Decontamination of liquid-metal fast breeder reactor components for reuse; The French experience

Journal Article · Fri Feb 01 00:00:00 EST 1991 · Nuclear Technology; (United States)

OSTI ID:5080101

Michaille, P ^[1]; Moroni, J C ^[2]; Lambert, I ^[3]

---

1. Commissariat a l'Energie Atomique, Centre d'Etudes Nucleaires Cadarache, 13108 St. Paul-lez-Durance (FR)
2. Commissariat a l'Energie Atomique Centrale Phenix, 30205 Bagnols-sur-Ceze (FR)
3. Commissariat a l'Energie Atomique, Centre d'Etudes Nucleaires, 92265 Fontenay-aux-Roses (FR)

Decontamination of stainless steel liquid-metal fast breeder reactor components for reuse in France began with the decontamination of Rapsodie components. At that time, dilute phosphoric acid was used. To cope with additional irradiated components after Phenix came into operation, an extensive study was performed, which led to the selection of a procedure involving two baths. The first bath, alkaline permanganate (AP), is applied for 3 h; the second bath, sulfo-phosphoric acid (SP), is applied for 6 h, both at 60{degrees}C. Up to three cycles are repeated until the residual dose rate is sufficiently low. Eight intermediate heat exchangers (IHXs) and two primary pumps from Phenix were decontaminated using this method. This paper reports that because SP can pickle only a limited depth ({approximately} 3{mu}m), due to the passivation effect of phosphoric acid, and because of the waste treatment problems associated with phosphates, new solutions were explored. One possibility involves improvement of the AP-SP procedure: In the SPm procedure, the AP bath is omitted and the phosphoric concentration is reduced by a factor of 4. A second approach is the use of a new formula, called SECA, a mixture of maleic and citric acid used in reducing conditions (imposed by hydrazine). Since the Phenix and Superphenix waste treatment facilities are not designed to reprocess maleic-citric acid, only the SPm procedure has been used on reactor components. A low-contaminated IHX from Rapsodie served as a test benchmark, not only for the decontamination procedure, but also for the requalification criteria, before the SPm procedure was applied to a highly contaminated IHX from Phenix. Recent results are presented.

• OSTI ID: 5080101
• Journal Information: Nuclear Technology; (United States), Vol. 93:2; ISSN 0029-5450
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
REACTOR COMPONENTS
DECONTAMINATION
STAINLESS STEELS
BREEDER REACTORS
CITRIC ACID
LIQUID METAL COOLED REACTORS
MALEIC ACID
PASSIVATION
PHOSPHORIC ACID
REDUCTION
ALLOYS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CLEANING
DICARBOXYLIC ACIDS
HIGH ALLOY STEELS
HYDROGEN COMPOUNDS
HYDROXY ACIDS
INORGANIC ACIDS
IRON ALLOYS
IRON BASE ALLOYS
ORGANIC ACIDS
ORGANIC COMPOUNDS
REACTORS
STEELS
210500* - Power Reactors
Breeding