Systems (NuTraSeal)
Within the framework of Nuclear Safeguards there is a demand for a robust and durable system of seals making possible the tracing and tracking, the monitoring, the identification and the verification over a period of several years of containers used either for the underwater storage of fissile materials to be reprocessed or for the transportation of nuclear fuel. The seals have to be radiation resistant and reliable even in very harsh environmental conditions. New solutions and improved designs are continuously requested by the inspection agencies. The NuTraSeal action provides technical support to the Euratom Treaty, to the Directorate General for Energy and Transport (DG TREN) and to the Interna- tional Atomic Energy Agency (IAEA) in the form of research development and deployment of sealing and identification equipment and of environmental and electromagnetic testing of inspector equipment in the SILab and TEMPEST laboratories.
The specific tasks are agreed with the customer in the framework of the JRC-DG TREN co-operation agreement and the EC Support Programme (SP-1) with the IAEA.
Major 2007 achievements
JRC CANDU Seals (JCS)
Up to now, IAEA has used ARC19 seals to secure underwater storage of spent
nuclear fuel bundles from CANDU20 type reactors, located at the Darlington
(Canada) and Cernavoda (Romania) power generation facilities. After a nearly twenty-year service life, the ARC seal is no longer easily manageable. For this reason IAEA urgently needed a reliable alternative sealing system for the various CANDU reactors throughout the world.
Within the framework of SP-1, IAEA asked JRC-IPSC to develop a new CANDU sealing system based on the ultrasonic one patented by JRC-IPSC and currently used in Sellafield and The Hague.
Designing the new seals required considerable efforts, but eventually the first JRC Candu Seals (JCS) were placed in the spent fuel pond of the Cernavoda reactor in June 2006. The very good results of this first sealing campaign encouraged IAEA to decide on replacing half of the existing ARC seals with JCS seals.
Every spent fuel bundle stack is sealed with two seals: one of them is a JCS seal and the second an ARC seal to assure continuity of knowledge. About thirty JCS seals were successfully installed during 2007 and the plan for the future is to install only JCS seals. In the meantime, a JCS sealing system with 50 seals and reading software were produced for a vulnerability assessment commissioned by IAEA to Sandia National Laboratory. The results will be made available by mid-2008. The design will be upgraded according to the findings of the vulner- ability assessment. A further supply of 100 seals for Cernavoda was required and will be delivered in 2008.
Contact Marco Sironi Tel. +39 0332 785754 e-mail: [email protected] website: http://silab.jrc.it/
N u Tr a S e a l
JRC Candu Seals (JCS) identities. JRC Candu Seals (JCS) reading system.
JRC Dry storage Seals (JDS)
Another line of development was to further rationalise the ultrasonic sealing concept and use it for new applications. IAEA and DG TREN requested the devel- opment of a system for long term dry storage (e.g. in CASTOR containers), which entailed a new design of seals, reading heads (able to read in dry conditions) and the development of remotely operated reading equipment.
A generic multi-purpose bolt seal for dry storage applications was designed. Its performance is the same as for the underwater bolt seal, but specific features were added to prevent the otherwise easy tampering due to the accessible position of the seal in dry storage. The new design fits Castor type containers (M24) but could be adapted to any dry storage container. A preliminary internal vulnerability assessment was carried out at JRC-IPSC to better show the limits of the design in relation with the cost benefits. A sealing system and 50 seals have been produced for a vulnerability assessment commissioned by IAEA to Sandia National Laboratory. The results will be made available by mid-2008 and the design will be upgraded accordingly.
Security of confidential documents related to inspections
IAEA and DG TREN are also investigating a more widespread use of the technology used in safeguards and requested the design of a solution for a management system for confidential/security documents (e.g. reports on inspections, etc.). A preliminary study was started at the end of 2007.
Challenges for the Future
NuTraSeal foresees an increased request for ultrasonic seals by IAEA. The target is to extend the sealing system used in Cernavoda to other Candu reactors. In 2008 a couple of hundreds seals and two reading systems for Candu are to be fabricated and delivered. The sealing systems for dry applications are also very promising. A custom application for a specific container is now under study. IAEA asked SILab to be the European reference laboratory for vulnerability as- sessment of inspecting equipment developed outside Europe.
A new specific task will be opened by IAEA to support the development and delivery of a system for secure storage of classified documents.
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Safeguards for Gas Centrifuge En- richment Plants
During 2007 PhyMod initiated a study to develop a Theoretical Centrifuge and Cascade Simulator (TCCS). Sev- eral numerical algorithms are under development to model centrifuges and corresponding cascade configu- rations. The models that are used are all based on a substantially grounded theory. The TCCS is designed in a flexible way and different types of centrifuges and cascades can be ana- lysed with it. The TCCS is mainly used in the field of country profiles for making rapid assessments of enrich- ment capacities. In particular, it has been applied for monitoring the evo- lution of the Iran capability following the installation of new centrifuges at the Natanz plant.
A Real-Time Mass Evaluation System (RTMES) is under development for the nuclear material accountancy verification in a gas centrifuge enrich- ment plant. The proposed RTMES analyses weight data that is collected continuously from the feed, tails and product stations. Real-time evalua- tion of these load cell data by mass balancing is an attractive proposition, because it is not intrusive. It neither looks inside the cascade hall nor impinges on plant operation. In addi- tion, the RTMES is Real Time system that is able to alert the safeguards inspectors if an issue is evolving. This is because the delays in present- ing the mass balance results will be extremely short relative to the IAEA timeliness criterion.