AHTR Project Status (PBMR Restart)

INPRO Technical Review Meeting

November 2016

Mmeli Fipaza

Programme Engineer and Director

Outline

• About “Eskom”

• Potential for PBMR

• Options for future development

• Key Lessons Learned

• Priorities and Scope

• Next steps

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About Eskom

• Strategic 100% state-owned electricity utility, strongly supported by the government

• Supplies approximately 95% of South Africa’s electricity

• Performed 158 016 household electrification connections during the year

• As at 31 March 2016:

– 5.6 million customers (2015: 5.3 million)

– Net maximum generating capacity of 43GW

– 17.4GW of new generation capacity being built, of which 6.2GW already commissioned

– Approximately 377 2871 km of cables and power lines

– 47 987 employees in the group

Nuclear

Gas

Coal

Hydro

Pumped Storage

Generation capacity – 31 March 2016

85.1%

5.7%

4.4%

3.4% 1.4%

43GW

of nominal

capacity

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Note:

* Solar PV Plants at Lethabo (0.575MW) & Kendal (0.620MW) are in operation phase

• ~ 17 082MW of new capacity (5 756MW installed and

commissioned) • ~ 4 700km of required transmission network

(3 899.3km installed) • 20 600MVA planned (20 195MVA installed)

New generation capacity and transmission networks 2005–2018

Commissions of new stations

Un

der

Co

nstr

ucti

on

/

co

mp

lete

In

dev

elo

pm

en

t

• None • Nuclear–site development and front end planning

• Biomass • Primary Energy

projects (Road & Rail)

• Sere wind (100MW) • Pilot Concentrated Solar

Power (100MW) • Photovoltaic (Own use*)

• Refurbishment and air quality projects

• 60 Grid strengthening projects

• Komati (1 000MW) • Camden (1 520MW) • Grootvlei (1 180MW)

• 3 700MW

• Medupi (4 764MW) • Kusile (4 800MW)

• 9 564MW

• Ankerlig (1 338.3MW) • Gourikwa (746MW) • Ingula (1 332MW) • Solar PV installations

at MWP (0.4MW)

• 3 518MW (1)

• Arnot capacity increase (300MW)

• Matla refurbishment • Kriel refurbishment • Duvha refurbishment

• 300MW

• 765kV projects • Central projects • Northern projects • Cape projects

• ~ 4 700km

Mpumalanga

refurbishment Return-to-service (RTS) Base load Peaking & renewables Transmission

First unit Last unit

Medupi

Kusile

Ingula

2013

2014

2014

2017

2014

2018

(1) Includes 1.62 MW for Solar PV (MWP, Lethabo & Kendal) Source: Eskom Group Capital Division (Construction Management)

Medupi is the first coal-generating plant in Africa to use supercritical power generation technology

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Koeberg Plant Information

• Two 900MWe three loop PWRs

• Built by French consortium.

• Unit 1 commissioned in 1984

• Unit 2 commissioned in 1985

• Operates on 15-18 month cycles

• Two licenced fuel suppliers

• High density fuel racks installed in late 1990’s

• During re-racking some fuel assemblies were placed in casks, and plan is to utilize casks in future until the national used fuel policy and national storage facility is finalized.

• Large area proclaimed as Nature reserve with free access to public

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PLANT SAFETY (PSA)

• The baseline Core Damage Frequency for Koeberg is below the International Atomic Energy Agency level for new nuclear power stations.

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Result of first Safety

Re-assessment

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Potential for PBMR

• PBMR was based on demonstrated German High Temperature Gas Cooled Reactor (PBMR) technology.

• The business case developed by McKinsey & Co in 2002, based on the 400MWth design developed by PBMR (Pty) Ltd, showed a large international market, being competitive with fossil fuelled plant at the then hydrocarbon prices (~$20/ton coal and ~$3/GJ natural gas).

• The nuclear safety level for the PBMR was significantly higher than is claimed for any current nuclear power plant (in service or under construction) such that engineered safety systems and off site emergency planning were not required.

• The construction schedule for the PBMR was in the order of 24 months from pouring concrete to synchronization (Sargent & Lundy).

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Why the PBMR cannot be immediately restarted

• There are four key elements that PBMR (Pty) Ltd had in place in the period up to its mothballing, these being:-

• Technology Basis

• Plant Design

• Technical staff and organization (over 500 people)

• Established supply chain of component designers and suppliers (e.g. MHI for turbines, ENSA for pressure vessels, SGL for graphite, IST for nuclear auxiliary systems, etc)

• Of these the technology basis and the plant design have been largely maintained but without the staff PBMR developed from its start in the mid 1990s and the supply chain it could not be immediately restarted.

• The supply chain elements have in some cases ceased to exist (e.g. IST) and with others it is very difficult to imagine that they would be confident enough in a new PBMR project to commit to supporting it.

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PBMR Lessons Learnt

• The PBMR project in South Africa fundamentally failed due to a number of principal factors:

• The lack of a political and financial supporting framework in Government and a lack of understanding what was required to support a new nuclear technology development and build program in South Africa

• The growth in the size of PBMR Company was too fast and the scale and complexity of the project became unsustainable

• The progress and lack of maturity of the design of the nuclear reactor and the fuel plant and the complexity of manufacturing and construction of nuclear components in a new nuclear technology environment and immature and complex nuclear licensing framework was underestimated by PBMR management

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Government Lessons Learnt (1/2)

• The project must fit into a long term planning framework or vision for the country

• There must be an objective and a clearly articulated business case that supports government’s involvement in the project

• Unequivocal support at all levels within government

• There must be a supportive policy and legislative framework

• There is a need for strong leadership from government in rolling out strategic projects

• Secure domestic markets that provide a spring board for commercial success

• Funding strategy that supports the long term objectives of the project

• Balanced and beneficial strategic partnerships that supports the long term objectives of the project

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Government Lessons Learnt (2/2)

• Projects must be preceded by a comprehensive assessment of project feasibility

• Appropriate commercialisation strategy that considers the maturity of the technology

• Independent project assurance for independent verification of project information

• Commitment to take the tough decision on the project’s future based on continuous evaluation against project objectives and milestones

• Effective project governance to exercise effective oversight of the project

• Protection of intellectual property rights to protect Government’s investments in the project

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Options for Future Development

• When the PBMR was defined in the mid 1990s it was based on the industrially demonstrated technology of the AVR and THTR reactors, as well as existing industrial gas turbines.

• The PBMR approach was to avoid any fundamentally new technologies and to move directly to the “demonstration” reactor which would by essentially a first of class of the commercial machine and while many tests were done to confirm the performance that the Germans had achieved, there were very few new design elements, except for the integration of the reactor with a helium gas turbine.

• One of the key elements of the PBMR work was the confirmation that fuel to the required specification could be built locally at NECSA, and in this aspect South Africa has been recognized as a world leader.

• Many lessons were learned from the development of the design of the PBMR and its nuclear licensing with the NNR. Given the now proven South African fuel performance and the technological advances since the original German work in the 1970s & 1980s, along with the revision to safety approaches, there is great potential to build on the PBMR technology base to achieve higher safety and economic performance.

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Options for Future Development

Possible New PBMR design (AHTR)

• Operating fuel temp limit at 1600oC (vs. 1130oC)

• Accident fuel temp limit at 2100oC (vs. 1600oC)

• Gas outlet at over 1200oC (vs. 900oC)

• Pebble bed heat transfer at 2100oC is 2.6 times that at 1600oC. (t14-t2

4)

• Central heat removal by Heat Pipes allows a concrete pressure vessel.

• With no blade cooling (CCC) then a thermal efficiency of 60% (similar to

modern CCGT) is achievable.

• Molten Salt system to extract heat for a combined cycle approach (560oC)

• Compared to the original PBMR the following is the impact:

• The DPP (400MW) has deltaT of 400oC and if the revised design has Tcold of 200oC

and Thot of 1200oC this leads to 1000MW with same geometry and flow rate.

• Power output of 600MWe (vs. 165MW)

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Options for Future Development – Power Plant

• To integrate the AHTR programme with the currently planned 9.6GW

PWR programme the following approach is proposed:

• Initial 2 year phase to establish the potential of specific technologies at a research level. These

could include: carbon-carbon turbo machinery, heat exchanges and structures, heat pipes,

molten salts, pre-stressed concrete pressure vessels, and advanced fuel handling systems.

• In parallel with the research phase there would be a 3 year program to design and obtain

permits (EIA, NNR etc) for a “proof of concept” reactor that would be some 100MWth/50MWe to

confirm the performance of the advanced technologies developed in the initial phase. In the

same period the concept design and business case for full scale commercial reactors, using

these technologies, would be developed.

• It is expected that after these are complete some 5 years would be needed for the construction

and commissioning of the “proof of concept” plant, along with finalisation of the commercial

design.

• This would allow an informed decision in the mid- 2020s as to whether the follow on from the

9.6GW PWR programme would be more PWRs or advanced PBMRs.

• The other programme would be the reestablishment of the operation of the PBMR fuel

laboratories at Pelindaba

Initial Scope of Technical Work

• Review the historical data from PBMR and review the lessons learned.

• Review the original User Requirement Specification and Safety Case logic.

• Establish the status of current test facilities and the fuel laboratories at NECSA’s Pelindaba site.

• Re-establish the fuel manufacturing laboratories at Pelindaba.

• Contract for finalisation of the post-irradiation examination of RSA manufactured fuel in the USA.

• Review fuel design options for more advanced Coated Particle fuel (including Thorium).

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Reviews and Information Gathering

• Status of carbon-carbon composites and other ceramics

• Graphite life expectation at higher flux and temperature than original PBMR operating point

• Potential for Heat pipes and other passive heat transfer options

• Iron Cast vs PCRV options

• Molten Salts Applications

• High temperature Helium/Molten Salt heat exchangers (500-750degC)

• Very High Temperature Control Rod options

• Licensing Framework and Safety Case Logic

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Current concept

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PCRV Based Concept

100 MWth

dT= 920 C

M= 20.9

kg/s

P= 40 bar abs

m= 20.9 kg/s

d= 1.3𝑘𝑔/ m3

Q=15.6 m3/s

s=30 m/s

Dpipe = 0.814 m Eturb(th)=56MW

dT= 520 C

P= 15 bar(

abs)

m= 20.9 kg/s

δ = 0.75𝑘𝑔/

m3

Q=27.8 m3/s

s=30 m/s

Dpipe(eqv) =

1.08 m

Eturb(mech)=50M

W ECO2(Hx)=19.5M

W

dT= 180 C

P= 15 bar (abs)

m= 20.9 kg/s

δ = 1.06𝑘𝑔/ m3

Q=19.7 m3/s

s=30 m/s

Dpipe(eqv) = 0.914

m

P= 15 bar

(abs)

m= 20.9 kg/s

δ = 0.93𝑘𝑔/

m3

Q=22.4 m3/s

s=30 m/s

Dpipe(eqv) =

0.97 m

Ems(Hx)=20MW,dT=

180 C

Erec)=18.4MW

dTprim (LP)=

170 C

dTsec (HP)=

160 C

P= 15 bar (abs)

m= 20.9 kg/s

δ = 1.79𝑘𝑔/m3

Q=11.67m3/s

s=30 m/s

Dpipe(eqv) = 0.7m

EPC(Hx)=10.8MW

dT= 100 C

P= 15 bar (abs)

M= 20.9 kg/s

δ = 2.37𝑘𝑔/m3

Q=8.8m3/s

s=30 m/s

Dpipe(eqv) = 0.61m

Ecomp)=10MW

dT= + 90 C

Egen (mech)=40MW

Egen( electric)=35 MW

Eelectric output )=35 MW

P= 40 bar (abs)

m= 20.9 kg/s

δ = 3.5𝑘𝑔/ m3

Q=5.97m3/s

s=30 m/s

Dpipe(eqv) = 0.5m

P= 40bar (abs)

m= 20.9 kg/s

δ = 4.7𝑘𝑔/ m3

Q=4.44m3/s

s=30 m/s

Dpipe(eqv) = 0.43m

t1

t2

t3

t4 t5

t6

t7

t8

t1=

t2= t3= t4= t5=

t6= t7=

t8=

t

s AHTR: Max pressure =40 bar

(abs) process ( first order)

• Pressure ratio for turbine is taken as

2.6

• Simple formule W=Q.dP to

determine outlet pressure gives

wrong answers ( dP as 35 atm)?

• T-S curve of helium needed.

• Pressure drop from friction ignored

E turbine and comp=

m.cp.dT

Average Power Density

= 5 𝑀𝑊/m3 of fuel

Total volume of fuel =

20m3

Thank you