A sealing arrangement of a protruding bar (1) arranged to enter into a combustion chamber (3) of the boiler through an opening (5) of a wall (4) of the combustion chamber (3). The protruding bar (1) is attached to a handling device (10). The sealing arrangement has a gasket (2) for sealing the opening (5). The gasket (2) is slidably arranged around the protruding bar (1) for sealing a gap between the protruding bar (1) and the wall (4) of the combustion chamber so that sealing arrangement is configured to keep the gasket (2) attached to the wall (4) of the combustion chamber (3) while the protruding bar (1) is fully inserted into the combustion chamber (3) and at least a part of time when the protruding bar (1) enters into the combustion chamber (3) and at least a part of time when the protruding bar (1) retracts from the combustion chamber (3).

A two step process for the destruction of a precursor material using a steam plasma in a three zone reactor wherein the precursor material is hydrolyzed as a first step in the high temperature zone of the reactor, followed by a second step of medium temperature oxidation of the reactant stream in the combustion zone of the reactor where combustion oxygen or air is injected and immediate quenching of the resulting gas stream to avoid the formation of unwanted by-products. A related apparatus includes a non transferred direct current steam plasma torch, an externally cooled three zone steam plasma reactor means for introducing the precursor material into the plasma plume of the plasma torch, means for introducing the combustion air or oxygen into the combustion zone, means for exiting the reactant mixture from the reactor and means for quenching the reactant mixture located at the exit end of the reactor.

A two step process for the destruction of a precursor material using a steam plasma in a three zone reactor wherein the precursor material is hydrolyzed as a first step in the high temperature zone of the reactor, followed by a second step of medium temperature oxidation of the reactant stream in the combustion zone of the reactor where combustion oxygen or air is injected and immediate quenching of the resulting gas stream to avoid the formation of unwanted by-products. A related apparatus includes a non transferred direct current steam plasma torch, an externally cooled three zone steam plasma reactor means for introducing the precursor material into the plasma plume of the plasma torch, means for introducing the combustion air or oxygen into the combustion zone, means for exiting the reactant mixture from the reactor and means for quenching the reactant mixture located at the exit end of the reactor.