update on the status of the crp on modular htgr safety design

Update on the status of the CRP on

Modular HTGR Safety Design

Frederik ReitsmaGas-Cooled Reactors Technology

Nuclear Power Technology Development Section

Division of Nuclear Power | Department of Nuclear Energy

10th GIF-IAEA Interface Meeting

IAEA Headquarters, Vienna. 11-12 April 2016

111-12 April 2016 10th GIF-IAEA Interface Meeting

International Atomic Energy Agency

Overview

• Background

• Description of CRP

• Status, progress and plans

• Outlook

11-12 April 201610th GIF-IAEA Interface Meeting 2


Background (1/3)

� Fukushima Daiichi - March 2011

� Safety of nuclear installations once again under

scrutiny

� Developers of technologies have an added

responsibility to demonstrate that whatever

nuclear reactor design they propose will be able

to cope with challenges of the type that were

encountered at the Fukushima Daiichi nuclear

power plant



Background (2/3)

� Modular HTGRs

� The intrinsic properties of modular high temperature

gas cooled reactors (HTGRs) minimize and, in many

cases, eliminate concerns over off-site and on-site

power

� Typically no need for active safety systems or

operator actions to avoid large radionuclide releases

� Need to consider multi-reactor plant sites

� BUT, the reactor designer must still assure a safe

design.



Background (3/3)

� Safety Design of Modular HTGRs

� The development and implementation of

comprehensive safety design criteria that take

HTGR-specific characteristics into account would

provide a high level of assurance that modular

HTGRs are consistently designed, constructed, and

operated in a manner that takes advantage of these

intrinsic properties, while also avoiding unintended

compromises in plant safety.



CRP – HTGR Safety

• Was proposed by Japan as a Member State (at the TWG-

GCR 2013 meeting).

• 9 to investigate and make proposals on safety design

criteria for the HTGR, referring to the LWR safety standard

and worldwide safety design standards for current HTGRs.

• two reference designs (prismatic and pebble-bed), with the

understanding that safety design criteria should be

technology-neutral.

• CRP should show the safety advantage of the HTGR to

nuclear experts in the other fields.

• Should make a contribution towards efforts to harmonize the

design safety standards (to make them technology-neutral)

611-12 April 201610th GIF-IAEA Interface Meeting


CRP – HTGR Safety

• It is hoped that the technical information gathered during the

CRP will be useful for possible future activities to develop

IAEA Safety Standards for HTGRs

• This falls outside the NE scope and is in the Department

of Nuclear Safety and Security area of responsibility

• Two publications planned (2017/18):

• NE Series Report: Modular High Temperature Gas-cooled

Reactor Safety Design Criteria

• TECDOC: Modular High Temperature Gas-cooled Reactor

Safety Design Methodology and Implementation Examples


International Atomic Energy Agency8

Modular High Temperature Gas-cooled Reactor Safety Design

� A unique safety design and safety criteria approach is needed for modular HTGR due to its

inherent safety characteristics, no core-melt possibility and limited safety system

requirements

� investigate and make

proposals on design

criteria

� take lessons learned

from Fukushima Daiichi

accident into account

� clarifying the safety

approach and safety

evaluation criteria

� design and design

extension conditions

� multiple reactor modules

and co-generation

considerations



The specific outcomes as defined

1) Definition of Modular HTGRs.

2) Discussion of the inherent or intrinsic characteristics of the fuel and

moderator materials and coolant.

3) Discussion of the natural / passive features such as heat removal and

control of heat generation.

4) Two reference designs used in the safety evaluation, one pebble bed

and one prismatic design with initial emphasis on the LEU fuel of a

steam cycle plant progressing to alternative fuel and to process heat

configurations utilizing a gas turbine or an intermediate heat

exchanger.

5) Possibly refined HTR fuel manufacturing specifications and Quality

Control / Quality Assurance (QC/QA) methods and techniques (taking

the latest experience into account).




6) Summary of the process flow from top level requirements to Safety

Design Approach to licensing basis events to required safety functions

to the safety design criteria.

7) Summary of relevant past work related to HTGR safety.

8) Description of the Modular HTGR Safety Design Approach including its

approach to defence in depth in terms of the radionuclide retention

allocation to the barriers.

9) Discussion of the spectrum of representative licensing basis events

and the SSCs relied on to meet the offsite dose requirements.

10) A clear delineation of the treatment of design basis events versus

beyond design basis events in terms of the evaluation and the

acceptance criteria, if such delineation can be elaborated and

comprehensibly transferred to the public




11) Discussion of how the process and its implementation to the selected

designs accounts for the Fukushima lessons learned (e.g., events

impacting more than one reactor, spent fuel, power supplies, active

systems, operator actions, etc.).

12) Identification of any Research and Development gaps or analysis

method Verification and Validation needs for the Modular HTGR.

13) The economic impact of the recommended safety approach and

Safety Design Criteria.

14) The latest IAEA safety design criteria will be studied and HTGR

specific interpretations or possible changes will be suggested by the

participants for possible consideration by the appropriate member

state authorities and NS department.



USA proposed bottom-up approach


International Atomic Energy Agency10th GIF-IAEA Interface Meeting 13

Status, Outlook

• Implementation started December 2014

• Good support for the CRP

– 10 participating organizations from 9 member states: China, Germany , Indonesia, Kazakhstan, Korea (Republic of), Japan , UK, Ukraine, USA

– Possible interest: Russian Federation

• Scheduled RCMs

– 1st RCM took place 9-12 June 2015

– 2nd RCM scheduled for 13-17 June 2016 (Vienna)

• The research, design approach and discussion of “HTGR Safety Design Criteria” has been identified as a possible topic of common interest between IAEA and GIF

11-12 April 2016


Thank you!

Frederik Reitsma

Gas-Cooled Reactors Technology

Nuclear Power Technology

Development Section

Email: [email protected]


update on the status of the crp on modular htgr safety design

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