Thursday, 27 August 2009

Modern nuclear plant construction techniques

Some numbers are presented in the post below regarding nuclear power's expansion in Asia over the past 25 years. Achieving such consistent and sustained project implementation improvement is the result of considerable effort, innovation and investment.

Peruse the IAEA's website and you will find the results of a June 2009 meeting on Construction Technologies for New Nuclear Power Projects. Participants include Toshiba, Korean Hydro, Westinghouse, AECL, Sargent and Lundy, TEPCO, Murray and Roberts, and PMBR. Scroll down the page and you will find links to a number of informative presentations made during this event. Just a few details are included below.

Slip Forming
Slip forming is Reported to cut the concrete construction phase of a reactor building from 6-9 months down to 13 to 20 days. In this innovative technique, concrete is poured continuously between two climbing wall faces. Multiple platform levels allow for preparatory work, concrete pouring and curing to take place as the form 'slips' upward at a rate from 2.5 to 15 cm per hour. In addition to being faster, the elimination of 'cold joints' makes the resulting structure safer (improved resistance to leakage).

Slip forming - start

Slip forming - near completion

Open Top Construction combined with modularisation
The Reactor Building is partially completed and left 'open'. Very heavy lift (VHL) cranes are then used to install large components from above. Mechanical and electrical systems are installed from and through building openings in parallel. Open top construction permits more activities to be progressed in parallel compared with construction techniques of the 1970's.

Modular construction reduces field work and, because the modules are fabricated in the controlled environment of a fabrication facility or a covered assembly area near the main site, quality is improved. The challenges include increased front-end engineering and planning effort, increased rigging and transport costs, and early material requirements.

Modular component - RB base slab rebar mat

Modular component - large bore piping module

Modular component - Integrated plant, large bore pipe and structure

Modular component - Upper drywell (BWR)

Modular component - Control room

Advances in system assembly and fabrication have also added the double advantage of reduced time and improved quality.

Automated large bore pipe joint welder

Advanced planning and detailed engineering
Modern nuclear plant construction techniques - in particular open top construction, slip forming and modularisation - require considerable planning. For example, detailed engineering must be complete long before construction initiation to support the fabrication and assembly of large modules like those shown above - to the timeline demanded by the project schedule. Modern procurement processes receive the final engineering design documents and develop detailed estimates, determine material and component lead times, and pre-qualify potential suppliers. Experienced planners and schedules develop installation plans that are often referred to as 'choreographies'; developed so well that costly support equipment, such as heavy lift cranes, practically never come to a rest.

However, design standardisation reduces the engineering burden considerably from First of a Kind (FOAK) out the the n-th construction project. For example, once a complex module has been engineered for a standard plant design, very little engineering effort is required to reproduce the same module for the 2nd, 3rd,... n-th plant to be constructed.

Laydown plan

In addition, activities are planned to run in parallel, non-stop, regardless of weather conditions.

All weather construction roof - removable roof staged to the side (4 sections in blue)

All weather construction roof - mounted in position

Continuous feedback and incorporation of lessons learned
Any competent company will incorporate the lessons of one project into the next. Another good practice is to draw from the experience from a cross-cutting of industries. As one might expect, experience is being drawn from all aspects of modern, large scale construction, such as experience from South Africa's Murray and Roberts.

Finally, the meeting included a presentation on the progress of the inaugural AP1000 project (China). The presentation includes examples of the techniques mentioned above.

Saturday, 22 August 2009

Nuclear data source - IAEA

Per it's statute, The International Atomic Energy Agency (IAEA) has a single objective:

The Agency shall seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world. It shall ensure, so far as it is able, that assistance provided by it or at its request or under its supervision or control is not used in such a way as to further any military purpose.

IAEA Headquarters - Vienna, Austria

A function or means to achieve this objective is the collection, collation and dissemination of relevant data. Items of interest include:

The PRIS database - Containing recent plant construction project initiations, plant startups, shutdowns as well as lists of facilities by country and World Summary information such as nuclear power's percent share of total electricity generation, etc.

The Fast Reactor Database - as one would expect, but also including recent and upcoming meetings.

The Integrated Nuclear Fuel Cycle Information System - information relating to fuel cycle activities (mining, milling, conversion, enrichment, fuel fabrication, etc.) throughout the world.

Planning and Economic Studies (webpage) - home to many statistics about nuclear power's role in sustainable energy policy planning.

And there are many more.

It's important to consider the data in an integrated context. In isolation, they can be easily misinterpreted - or worse, misrepresented. For example, the PESS site shows China at the very bottom of the % nuclear share of total electrical generation (1.9%). However, looking at the PRIS entry page alone will quickly reveal that China's current nuclear build program is unparallelled: five project starts already in 2009 and six in 2008. That's quite a leap from only two project starts in both 2007 and 2006, one in 2005 and none in 2004.

Thursday, 13 August 2009

25 GWe by 2050? Show me.

Is it even possible Australia could get itself organised and construct up to 25 nuclear power plants by 2050?

Let's make a liberal assumption and then look at some regional data compiled from the IAEA's PRIS database.

First, the assumption. Even those sceptical of nuclear power's role in Australia claim it will take 15 years to construct even one power plant. Alright then, let's better that and assume it takes us 15 years to even begin construction of the first plant. Therefore, we'll assume the first construction project begins on 01-January 2025. Can we average one plant a year for the remaining 25 years?

Now to the region.

Since 1984 (25 years ago). India has begun and finished 9 nuclear plant projects (over 2,300 MWe of net capacity). Over this time, construction project durations have been cut in half. The three most recent projects (all commencing operation after 2005) were brought in at just over 5 years.

Since 1984, China has begun and finished 11 nuclear plant projects (over 8,400 MWe of net capacity). There is not much difference over these 11 projects. The minimum construction time is 4.5 years, the maximum is 6.7.

Since 1984, Korea has begun and finished 11 nuclear plant projects (over 1o,ooo MWe of net capacity). Korea has had consistently short construction durations, but have still managed to improve over time. Only 2 of their 11 projects exceeded 5 years (5.1 and 5.2). The minimum time is 4.0 years.

Since 1984, Japan has begun and finished 21 nuclear plant projects (over 20,000 MWe of net capacity). The project performance in Japan is impressive. Only 2 of the 21 plants were connected to the grid 5 years or more following the beginning of construction (maximum time is 5.2 years). 14 of the plants were connected in less than 4 years and the minimum construction time was just 3.2 years.

And those were not times of energy / environmental crisis.

25 GWe nuclear capacity in Australia by 2050 is certainly within the realm of possibility.

Japan and Korea: Improving construction project durations
(Source: IAEA PRIS Database)