The operations and use of a
certain number of systems require authorizations granted by safety authorities.
The issuance of these
authorizations is based on safety demonstrations.
In aeronautics, onboard systems must
satisfy airworthiness requirements.
These certificates are granted
on the basis of satisfactory proof that demonstrates that the air transport
system fulfills the specifications at least to the level required by defined
standards (FAA, CAA, DGAC …). The basis for the proof in particular
includes failure analyses, plans and trial results.
In the
field of nuclear energy, plant operations are subject to authorizations granted
by the Nuclear Safety Authority (Autorité de Sûreté Nucléaire) pursuant
to procedures that include the designer’s and operator's safety reports that
must demonstrate the safety of the installation designed or used.
Similar terms apply to other
sectors (rail transport, space, oil and chemical industries …).
Execution and Support
ClearSy provides support in the
management of all the works related to safety demonstrations pursuant to the
standards applicable in the field. They cover material and software features
for the relevant system:
- Preliminary risk analysis
- Analysis of the principles of the architecture’s
safety
- FMAEC
- ASEE
- Critical code reading
- Safety analysis of code chain production safety
- Safety dossiers
and are performed in various
contexts:
- Support to manufacturers
- Support to the bodies responsible for certification
This support has been specifically
provided for critical systems (Safety Integrity Level 4):
- SBKL TIVD railway signal system
- MF 2000 rolling stock safety system
- Computerized control stations parameterization
software
- Coding and extension software
Formal Demonstration
As an alternative to traditional
methods, Clearsy consultants have
perfected a formal demonstration method for operational principles, in
particular applied to protection and backup systems, in collaboration with J.R.
Abrial, the inventor of the B Method.
This formal demonstration method guarantees the soundness of these systems with
defined incidental and accidental hypotheses and also provides a secure means
to diagnose failures and their effects.
This formal demonstration acts
as a complement to calculations, simulations and trials that are conducted in
parallel.
This formal method has been used
in the context of:
