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The Application of Resilience Learning toUK Spent Fuel Management Facilities

Phil Hallington

IAEA Vienna, 19-22 March 2012

IAEA-CN-209-025

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Scope

Overview of Sellafield

Nuclear Safety Principles

Resilience Evaluation Process [RESEP]

Peer Review

Building the Programme

Sellafield Considerations

Conclusions

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Sellafield Context

7 shutdown reactors

2 Reprocessing plants

Waste Management High hazard legacy facilities

Product Storage

Supporting Infrastructure

Low temperature, low pressure processes

Very large inventory of radioactive material

Relatively low rates of change to loss of cooling

Aging facilities and infrastructure

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Nuclear Safety Principles

Maintaining containment

Maintaining cooling

Maintaining control of reactivity

Maintaining control of chemistry

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30-60-90 Day Plan

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Resilience Architecture

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Goals for RESEP

Provides a structured approach for the whole site

Allows for progression of events from single plant to

whole site Searches for cliff-edge effects

Develops timelines for critical safety functions (CSF)

Addresses infrastructure requirements on and off-site Identifies opportunities for resilience enhancement

Provides a key focus for damage control teams

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Dynamics of Mitigation

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Timeline - Conceptual

Initiating

Ev

ent

Time

Current Backups

Alternative Backups

Mitigating Actions

Current Backups

Alternative BackupsCurrent Backups

Event A

Event B

Event C

72 Hrs 1 week

SevereAccident

Analysis

SevereAccidentManagement

Strategies

Safety CaseBoundary

RealCliff Edge

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RESEP Process Diagram

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RESEP Workshops

The key characteristics of a successful workshop are:

Strong representation from plant operators who know the plant

and are likely to be confronted with securely challengingsituations

Support from a knowledgeable technical team who haveprepared thoroughly

An open and questioning environment which is respectful of allcontributions

Methodical capture of all key observations.

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Building the Programme

PHASE 1 SITE RESILIENCE

PHASE 2 SITE RESILIENCEDEFINED SCOPE

EMERGINGSCOPERespond to

ONR InterimReport

Develop andImplement

RESEP

Process

Respond to

WANO SOER2011-2

CompleteENSREG

Stress Tests

and report

Develop WiderResilience

Architecture

Accelerateddelivery of

SAA/SAMS

ImplementRESEP

Improvements

Respond toWANO SOER

2011-3

Respond toFurther LFEfrom Japan

Respond toadditional

ONR Report(s)

ALARPconsiderationof outputs

Initiate Studiesinto identifiedproblems

Key topics for

peer review

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Summary of Key Programme Outcomes

A resilience architecture which will provide an appropriate level of robustness interms of responses, maintainability and capability to successfully managesignificant challenges to the business

Maximum learning is taken from events in Japan and effectively applied across

our operations (including effective communication with industry colleagues) Consequence led and risk informed analysis defining appropriate mitigating

actions and countermeasures which will arrest the progression of faultsequences

Investment in equipment and resources is justified against the severity ofconsequences that are effectively mitigated

A realistic view is taken of common cause effects and potential dominosituations that may arise

Effective engagement of plants and supporting functions is essential to thesuccess of these activities,

Wider public confidence in the Nuclear Industry and matters of safety is secured

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Decision Making Process

Decision making process for considerations Auditable, proven and accepted by key stakeholders

Including strong element of peer review

Focuses effort where greatest benefit can be derived

Flexible to late changes in understanding

Leads to an accepted resilience improvement index

Implementation

Actions to be delivered locally, by plants

Progress to be monitored centrally, by programme

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Draft Principles

Draft Principles for Site Resilience Following an incident, as far as possible, facilities should

be self-reliant for a suitable period (typically 24 hours).

They should also have the local capability to get the plantinto control and then into a quiescent state, withoutexternal support.

Similarly, Site should be self-reliant for a longer period,without external support, typically at least 7 days

Favouring simple, robust solutions providing value.

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Conclusions

Faced with translating reactor-based stress tests onto a complex suite ofnuclear chemical reprocessing plants, Sellafield Limited and its specialistsuppliers have developed an effective and systematic method of assessingresilience.

This method (RESEP) has focussed on the plants within the greatest potentialconsequences and has provided successful new insights into many facilities

beyond their Design Basis. The process has identified a range of considerations and actions which willmake a genuine and sustainable improvement in resilience.

To be success RESEP needs Thorough preparation

Knowledgeable inputs An open environment where questioning is welcomed

Close engagement with Regulators and industry colleagues has been importantto success

We at Sellafield are committed to sustaining this approach to enhanceresilience and wide incorporate this approach into our long-term periodic review

of safety cases (LTPR) which is a cornerstone of the licensing system.