INB’s uranium enrichment plant: testing and installation of the DMOSS surveillance system by the ABACC
Luis Rovere and
Hugo Vicens
Immediately after the first negotiation meeting aimed at establishing
the safeguards approach for the isotopic enrichment commercial plant of
Indústrias Nucleares do Brasil (INB), the ABACC was in charge of
providing the surveillance system to be installed in that facility, following
the directions set forth in the “guidelines for the coordination of
inspection activities between the ABACC and the IAEA” approved in
1997.
In order to comply with this task, the ABACC had to select
the surveillance system, perform the laboratory operational
tests and install the system before the start of the routine
operation of the first cascade of the plant, whose licensing
process had been scheduled for the first semester in 2004.
The selection of the surveillance system was quite complex because, when
the negotiations were started, there was not a clear picture of the safeguards
measures that would be applied in the facility. The spectrum of possibilities
was very broad because it depended on the configuration conditions. On the
other hand, there was a need to install the surveillance system at the feed
and withdrawal facility, as well as to establish the necessary measures
to strengthen unannounced access to the cascade hall. These two situations
led to highly different alternatives, such as the implementation of a permanent
perimeter, unannounced accesses with transitory perimeter or permanent control
of strategic points and/or only restricted to the permanence of the inspectors
during unannounced inspections.
In addition to these alternatives, there was a need to consider
the fact that, throughout several years, there would be cascades
in routine operation parallel to others still in their licensing
and construction stages, as well as the probability that,
in addition to a permanent feed and withdrawal station, there
would be a smaller temporary station operating, simultaneously,
with its associated strategic points. Considering that this
was an evolving project, some of the operational criteria
would remain under discussion in an attempt to find solution
to optimize the routine operation through the addition of
new cascades.
In spite of the lack of definitions, there were five features of the surveillance
system that were neatly clear:
- the system had to be very reliable because, in this
type of facilities, in case of loss of surveillance, the
re-verification of the cylinders would not restore knowledge
in a way allowing to cover all the deviation scenarios;
- the system had to be capable for remote transmition
of its state of health, as a minimum;
- the storage capacity had to be appropriate for any of
the possible alternatives;
- the system had to support, at least, five or six cameras
set up in different operating modes;
- the system configuration had to be versatile enogh
to allow for any of the potential configuraitons.
In order to select the system, the ABACC chose the hipothesis
of a continuous perimeter, including cameras at the main gate
to capure, every ten seconds, all entrance and exit movements.
At the temporary feed and withdrawal station, two cameras
would be installed, while at the main station, VACOSS seals
(Variable Coding Seal System) would also be installed as containment
devices for process cylinders, connected to trigger the cameras.
Finally, the system would also have cameras connected to VACOOSS
seals in emergency exits.
The system pre-selected by the ABACC for the most conservative
conditions was the Digital Multi-Channel Optical System (DMOS),
considering that it included very versatile technical features,
such as:
- the use of DCM-14 (Digital Camera Module 14) type cameras,
which are highly reliable and in whose installation and
operation ABACC had a five-year experience;
- high system storage capacity, enough to store, as a
minimum, the information corresponding to two consecutive
surveillance periods in the server;
- maximum data redundancy. The system provides storage
capacity in the cameras’ flash memories, in the
redundant disc array, and in two independent DLT (Digital
Linear Tapes) tape units;
- the server is equipped with redundant power supplies.
Additionally, each of the camera management modules is
connected to different power supply busses, allowing the
cameras to remain energized, even in case of UPS (Uninterruptible
Power Supply) failure;
- the system’s software allows for remote monitoring
applications through the Windows NT’s remote access
service (RAS), which is compatible with several types
of communication hardware and network protocols;
- the server can generate file and directory structures
that allow image storage in different folders, with differentiated
periods, so as to satisfy the requirements for both interim
and unannounced inspections simultaneously, for those
cameras monitoring strategic points;
- the camera’s communication and power wires are
electrically isolated from the server;
- capability to connect a large number of cameras.
Before purchasing the equipment, ABACC asked Sandia National
Laboratory personnel to perform tests for a system equipped
with nine cameras triggered by a door opening/closing device.
It was also requested to test the system with some camaras
configured in ten-second and others in three-minute intervals,
and also to estimate the time required for their review. The
results obtained were satisfactory.
The ABACC purchased the system in 2003 and subjected it to
laboratory tests during one year —while the state of
health remote data transmission was also tested. At the same
time, the negotiation of the safeguards approach continued
and evolved until an approach was reached that does not require
any perimeter but in which the surveillance system plays a
very important role. In this new approach, the purchased system
does not imply any limitations to the cameras monitoring the
strategic points and will allow their connection with the
interface that records the closure and opening of the VACOSS
seals at the feed and withdrawal station, complying, simultaneously,
with the requirements of both the interim and unannounced
inspections; additionally, the number of cameras required
for the licensing of new cascades is not limited, while the
system is reliable and allows for a simple application of
remote data transmission.
The system was installed at the facility in early 2005. By
October, the six-month period for field tests, required for
its routine use for safeguards purposes, will have elapsed.
On the other hand, in September this year, the first cascade
will start its routine operation. The ABACC achieved its initial
goal of installing and commissioning the DMOS. Now, the expectations
are that, in the future, the results will confirm the virtues
of the system.
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The Denuclearization Agreements and the Future
by››› Marco
A. Marzo |
