TY - JOUR
T1 - Separation of boric acid from PWR waste by volatilization during evaporation
AU - Bruggeman, A.
AU - Braet, J.
AU - Smaers, F.
AU - De Regge, P.
PY - 1997
Y1 - 1997
N2 - SCK·CEN has developed a process to separate boric acid during and/or after evaporation of the liquid waste from pressurized light-water reactors. The key goal is to achieve higher waste volume reduction factors, while maintaining low activity discharge limits. An additional goal is to obtain purified boric acid for recycling. The process is based on the volatility of boric acid in steam. The liquid waste is treated in a semi continuous evaporator, which operates preferentially at a higher temperature than the present evaporators. The stream loaded with boric acid is fed to a column for fractional condensation with partial reflux. In this way, one obtains a highly concentrated waste that contains all the radioactive and chemical impurities and little boron, a concentrated boric acid solution which can be reused, as well as a highly decontaminated effluent without boron. In case replacement or adaptation of existing evaporators is less practical, one can adapt the process for the treatment of evaporator concentrates. After having been intensively tested at SCK·CEN, the process has recently been demonstrated in a small pilot installation and with realistic liquid waste, at the nuclear power station in Doel, Belgium. The results corresponded to the theoretical predictions. After a transitional period, the boron concentration in the evaporator no longer increased and consequently did not limit the achievable waste volume reduction factor. The boric acid was recovered from the steam and during a supplementary treatment we recovered additional boric acid from the waste concentrate.
AB - SCK·CEN has developed a process to separate boric acid during and/or after evaporation of the liquid waste from pressurized light-water reactors. The key goal is to achieve higher waste volume reduction factors, while maintaining low activity discharge limits. An additional goal is to obtain purified boric acid for recycling. The process is based on the volatility of boric acid in steam. The liquid waste is treated in a semi continuous evaporator, which operates preferentially at a higher temperature than the present evaporators. The stream loaded with boric acid is fed to a column for fractional condensation with partial reflux. In this way, one obtains a highly concentrated waste that contains all the radioactive and chemical impurities and little boron, a concentrated boric acid solution which can be reused, as well as a highly decontaminated effluent without boron. In case replacement or adaptation of existing evaporators is less practical, one can adapt the process for the treatment of evaporator concentrates. After having been intensively tested at SCK·CEN, the process has recently been demonstrated in a small pilot installation and with realistic liquid waste, at the nuclear power station in Doel, Belgium. The results corresponded to the theoretical predictions. After a transitional period, the boron concentration in the evaporator no longer increased and consequently did not limit the achievable waste volume reduction factor. The boric acid was recovered from the steam and during a supplementary treatment we recovered additional boric acid from the waste concentrate.
UR - http://www.scopus.com/inward/record.url?scp=0030978712&partnerID=8YFLogxK
U2 - 10.1080/01496399708003227
DO - 10.1080/01496399708003227
M3 - Article
AN - SCOPUS:0030978712
SN - 0149-6395
VL - 32
SP - 737
EP - 757
JO - Separation Science and Technology
JF - Separation Science and Technology
IS - 1-4
ER -