Technology Development

“The improvement of an excellent design”

Technology development is required to enhance the passive and safety attributes of the pebble bed modular reactor; to make it environmentally more attractive; to provide means to measure the hottest fuel temperature; and to improve the performance characteristics of the fuel.

TEST FACILITIES

PBMR’s test facilities are critical to effective licence approval and design maturity of the reactor and fuel plant. The progress of facilities is tangible and practical evidence of PBMR’s engineering, design and operational maturity.

Helium Test Facility (HTF)

The HTF was designed and constructed to provide a high-temperature, high-pressure helium environment. The HTF’s operational programme started on 26 March 2007. The HTF will enable the first full-scale operating tests of the critical components of the reactivity control system, reserve shutdown system and fuel-handling system. Active components such as valves and measuring equipment will be tested at high temperatures in a high-pressure helium environment, simulating reactor operating conditions. These tests will provide crucial and early feedback on the performance of equipment designed and built for the high-temperature and high-pressure helium environment. This facility will primarily be used for the pre-qualification and design verification testing of the main support systems planned for the PBMR demonstration power plant at Koeberg. This facility will run more than 200 tests of which 13 were conducted during the past year.

Heat Transfer Test Facility (HTTF)

The HTTF consists of a HPTU and a High-Temperature Test Unit (HTTU). These units will perform high-pressure and high-temperature core heat transfer tests. These heat transfer tests will validate heat transfer correlations used in the analyses done to determine the heat transfer in and from the core during normal conditions as well as following upset events. These thermohydraulic core calculations have laid the platform for the design optimisation and component design specifications of the PBMR’s Brayton thermodynamic cycle. The HPTU at the Potchefstroom campus of the North-West University was commissioned in September 2007. The supplier operated the facility on behalf of PBMR. The unit was decommissioned after completion of the scope of work in March 2008. The HTTU was commissioned in September 2006 and is operated by a supplier on behalf of PBMR on the North-West University site.

Fuel Development Laboratories

The Fuel Development Laboratories are situated on the Necsa site and are being operated under the Necsa nuclear licence. They consist of four laboratories, kernel, casting fuel-coating sphere manufacturing and quality control (QC) laboratories.

The Fuel Development Laboratories have transferred and fully established the German HTR fuel manufacturing and QC technology in its laboratories. The laboratories are in the process of producing advance fuel, scheduled to be completed by November 2008, provided the NNR approvals are granted in the anticipated time.

The objective beyond the advance irradiation fuel is to train future operational employees for the PFP, perform development tests on the processes and equipment for a commercial fuel plant and to support fuel characterisation activities.

During the past year, the most important milestones achieved were the commencement of hot commissioning of the ACF with depleted uranium and the import of 9,6% uranium powder for the advance fuel. The kernel laboratory processes have been fully qualified and are ready to produce the advance fuel as soon as the NNR approval is granted for operating with enriched uranium.

INTELLECTUAL PROPERTY (IP)

In terms of IP, PBMR aims to keep a balance between trade secrets and registered patents in managing its intellectual capital. This is consistent with the approach of the main nuclear companies globally. Patents will be secured if there are key elements in reactor systems, and engineering and operating reactors; fuel and waste processing; and probably digital control of reactor systems.

The current portfolio contains 11 active patent families with the potential for a further two based on the filing of provisional patents currently. A patent family is a set of patents in various jurisdictions based on one initial filing.

The earliest filing date is in 1999 and the most recent filing was 2004.

The patenting has moved with the project focus from reactor systems, operations and engineering and related inventions (up to early 2004) to fuel, isotope separation and waste processing in recent applications.

The University of Stellenbosch and PBMR entered into a Technology Development Agreement. Here are the CEO of PBMR, Jaco Kriek (left), and the Rector and Vice-Chancellor of the US, Prof Russel Botman.

The Rector of the University of Stellenboch, Prof Russel Botman, said that the contract fits in with the university’s commitment to the ideals of the United Nation’s Millennium Development Goals, especially with regard to ensuring a sustainable ecology. He said the university was “happy” to be a partner in this national programme directed at the provision of safe and sustainable energy for South Africa and worldwide. Many top-quality postgraduate students will be trained during the research programme, thereby providing the much-needed human capital for the nuclear and other sophisticated industries in our country.

AREAS OF TECHNOLOGY DEVELOPMENT

PBMR’s areas of technology development are focused on improving an excellent design, and the following areas of development are currently in progress:

TECHNOLOGY DEVELOPMENT
The various areas of technology development and PBMR’s co-working organisations are reflected in the table.

Area of technology development	Co-working organisation
Nuclear waste minimisation
Reclaiming of irradiated graphite from spent fuel and	•	Nesca*
reflector material by using a novel bacteriological	•	University of Pretoria*
method that will remove Carbon-14.	•	University of the Witwatersrand**
Remaining nuclides can be removed by chemical	•	North-West University**
means. Benefit would be a large reduction in nuclear	•	Participate in a European Union (Framework 7)
waste volume and possible reuse of reclaimed graphite.		project known as “CarboWaste”*
Fuel development/improvement
Focus on improving coating materials (SiC) and	•	Nesca*
predictive modelling of fuel characteristics under certain	•	University of Pretoria*
operational and accident conditions. Specific focus is	•	Nelson Mandela Metropolitan University* (NMMU)
the use of the advanced cluster computer at UP	•	University of the Witwatersrand**
(molecular modelling) and the further new High
Resolution Transmission Electron Microscope of NMMU.
Magnetic scrubber
Research initially focused on attempting to scrub	•	University of Stellenbosch*
silver. Now more focused on work supporting	•	iThemba LABS*
understanding of plate-out characteristics of silver.
Fuel temperature measurement
Development of a novel temperature measurement	•	Nesca**
solution that will enable the measurement of fuel	•	University of Stellenbosch*
temperature in real time under operational conditions	•	North-West University*
in the reactor core.
Passive cooling systems
Development of passive cooling systems solutions that use natural heat transfer processes to remove heat from the reactor core and spent fuel tanks. These require no active energy such as pumps. Also researching the possibility to use waste heat from the reactor to generate energy.	•	University of Stellenbosch*
Materials improvement
Wide-ranging materials research, eg improving graphite	•	University of Pretoria*
life expectancy, heat-resistant concrete, possible use	•	University of Cape Town**
of local coke in the manufacture of graphite, etc.	•	Nelson Mandela Metropolitan University*

*These universities/companies are currently actively engaged. A body of post-graduate students is also involved.
**These universities/companies are either planned to participate in next phases of these projects or are in the process of being contracted.