research challenges for lto –cooperation between epri · pdf filefourth nuclear power...

© 2017 Electric Power Research Institute, Inc. All rights reserved.

Sherry Bernhoft

EPRI Senior Program Manager

23 to 27 October 2017

Fourth Nuclear Power Plant Life Management

Lyon, France

Research Challenges for

LTO – Cooperation

Between EPRI and IAEA on

the IGALL Programme

2© 2017 Electric Power Research Institute, Inc. All rights reserved.

Long Term Operations - Goals and Objectives

Technical basis for decision to

operate through extended life time

• Supports business case for life

extension and refurbishments

Technology to manage plant assets

throughout the lifetime

• Ageing management, asset management, and risk

management

• Address safety, performance and costs


Suppliers,

Vendors

Nuclear

Utilities

Basic Research

and

Development

Collaborative

Technology

Development,

Integration, and

ApplicationSolutions

Inputs

EPRINational Laboratories,

Universities

Our Approach


Technical Basis for LTO is Ageing Management:

Assessment

• What to inspect and when

• Inspection options

• How to dispose any observed

degradation

Inspection

• How to inspect

• What equipment and techniques are available

• What are the associated uncertainties

• What techniques need to be improved

Technical Support

• Review of inspection results

• Guidelines review and maintenance

Mitigation and Testing

• Prevent or reduced degradation

• Irradiated material testing

• Non-irradiated material testing

The technical basis for ageing management is established, and incorporated in the

ageing management programmes

Over 125 EPRI technical reports are referenced in the IGALL

Safety Report No. 82 “IGALL”

• Guidance on recommended ageing management programmes and typical TLAAs

• Published in 2015

• IGALL database on IAEA web site contains:

• 84 Ageing Management Programmes (AMPs)

• 28 Time Limited Ageing Analysis (TLAAs)

• Technological obsolescence programme

• More than 2000 consolidated line items in AMR tables (totally more 7000 line items

collected from MS)

5

Objectives and activities in 2016-2017 (Phase 3):

1.Prepare IGALL Safety Report, version 2018

2.Update IGALL database and enhance its completeness

3.Support MS in implementing and using IGALL

IGALL Phase 3 Organization

WG1 - Mech.

Components

Up to 40 members

Steering Committee1 representative per MS

WG leaders

WG2 – EI&C

components

Up to 35 members

WG3 - Civil

structures

Up to 30 members

IGALL Safety

Report

Edition 2018

IAEA QA

Procedure

6

Sherry Bernhoft,

Robin Dyle, TG Lian

Andrew Mantey Maria GuimaraesEPRI:

Phase 3 working groups updated and expanded

the Technical References and Operating

Experience, and included new information from

the NRC GALL for Second License Renewal


Internation Coordination and Collaboration is Required

On track to provide deliverables in the

2014 through 2019 timeframe

Operating

Experience

Inspection

Results

Research


Key Technical Areas for Research Needs

� Reactor pressure vessel neutron embrittlement

at high fluence

� Irradiated-assisted stress corrosion cracking of

reactor vessel internals

� Concrete degradation

� Electrical cable qualification and condition

assessment


Materials Degradation Matrix

� Every primary component

� Every primary material

� Every degradation mechanism

� Every gap in our understanding

Global relevance: Includes PWR, BWR, VVER and CANDU materials


Reactor Vessels and Core Internals

� Ageing: Neutron fluence and operating environment

– Embrittlement of reactor vessel materials

– Irradiation assisted stress corrosion cracking (IASCC) and void swelling of core internals

� BWR Vessel Internals Program and PWR Materials Reliability Program

– Living programmes to monitoring and managing ageing of primary system metals

� Extend existing IASCC models on initiation and crack growth rate for VVER internals materials

� Harvested materials provide confirmation of aging models

Baffle

Baffle Plate

Edge Bolt

Baffle to

Former Bolt

(Long & Short)

Corner Edge

Bracket Baffle to

Former Bolt

Core Barrel to

Former Bolt

Core Barrel

Former


Jose Cabrera “Zorita” Project

� Unique opportunity to extract highly

irradiated reactor internals material

� Understand fluence effects– Mechanical properties: tensile strength, fracture

toughness, crack initiation and growth

– Microscopic properties: grain boundary

chemistry and size, void formation, and hydrogen

and helium production

� Support ongoing operation of current fleet

Collaboration between global utilities and regulators; managed by EPRI

Jose Cabrera NPP “Zorita”

Westinghouse design

1968 – 2006 (~26 EFPY)


Concrete and Civil Structures

� Ageing: Possible impacts on structural integrity due to

– Alkali Silica Reaction (ASR)

– Irradiation and gamma heating

– Spent fuel pool boric acid attack

– Creep fatigue of tendon containment structures

� EPRI technical reports provide the basis for concrete

ageing management

� Research continues

– Nondestructive testing techniques

– Modeling for structural assessments

– Repair methods

Developing management and

evaluation programs for ASR

Modeled concrete structures exposed to

high levels of radiation demonstrate

remaining margins of safety

Developing techniques for

nondestructive inspections


Reactive Aggregates

Series of technical papers for ASR detection and management:

�Detection of ASR Guidance – Dec 2015

�Cracking Index Criteria for Potential ASR – Sept 2016

�Structural Deformation Due to Expansion from ASR – Dec 2016

�Monitoring Strategies – May 2017

�Structural Implications – June 2017

�Final Report for Aging Management of ASR – Dec 2017

�Training on use of ASR technical reports – Early 2018

� Need to screen for ASR susceptibility

� If detected establish a program for crack indexing and monitoring for building deformations


Irradiation Impacts and Gamma Heating

� Series of technical reports have been published:

�Effects of Radiation on Concrete Literature Survey – May 2012

�Expected Condition of Reactor Cavity Concrete After 80 Years

– March 2014

�Structural Disposition of Radiation Exposure for BWR Pedestal

– June 2016

�Structural Model for PWR Reactor Cavity Support – Dec 2016

�Long-term Impact of Radiation Heating on PWR Shield Wall

Concrete – Dec 2016

�Comprehensive Report on Irradiation Impacts on Concrete

(with incorporation of NRC comments) – Early 2018

Modeling concrete structures

exposed to high levels of radiation

demonstrated safety margins exist


Electrical Cables

� Ageing: Insulation degradation due to

radiation, temperature and humidity

� EPRI ageing management guidance

for low and medium voltage cables

� Research continues to support asset

management

– Condition monitoring technologies

– Remaining useful life (RUL)

diagnostics


Cross Reference of EPRI Reports

� IGALL AMPS for both active and passive components:

– Report ID # 3002008058 ‘EPRI Product Mapping to the

IGALL’

� Based on the US NRC GALL report and the Equipment

Reliability Index for implementation of INPO AP-913


Future Work

� Support for Lead plants in the US for Second License

Renewal – 60 to 80 years of operation

� IGALL Phase 4, 2018 – 2019

– Guidance for regulators to review preparedness for safe LTO

(similar to the Standard Review Plans of the US NRC)

– Technical reports (and AMPs) on aging management for

delayed construction, extended outages

– Incorporation of lessons learned from US Second License

Renewal AMPs

– New generic operating experinces and Interim Staff Guidance

Reports from the NRC

– New research findings

– New best practices for AMP implementation

Operating

Experience

Inspection

Results

Research

Living Programmes

Technical reports are

updated based upon:


TogetherIShaping the Future of Electricity

research challenges for lto –cooperation between epri · pdf filefourth nuclear power...

Documents