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Feed water distribution pipe replacement at Loviisa NPP

Abstract

Imatran Voima Oy operates two WWER-440 reactors. Unit 1 has been operating since 1977 and unit 2 since 1981. First damages of feed water distribution (FWD) pipe were observed in 1989. The FWD-pipe T-connection had suffered from severe erosion corrosion damages. Similar damages have been been found also in other WWER-440 type NPPs. In 1989 the nozzles of the steam generator YB11 were inspected. No signs of the damages or signs of erosion were detected. The first damaged nozzles were found in 1992 in steam generators of both units. In 1992 it was started studying different possibilities to either repair or replace the damaged FWD-pipes. Due to the difficult conditions for repairing the damaged nozzles it was decided to study different FWD-pipe constructions. In 1991 two new feedwater distributors had been implemented at Dukovany NPP designed by Vitckovice company. Additionally OKB Gidropress had presented their design for new collector. In spring 1994 all the six steam generators of Rovno NPP unit 1 were replaced with FWD-pipes designed by OKB Gidropress. After the implementation an experimental program with the new systems was carried out. Due to the successful experiments at Rovno NPP Unit 1 it was decided to implement `Gidropress solution`  More>>
Authors:
Savolainen, S; Elsing, B [1] 
  1. Imatran Voima Loviisa NPP (Finland)
Publication Date:
Dec 31, 1995
Product Type:
Conference
Report Number:
LTKK-TJ-43; CONF-9410509-
Reference Number:
SCA: 210200; 360105; PA: AIX-29:032377; EDB-98:066406; SN: 98001970784
Resource Relation:
Conference: 3. international seminar on horizontal steam generators, Lappeenranta (Finland), 18-20 Oct 1994; Other Information: PBD: 1995; Related Information: Is Part Of Third international seminar on horizontal steam generators; PB: 430 p.
Subject:
21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS; 36 MATERIALS SCIENCE; CORROSION; EROSION; FEEDWATER; INSPECTION; PIPES; REACTOR MAINTENANCE; REACTOR SAFETY; STEAM GENERATORS; WWER TYPE REACTORS
OSTI ID:
614755
Research Organizations:
Lappeenranta Univ. of Technology (Finland).
Country of Origin:
Finland
Language:
English
Other Identifying Numbers:
Other: ON: DE98626444; ISBN 951-763-942-2; TRN: FI9800093032377
Availability:
INIS; OSTI as DE98626444
Submitting Site:
FIN
Size:
pp. 385-398
Announcement Date:

Citation Formats

Savolainen, S, and Elsing, B. Feed water distribution pipe replacement at Loviisa NPP. Finland: N. p., 1995. Web.
Savolainen, S, & Elsing, B. Feed water distribution pipe replacement at Loviisa NPP. Finland.
Savolainen, S, and Elsing, B. 1995. "Feed water distribution pipe replacement at Loviisa NPP." Finland.
@misc{etde_614755,
title = {Feed water distribution pipe replacement at Loviisa NPP}
author = {Savolainen, S, and Elsing, B}
abstractNote = {Imatran Voima Oy operates two WWER-440 reactors. Unit 1 has been operating since 1977 and unit 2 since 1981. First damages of feed water distribution (FWD) pipe were observed in 1989. The FWD-pipe T-connection had suffered from severe erosion corrosion damages. Similar damages have been been found also in other WWER-440 type NPPs. In 1989 the nozzles of the steam generator YB11 were inspected. No signs of the damages or signs of erosion were detected. The first damaged nozzles were found in 1992 in steam generators of both units. In 1992 it was started studying different possibilities to either repair or replace the damaged FWD-pipes. Due to the difficult conditions for repairing the damaged nozzles it was decided to study different FWD-pipe constructions. In 1991 two new feedwater distributors had been implemented at Dukovany NPP designed by Vitckovice company. Additionally OKB Gidropress had presented their design for new collector. In spring 1994 all the six steam generators of Rovno NPP unit 1 were replaced with FWD-pipes designed by OKB Gidropress. After the implementation an experimental program with the new systems was carried out. Due to the successful experiments at Rovno NPP Unit 1 it was decided to implement `Gidropress solution` during 1994 refueling outage into the steam generator YB52 at Loviisa 2. The object of this paper is to discuss the new FWD-pipe and its effects on the plant safety during normal and accident conditions. (orig.).}
place = {Finland}
year = {1995}
month = {Dec}
}