View/Open - Naval Postgraduate School

nuclear plant construction (Lake, 2002; Kharbanda & Pinto, 1996; Feldman et al., 1988;
Lillington, 2004; Friedrich et al., 1987). Examining construction records from the Nuclear
Regulatory Commission from this period provide two examples of possible tipping point dynamic
failure.
The first example of a project that crossed this tipping point is the Tennessee Valley
Authority’s (TVA) Watts Bar nuclear power plant units 1 and 2. TVA began the construction of
the Watts Bar facility in December of 1972 (NRC, 1982). Originally the facility was to consist of
two 1165 MW units that were to both be on-line by the middle of 1977 (NRC, 1982). However,
as Figure 1 shows, the two units were unable to meet the planned deadline. By mid 1977, Unit 1
was 57% complete and Unit 2 was 49% complete. In May of 1974, the TVA reported delays due
to the redesign of the reactor containment vessel to accommodate higher pressures, an inability
to obtain redesigned anchor bolts and reinforcing rods, and increased time to erect steel plates
that were thicker than the original specifications (NRC, 1982). The work created by the
problems beyond the original scope (e.g., additional anchor bolts or steel plates) are evidence
of adding new tasks. Work was halted in 1980 for five years to address worker safety concerns
with the design of the plant (Lee, 1995). To address these concerns, the TVA spent nearly one
million man hours reviewing the design of the plant (Lee, 1995). This review lead to the
replacement of nearly three million feet of cable, 8,000 pipe supports, and 25,000 conduit
supports (Lee, 1995). The TVA canceled Unit 2 in 1995 with the unit 61% complete (Nuclear
Engineering International, 1995). The TVA estimated that it would cost more than the $1.7
billion already invested in Unit 2 to complete the unit. When Unit 1 finally came on line in 1996,
the TVA had invested nearly $7 billion dollars in the facility (Lillington, 2004). The decrease or
stagnation in the fraction of the total project scope that has been completed (right side of Figure
1) is a characteristic behavior of projects experiencing strong ripple effects.
% Complete
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Watts Bar 1
Watts Bar 2
Jul-72 Dec-73 Apr-75 Aug-76 Jan-78 May-79 Oct-80 Feb-82 Jul-83
Figure 1. Watts Bar Construction Progression (1973-1982) (NRC, 1982)
=
=
==================^Åèìáëáíáçå=oÉëÉ~êÅÜW=ÅêÉ~íáåÖ=ëóåÉêÖó=Ñçê=áåÑçêãÉÇ=ÅÜ~åÖÉ=======- 341 -
=
=