SSRT for Hydrogen Water Chemistry Verification in BWRs

2009 ◽  
pp. 51-51-14 ◽  
Author(s):  
ME Indig
Keyword(s):  
Water Chemistry ◽  
Hydrogen Water

Oxide Film Characterization after the crack propagation in CT specimens of AISI 304L under Hydrogen Water Chemistry Condition.

2016 ◽  
Vol 1814 ◽  
Author(s):  
Ángeles Díaz Sánchez ◽  
Aida Contreras Ramírez ◽  
Carlos Arganis Juárez
Keyword(s):  
Oxide Film ◽  
Crack Propagation ◽  
Water Chemistry ◽  
Degradation Mechanism ◽  
Electrochemical Corrosion ◽  
General Term ◽  
Test Method ◽  
Feed Water ◽  
Aisi 304L ◽  
Hydrogen Water

ABSTRACTStress Corrosion Cracking (SCC) in a general term describing stressed alloy fracture that occurs by crack propagation in specifically environments, and has the appearance of brittle fracture, yet it can occur in ductile materials like AISI 304L used in internal components of Boiling Water Reactors (BWR). The high levels of oxygen and hydrogen peroxide generated during an operational Normal Water Condition (NWC) promotes an Electrochemical Corrosion Potential (ECP), enough to generate SCC in susceptible materials. Changes in water chemistry have been some of the main solutions for mitigate this degradation mechanism, and one of these changes is reducing the ECP by the injection of Hydrogen in the feed water of the reactor; this addition moves the ECP below a threshold value, under which the SCC is mitigated (-230mV vs SHE). This paper shows the characterization by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Raman Spectroscopy of the oxide film formed in to a crack propagated during a Rising Displacement Test method (RDT), on Hydrogen Water Chemistry (HWC) conditions: 20 ppb O2, 125 ppb H2, P=8MPa, T=288°C, using a CT specimen of austenitic stainless steel AISI 304L sensitized. The characterization allowed identifying the magnetite formation since an incipient way, until very good formed magnetite crystals.

Fundamental Mechanisms of Component Degradation by Corrosion in Nuclear Power Plants of Russian Design

2008 ◽  
Author(s):  
G. Saji ◽  
V. A. Yurmanov ◽  
V. I. Baranenko ◽  
V. A. Fedorova ◽  
G. Karzov ◽  
...  
Keyword(s):  
Power Systems ◽  
Water Chemistry ◽  
Steam Generator ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Electrochemical Characteristics ◽  
Secondary System ◽  
Technological Basis ◽  
Hydrogen Water

By focusing on NPPs of Western design (e.g. PWR and BWR), the first author (G. Saji) has established that ‘long cell action’ corrosion plays a pivotal role in practically all unresolved corrosion issues for all types of nuclear power plants as presented in a series of papers already published (1–9). The authors believe that a similar study of NPPs of Russian design, with their unique scientific and technological basis compared to Western plants, are important to illustrate that this mechanism can occur even with different materials, welding technology or operation (e.g. water chemistry control). Among all the differences, it is important to note that PWSCC per se does not seem to be occurring in VVER plants, although no specific reason has yet to be identified. In this paper, a detailed electrochemical assessment is first made on the behavior of ammonia-potassium water chemistry and structural materials at the normal operational temperature in the primary water of VVERs. The chemical and electrochemical characteristics of the ammonia in VVERS were found to be significantly different from those of PWRs which use the hydrogen water chemistry. However, the water chemistry of RBMK is not fundamentally different from that of the Western BWR and therefore the previous studies on SCC of BWRs are generally applicable. On the bases of these studies, various corrosion issues commonly experienced in NPPs of Russian design (VVER and RBMK) are briefly reviewed. They include: (i) pitting corrosion in un-clad VVER-440 RV; (ii) corrosion cracking at the transition welding joints of RV nozzles and piping; (iii) corrosion issues in PGV-440 steam generator collectors; (iv) steam generator tube and collector corrosion; (v) IGSCC in RBMK with austenitic steel piping; (vi) FAC (E-C) in the secondary system of VVERs; and (vii) Anomalous corrosion products sedimentation in the core region in some VVERs. Since the long cell action hypothesis does not seem to contradict the various corrosion activities being experienced in NPPs of Russian design, the first author invites further study on the potential involvement of this mechanism since this hypothesis provides new insight into many of the unresolved corrosion issues. More specifically, the VVERs’ ammonia-potassium water chemistry has theoretically been identified as playing a key role in the prevention of PWSCC, which is one of the most troublesome mechanism of corrosion degradation in many Western PWRs. In view of this significance, the authors proposed an urgent international joint initiative to prove or disprove this mechanism’s existence in nuclear power systems.

scholarly journals Effect of Hydrogen Water Chemistry on Zircaloy-2 Fuel Cladding and Structure Material Performance

2006 ◽  
Vol 43 (9) ◽  
pp. 1021-1030 ◽  
Author(s):  
Sachio SHIMADA ◽  
Shinji ISHIMOTO ◽  
Toshio MATSUMOTO ◽  
Yoshiaki ISHII ◽  
Akihiro MIYAZAKI
Keyword(s):  
Water Chemistry ◽  
Fuel Cladding ◽  
Hydrogen Water

scholarly journals Development of Hydrogen Water Chemistry in Fugen Nuclear Power Station.

1993 ◽  
Vol 35 (1) ◽  
pp. 75-86 ◽  
Author(s):  
Takuya KITABATA ◽  
Takahisa NAKAMURA ◽  
Kazumi ANAZAWA ◽  
Fumito NAKAMURA
Keyword(s):  
Water Chemistry ◽  
Nuclear Power Station ◽  
Nuclear Power ◽  
Power Station ◽  
Hydrogen Water
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