Could a new owner of Liddell power station keep workers safe?

The current Australian Coalition government has been pushing for Alinta Energy, or another party, to take over the operation of the Liddell Power Station and run it well past its current proposed closure date in 2022.

As a reliability and maintenance engineer with power station experience, I know it is technically possible to run a coal fired power station well beyond their typical design life of 20 year.

But the risks are significant. Let’s look at some history.

Over 30 years ago in the Southern California Edison’s (SCE) Mohave Power Station in Laughlin, Nevada there was a massive steam pipe failure, unleashing high-pressure, superheated steam into the plant’s control room.

The explosion had such force that it knocked down a wall and sealed the exit doors shut. Sixteen people were severely burned in that explosion and six of them died. Some of the steam burns survivors had lost their hands, some had lost their legs and some parts of their faces.

The SCE company issued a report soon after that absolved itself of any wrongdoing but the investigation by the regional Public Utilities Commission found the opposite.

The company had failed to maintain the integrity and safety of the failed pipe and did not have an appropriate inspection program of their steam system piping.

This incident was a major influence on power stations around the world reminding engineers that high temperature steam pipes deteriorate over time through Creep Fatigue.

I know the NSW Electricity Commission, which  ran all NSW coal power stations at that time, initiated a substantial inspection program to assess and manage this risk.

That was a long time ago and there is little public information available that suggests all current coal fired power station owners in Australia maintain a similar safety programs for their high temperature steam pipes.

Last year I wrote an article to highlight the safety risk from high temperature steam pipe failures and the relatively recent horrific power station steam pipe failure in China that killed 21 people.

I highlighted the technical risk from this failure problem for Liddell power station, now around 45 years old. It was no surprise when someone in Australia’s reliability community sent me photos of an actual creep fatigue failure in a main steam main for Liddell Unit No.2. See photos 1 & 2 below.

 

 

Liddell Unit No.2 Steam Main Creep Fatigue Crack Failure Detail

 

Liddell Unit No.2 Steam Main Showing Creep Fatigue Crack Failure Location

(Just for Reliability techo’s – This is centreline crack in a major circumferential weld in a main steam line. The irregular nature of the crack and the rough texture of the surface of the crack is indicative of Type 1 creep cracking which is likely to have originated at an internal weld defect such as lack of fusion. Looks like some residual cracking at the toe weld just to the left of the first joint of the guys finger on Photo 1.

The main crack defect would require full weld removal and repair but there would be still issues with weld heat affected zone (Type II/Type III) since these cracks are more insidious {Comment from NDT, Plant Integrity & welding expert David Barnett}.)

Expert assessment of this crack indicated that a full failure of the steam pipe could easily have occurred with massive amounts of steam released and anyone near the released steam receiving horrific burns with major fatalities.

The severity of this crack would normally be interpreted as a strong indication that end of plant life has been reached. The Mohave Power Station pipe failure crack was not as bad as this one.

It is very easy for the non-engineering management of a company such as Alinta Energy to say that they can safely and reliably operate a very old coal fired power station.

I would advise any company taking over a 45-year-old coal fired power station with a less than stellar maintenance history to be wary of the hidden and not so hidden costs.

This is especially so with such a controversial plant takeover where there will be lots of public scrutiny of the safety and reliability performance of the plant.

Due diligence for any Liddell plant takeover would require a team with the engineering experience of the full range of safety, reliability and operational problems with very old power stations to develop the overall plant improvement program that would be required.

Alinta’s management should be wary of the very substantial funding that would be required.

The experience of the Labor’s home insulation scheme should make any politician wary of having their names too closely associated with controversial initiatives that may have future safety and fatality consequences.

Peter Todd is Chairman Asset Reliability Improvement Association