Method of ascertaining the state inside melting furnace for radioactive waste

Claim 1

A method of ascertaining the state inside a melting furnace for a radioactive waste, which method comprises the steps of: (1) blowing a gas into a molten matter in the melting furnace by using a least two slender tubes including a first tube opening into the furnace at an upper point thereof and a second opening into the furnace at a lower point thereof with a gap Δh between the upper and lower points; (2) detecting a back pressure difference ΔP at the openings of the first and second tubes to determine the density ρ of the molten matter in accordance with the following equation: ρ=ΔP/g.Δh where g is the gravitational acceleration; (3) detecting a minimum pressure P required for releasing gas bubbles into the molten matter from one of the at least two slender tubes; (4) determining the level h of the molten matter in the furnace using the density determined in step (2) and in accordance with the following equation: ##EQU2## where P O is the pressure on the surface of the molten matter, γ is the surface tension of the molten matter, and r is the radius of the one of the at least two slender tubes; (5) determining the relationship between a quantity of the waste charged into the melting furnace and the pressure P in a normal case where the charges waste is molten in the furnace; and (6) monitoring the pressure P to detect a shift of the pressure P from the relationship obtained in step (5) to thereby detect the formation of a bridge inside the furnace comprising non-molten solid matter of the charged waste.

Claim 2

A method of ascertaining the state inside a melting furnace for a radioactive waste, which method comprises the steps of: (1) blowing a gas into a molten matter in the melting furnace by using a least two slender tubes including a first tube opening into the furnace at an upper point thereof and a second opening into the furnace at a lower point thereof with a gap Δh between the upper and lower points; (2) detecting a back pressure difference ΔP at the openings of the first and second tubes to determine the density ρ of the molten matter in accordance with the following equation: ρ=ΔP/g.Δh where g is the gravitational acceleration; (3) detecting a minimum pressure P required for releasing gas bubbles into the molten matter from one of the at least two slender tubes; (4) determining the level h of the molten matter in the furnace using the density determined in step (2) and in accordance with the following equation: ##EQU2## where P O is the pressure on the surface of the molten matter, γ is the surface tension of the molten matter, and r is the radius of the one of the at least two slender tubes; (5) determining the relationship between a quantity of the waste charged into the melting furnace and the pressure P in a normal case where the charges waste is molten in the furnace; and (6) monitoring the pressure P to detect a shift of the pressure P from the relationship obtained in step (5) to thereby detect the formation of a bridge inside the furnace comprising non-molten solid matter of the charged waste.

Claim 5

A method of ascertaining the state inside a melting furnace for a radioactive waste, which method comprises the steps of: (a) blowing a gas into a molten matter in the melting furnace by use of a slender tube opening into the furnace; (b) detecting a minimum pressure P required for releasing gas bubbles into the molten matter from the slender tube; (c) determining the relationship between a quantity of the waste charged into the melting furnace and the pressure P in a normal case where the charged waste is molten in the furnace; and (d) monitoring the pressure P to detect the shift of the pressure P from that determined in step (c) to thereby detect the formation of a bridge inside the furnace comprising a non-molten solid matter of the charged waste when the shift is an increase in the pressure P, and to thereby detect a breakage of the bridge when the pressure P experiences a rapid decrease.

Claim 6

A method of ascertaining the state inside a melting furnace for a radioactive waste, which method comprises the steps of: (a) blowing a gas into a molten matter in the melting furnace by use of a slender tube opening into the furnace; (b) detecting a minimum pressure P required for releasing gas bubbles into the molten matter from the slender tube; (c) determining the relationship between a quantity of the waste charged into the melting furnace and the pressure P in a normal case where the charged waste is molten in the furnace; and (d) monitoring the pressure P to detect the shift of the pressure P from that determined in step (c) to thereby detect the formation of a bridge inside the furnace comprising a non-molten solid matter of the charged waste when the shift is an increase in the pressure P, and to thereby detect a breakage of the bridge when the pressure P experiences a rapid decrease.