scholarly journals Study on History of Gate-Valve System

1996 ◽  
Vol 16 ◽  
pp. 145-157
Author(s):  
Seize TAKEBAYASHI ◽  
Akira WATANABE ◽  
Toshiharu NAKATA ◽  
Kouji KAWAI
Keyword(s):  
Gate Valve ◽  
Valve System ◽  
History Of

scholarly journals Plant Performance History of an Innovative Gate Valve in Critical Service Applications

2017 ◽  
Author(s):  
M. S. Kalsi ◽  
Patricio Alvarez ◽  
Thomas White ◽  
Micheal Green
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Gate Valve ◽  
Plant Performance ◽  
Flow Loop ◽  
Performance History ◽  
Pressurized Water ◽  
Maintenance Costs ◽  
History Of ◽  
Water Reactors

A previous paper [1] describes the key features of an innovative gate valve design that was developed to overcome seat leakage problems, high maintenance costs as well as issues identified in the Nuclear Regulatory Commission (NRC) Generic Letters 89-10, 95-07 and 96-05 with conventional gate valves [2,3,4]. The earlier paper was published within a year after the new design valves were installed at the Pilgrim Nuclear Plant — the plant that took the initiative to form a teaming arrangement as described in [1] which facilitated this innovative development. The current paper documents the successful performance history of 22 years at the Pilgrim plant, as well as performance history at several other nuclear power plants where these valves have been installed for many years in containment isolation service that requires operation under pipe rupture conditions and require tight shut-off in both Pressurized Water Reactors (PWRs) and Boiling Water Reactors (BWRs). The performance history of the new valve has shown to provide significant performance advantage by eliminating the chronic leakage problems and high maintenance costs in these critical service applications. This paper includes a summary of the design, analysis and separate effects testing described in detail in the earlier paper. Flow loop testing was performed on these valves under normal plant operation, various thermal binding and pressure locking scenarios, and accident/pipe rupture conditions. The valve was designed, analyzed and tested to satisfy the requirements of ANSI B16.41 [9]; it also satisfies the requirements of ASME QME 1-2012 [10]. The results of the long-term performance history including any degradation observed and its root cause are summarized in the paper. Paper published with permission.

The Social Origins and Provenance of the English Bishops during the Reign of Edward II

1959 ◽  
Vol 9 ◽  
pp. 51-79
Author(s):  
K. Edwards
Keyword(s):  
Middle Ages ◽  
Social Background ◽  
Early Career ◽  
The Political ◽  
Social Origins ◽  
Political Activities ◽  
Edward Ii ◽  
The Social ◽  
Complete Study ◽  
History Of

During the last twenty or twenty-five years medieval historians have been much interested in the composition of the English episcopate. A number of studies of it have been published on periods ranging from the eleventh to the fifteenth and early sixteenth centuries. A further paper might well seem superfluous. My reason for offering one is that most previous writers have concentrated on analysing the professional circles from which the bishops were drawn, and suggesting the influences which their early careers as royal clerks, university masters and students, secular or regular clergy, may have had on their later work as bishops. They have shown comparatively little interest in their social background and provenance, except for those bishops who belonged to magnate families. Some years ago, when working on the political activities of Edward II's bishops, it seemed to me that social origins, family connexions and provenance might in a number of cases have had at least as much influence on a bishop's attitude to politics as his early career. I there fore collected information about the origins and provenance of these bishops. I now think that a rather more careful and complete study of this subject might throw further light not only on the political history of the reign, but on other problems connected with the character and work of the English episcopate. There is a general impression that in England in the later middle ages the bishops' ties with their dioceses were becoming less close, and that they were normally spending less time in diocesan work than their predecessors in the thirteenth century.

Sign in / Sign up

Export Citation Format

Share Document