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Cover gas purification experience at KNK

Abstract

KNK II is an experimental, sodium cooled fast breeder reactor. The reactor was operated until 1974 with a thermal core (KNK I). The plant was converted into a fast breeder reactor (KNK II) from 1974 to 1977. The commissioning of KNK II was started in October 1977 with the first fast core KNK 11/1. After 400 effective full power days (EFPD) the reactor was shut down in August 1982. After replacing the complete core by the second fast core KNK 11/2, the plant went into operation again in August 1983. In August 1986 nearly 400 EFPD were achieved with the second fast core. Argon is used as cover gas in the primary and secondary sodium systems of KNK. In former times fresh argon was supplied by a bundle of gas cylinders. Later on a liquid argon supply was installed. Purification of cover gas is done by flushing only. During KNK I operation no fuel failures occurred. The primary cover gas activity was characterized by the formation of Ar-41, only small quantities of fission gas were measured, released from 'tramp uranium'. Therefore, no problems existed during KNK I operation with regard to radioactive gas disposal. However, after start-up of KNK II,  More>>
Authors:
Richard, H; Stade, K Ch; [1]  Stamm, H H [2] 
  1. Kernkraftwerk-Betriebsgesellschaft m.b.H., Eggenstein-Leopoldshafen (Germany)
  2. Institute of Radiochemistry, Nuclear Research Center, Karsruhe (Germany)
Publication Date:
Jul 01, 1987
Product Type:
Conference
Report Number:
IWGFR-61
Resource Relation:
Conference: IAEA-IWGFR specialists' meeting on fast reactor cover gas purification, Richland, WA (United States), 24-26 Sep 1986; Other Information: 4 figs, 4 tabs; PBD: 1987; Related Information: In: Specialists' meeting on fast reactor cover gas purification, 288 pages.
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; ARGON; CLADDING; COVER GAS; FISSION PRODUCTS; FUEL ELEMENT FAILURE; HYDROGEN; KNK-2 REACTOR; NITROGEN; PRIMARY COOLANT CIRCUITS; PURIFICATION; REACTOR PROTECTION SYSTEMS; REACTOR SAFETY; SECONDARY COOLANT CIRCUITS; SODIUM; STEELS; ZIRCONIUM HYDRIDES
OSTI ID:
20236818
Research Organizations:
International Atomic Energy Agency, International Working Group on Fast Reactors, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
TRN: XA0200820011383
Availability:
Available from INIS in electronic form
Submitting Site:
INIS
Size:
page(s) 78-101
Announcement Date:

Citation Formats

Richard, H, Stade, K Ch, and Stamm, H H. Cover gas purification experience at KNK. IAEA: N. p., 1987. Web.
Richard, H, Stade, K Ch, & Stamm, H H. Cover gas purification experience at KNK. IAEA.
Richard, H, Stade, K Ch, and Stamm, H H. 1987. "Cover gas purification experience at KNK." IAEA.
@misc{etde_20236818,
title = {Cover gas purification experience at KNK}
author = {Richard, H, Stade, K Ch, and Stamm, H H}
abstractNote = {KNK II is an experimental, sodium cooled fast breeder reactor. The reactor was operated until 1974 with a thermal core (KNK I). The plant was converted into a fast breeder reactor (KNK II) from 1974 to 1977. The commissioning of KNK II was started in October 1977 with the first fast core KNK 11/1. After 400 effective full power days (EFPD) the reactor was shut down in August 1982. After replacing the complete core by the second fast core KNK 11/2, the plant went into operation again in August 1983. In August 1986 nearly 400 EFPD were achieved with the second fast core. Argon is used as cover gas in the primary and secondary sodium systems of KNK. In former times fresh argon was supplied by a bundle of gas cylinders. Later on a liquid argon supply was installed. Purification of cover gas is done by flushing only. During KNK I operation no fuel failures occurred. The primary cover gas activity was characterized by the formation of Ar-41, only small quantities of fission gas were measured, released from 'tramp uranium'. Therefore, no problems existed during KNK I operation with regard to radioactive gas disposal. However, after start-up of KNK II, several fuel elements failed. Until August 1986, five fuel failures were observed, two in KNK 11/1, and three in KNK 11/2. Sometimes, operation with defective fuel pins caused problems when fission gases leaked into the containment atmosphere, and the access had to be restricted. The purging rate of the primary cover gas was limited by the capacity of the charcoal filters in the delay line. Of all non-radioactive impurities, hydrogen (H{sub z}) and nitrogen (N{sub 2}) were of most importance in the primary cover gas. Main source of both impurities was the ingress of air and atmospheric moisture during handling operations in shutdown periods. An other possible source for hydrogen might be a release from the steel-clad zirconium hydride, used as moderator in the moderated driver fuel elements. Additional nitrogen may diffuse through the freeze seals of the primary valves located in the nitrogen-filled 'primary cell' of the plant.}
place = {IAEA}
year = {1987}
month = {Jul}
}