno dau bwmp oerydd adweithydd i'w defnyddio yn ystod gweithrediad arferol.
Yn ystod Cam 1 rydym wedi gwneud mwy na 100 o ymgysyllitadau ac wedi asesu mwy nag 20 cyflwyniad. Roedd yr wybodaeth a gyflwynwyd (cyf. [2]), yn cynnwys dadansoddiad bwlch yn erbyn disgwyliadau rheoleiddiol, wedi ateb yr holl ofynion o'n harweiniad ac wedi dangos dealltwriaeth dda o arferion a disgwyliau rheoleiddiol y DU. Rydym yn teimlo'n hyderus o'r cyflwyniadau hyn bod gan yr RP ddarlun clir o'r hyn sydd ei angen i symud ymlaen drwy'r GDA a sut y bydd yn cyfiawnhau ei gynllun.
Mae Holtec International wedi cadarnhau ei fod yn bwriadu cwblhau GDA hyd at ddiwedd Cam 2 yn unig, sy'n asesiad o ddigonolrwydd syfaenol y cynllun a'r achosion diogelwch a diogeledd.
O ystyried yr agwedd dau gam tuag at y GDA hwn, ni fydd Cadarnhad o Dderbyniad Cynllun (DAC) yn cael ei ddarparu. Yr allbwn o'r GDA dau gam hwn fydd datganiad GDA Cam 2 a fydd yn adlewyrchu'r cwmpas GDA y cytunwyd arno ac asesiad ONR hyd y pwynt hwnnw mewn amser. Bydd yn rhoi arwydd o hyder, ar sail yr asesiad a wnaed hyd y pwynt hwnnw, ar feirniadaeth ONR am dderbynioldeb sylfaenol y cynllun ac a fyddai o bosib yn gallu cael ei adeiladu a'i weithredu ar safle sydd â'r amlen safle generig yn ffin iddo, mewn ffordd sy'n dderbyniol o ddiogel.
Disgwylir i hyd cyffredinol Cam 2 y GDA fod yn 14 mis, gan gwblhau ym mis Hydref 2025.
Rydym wedi cytuno ar gwmpas GDA diffinedig gyda'r RP (cyf. [3]). Mae hyn yn gyson gydag asesiadau GDA blaenorol, gan ystyried bwriad yr RP i gwblhau Camau 1 a 2 yn unig o'r GDA. Lle cyhoeddir bod agweddau wedi eu gostwng neu y tu allan i'r cwmpas, rydym yn fodlon bod y rhain wedi eu cyfiawnhau ac yn briodol. Yn gyffredinol, rydym yn fodlon y bydd cwmpas y GDA yn caniatáu i ni wneud asesiad ystyrlon o'r cynllun generig.
Mae Holtec Britain yn datblygu'r Achos Diogelwch, Diogeledd, Amddiffyniad ac Amgylcheddol (SSEC) ar gyfer y cynllun SMR-300 generig. Bydd yr SSEC a gyflwynir yn ystod GDA yn cynnwys Adroddiad Diogelwch Rhagarweiniol, Adroddiad Diogeledd Generig, Adroddiad Amddiffyniadau Rhagarweiniol ac Adroddiad Amgylchedd Rhagarweiniol. Bydd yn darparu'r sail sylfaenol ar gyfer unrhyw feirniadaethau rheoleiddiol a wneir yng Ngham 2. Mae'r cwmpas SSEC yn ymdrin â'r holl bynciau technegol fel y maent wedi eu diffinio yn ein Harweiniad i Bartïon sy'n Gwneud Cais (cyf. [1]). Rydym yn fodlon bod yr agwedd SSEC arfaethedig yn rhesymegol ac wedi ei strwythuro'n addas.
Rydym wedi cytuno ar amserlen gyflwyno gyda'r RP, sy'n cynnwys cyflwyno mwy na 140 o ddogfennau SSEC yn ystod Cam 2 (cyf. [4]). Rydym yn fodlon bod hyn yn alinio gyda'n cynlluniau asesu, y cwmpas GDA y cytunwyd arno ac amserlen gyhoeddedig RP ar gyfer GDA. Mae'r RP wedi datgan bod ganddo ddigon o adnoddau i ddarparu'r cyflwyniadau a nodwyd ar gyfer Cam 2 i'r amserlen y cytunwyd arni.
Yn unol â'n harweiniad, gwnaeth yr RP hunan-asesiad ac adolygiad o'i barodrwydd ei hun i symud ymlaen i Gam 2. Rydym yn barnu bod y broses a weithredwyd gan yr RP yn rhesymol, cymesur a digon cadarn ar gyfer y cam hwn o'r GDA. Casgliad cyffredinol adolygiad parodrwydd yr RP yw ei fod yn ei ystyried ei hun yn barod i ddechrau Cam 2.
Gwnaethom adolygiad o'n parodrwydd ein hunain i symud ymlaen i Gam 2 a daethom i'r casgliad, ar sail yr amserlen gyflwyno a'r cwmpas GDA y cytunwyd arnynt, y gallwn wneud asesiad ystyrlon yn ystod Cam 2 sy'n gwarantu defnydd parhaus yr adnodd rheoliadol. Dangosodd ein hadolygiad parodrwydd ein bod yn ein hystyried ni'n hunain a'r RP yn barod i symud ymlaen i Gam 2 y GDA ar gyfer yr Holtec SMR-300.
Mae'r manylion llawn ar gyfer sail y datganiad hwn wedi eu crynhoi yn ein hadroddiad crynodeb Cam 1 (cyf. [5]).
I grynhoi:
· mae'r RP wedi cwblhau yr holl ofynion ar gyfer Cam 1 o'n harweiniad
· mae rhyngweithiadau gyda'r RP drwy gydol Cam 1 wedi bod yn broffesiynol ac adeiladol, ac rydym yn hyderus y bydd hyn yn parhau
· mae'r RP wedi gwneud cynnydd da o ran datblygu ei sefydliad a'i drefniadau i gefnogi GDA
· mae'r cytundebau angenrheidiol i wneud y GDA yn eu lle, neu maen nhw wedi datblygu'n ddigonol ar gyfer y pwynt hwn yn y prosiect gyda chynlluniau clir ar gyfer datblygiad pellach
· mae'r RP wedi dangos dealltwriaeth dda o'n disgwyliadau rheoleiddiol ac mae'n hyderus y gellir cyflanwi'r rhain gan ei achos diogelwch, diogeledd ac amddiffyniad a'i gynllun
· rydym wedi gwella ein dealltwriaeth o'r cynllun SMR-300 generig a'r achos diogelwch, diogeledd ac amddiffyniad ac rydym wedi defnyddio hyn i hysbysu ein cynllunio ar gyfer gweithgareddau asesiad pellach
· rydym ni, a'r RP, yn barod i symud ymaen i Gam 2 y GDA
· felly, rydym yn dod i'r casgliad y gall cynllun yr Holtec SMR-300 symud ymaen i Gam 2 y GDA
Cyfeiriadau
1. ONR, New Nuclear Power Plants: Generic Design Assessment Guidance to Requesting Parties, ONR-GDA-GD-006, Adolygiad 0, Hydref 2019
2. Holtec Britain Limited, SMR-300 GDA Master Document Submission List for GDA, HI-2240061, Rhifyn 3, Gorffennaf 2024. (Cyf. cofnod ONRW-2019369590-10725).
3. Holtec Britain Limited, SMR-300 UK Generic Design Assessment Scope, HI-2240121, Rhifyn 1, Mai 2024. (Cyf. cofnod ONRW-2019369590-9727).
4. Holtec Britain Limited, GDA Step 1 and 2 Submission Schedule, HI-2240122-R3.1, Mehefin 2024. (Cyf. cofnod ONRW-2019369590-10105).
5. ONR, Project Assessment Report - Generic Design Assessment of the Holtec SMR-300 – Step 1 Summary, ONRW-2019369590-11052, Adolygiad 1, Awst 2024