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IN REPLY PLEASE REFER TO: M2.05 E.157-USA                                                                                                                                                                          DIAL DIRECTLY TO EXTENSION: +43 1 2600-21879
PRIERE DE RAPPELER LA REFERENCE:                                                                                                                                                                                  COMPOSER DIRECTEMENT LE NUMERO DE POSTE:                                                                                                                           

                                 2008-06-11

Subject:  IAEA Task USA E.01715 (POTAS Task E.157)
"Development of a Universal Non-destructive Assay Data Acquisition Platform"

Dear Ms. Hoffheins,

The development of the Universal NDA Data Acquisition Platform (UNAP) is the centrepiece of IAEA modernization of its NDA data acquisition instruments.  The principal reasons justifying the development of the UNAP have already been discussed, and we hope the SSTS has found them convincing. 

At this juncture, we intend to use the opportunity of redesigning issues that have persistently been problematic for unattended NDA systems.  One such problem is the concern for single event upsets (SEU) that can occur in digital electronics in the presence of energetic neutron fluxes.  None of the existing NDA instruments has been designed to mitigate the SEU problem.  The NGSS system has addressed this problem, and the NGSS system has a credible approach to mitigating the SEU problem for the application of video imaging.  Unfortunately, the problem is more severe for the NDA application than for the video application.  A single event upset is more damaging to NDA data acquisition than for video because NDA data must be acquired continuously.  If there is a loss of NDA data there is a loss of the continuity of knowledge.  Therefore, the mechanism used for NGSS is appropriate for that system, but would be insufficient for the UNAP.

The revised specification for the UNAP requires the necessary engineering to mitigate the SEU problem in that system.  However, to make absolutely sure that we are properly designing the system, we require a particular test.  We would like Los Alamos National Laboratory to perform this test.  The level of effort is estimated at about 1 man week of work.  There are no consumable supplies.

The test involves placing a neutron source, one of the ²⁵²Cf sources that are commonly available, in close proximity to the reference design board of the Vertex V5 processor that is the likely candidate for the UNAP system.  The processor board should be running a quick test program that simply cycles through memory.  Then, the experiment should measure whether, or how quickly, an SEU event disrupts the operation.  This test should be repeated to obtain stable statistics.  I would also like it repeated with about 4 different thicknesses of polyethylene shielding up to about 4 cm. to determine the mitigating effects of the polyethylene shielding.

The IAEA is therefore requesting assistance through POTAS Task E.157 to provide support from Los Alamos National Laboratory to perform this test.

The IAEA appreciates the continuing support provided by the US Support Programme to the Agency's safeguards efforts.

                                                                             Yours sincerely,

 

                           N. Khlebnikov

                           Director
                           Division of Technical Support

                           Department of Safeguards