The West Winford Incident (4 page)

Just before half past twelve a gradual change came about. Dave sensed this. The workmen's chatter subsided to a murmur; cigarettes were stubbed out, followed by a shuffling of feet away from the turbine. Then, as these men withdrew, they were joined by colleagues from other areas. Slowly a wide perimeter of the station staff, including office workers, canteen staff, and others, assembled around the cordoned off section. Taking his cue from Mike, Dave moved out to join them. After removing their hard hats, the assembled group settled.

A gap through the crowd had been left near the doorway to allow access for a small party of visitors. Several smart-suited men and a clergyman escorted a middle-aged lady with two teenage boys into the area vacated. The group moved to a prearranged spot. A few words were spoken; it was a sombre moment. Working men, heads bowed, haunted looks, rough men, reverent, some in tears. A few minutes' silence, apart from the background hum of the turbines. All thoughts focused on the man – Terry, exactly one week on. A moment of quiet, a moment of dignity. Dave, a stranger, felt the emotion.

As the visiting party withdrew and the men stirred and slowly returned to their duties, Dave was confronted by a wide-eyed worker, clearly angry and emotional.

“It's a bit late you, in your smart white suits, coming down here, aint it? Should do your job in the first place, not come here when it's time to pick up the pieces. Engineers? I've shit 'em.”

Dave was taken aback and made no reply as some of the man's colleagues helped him away with murmured apologies.

“Sad time for your first station visit,” said Mike, “so different from the usual noise and banter.”

Dave joined his engineering colleague for their return into Wiltshire. During the journey he reflected upon what he'd experienced on his visit. He was surprised at the devastated condition of Number 2 turbine. How could anyone hope to find the cause? At Fisher's Tubes he had come across failures of plant items involving their tubing, heat exchangers in particular, and had contributed to the investigation. However, a turbine was quite a different matter. Despite this, he had been hoping that, at some stage, he might be involved with the turbine failure enquiry and today's experience had reinforced that hope. His first duty though, was to continue to keep the day to day work progressing and he took some comfort from the fact that this was, in a small way, contributing to the West Winford effort in freeing up other staff members for the investigation.

Certainly, the demand did not ease and Dave continued to work long hours. Though difficult, he usually managed to get a couple of runs in during the week. His favourite route, when daylight allowed, was through the nearby Highwood Estate.

Gritty and Geoff undertook as much as they could fit in between their commitment to keeping the rigs running. Gritty was doing his best to look after the Fracture Group's work and the two secondments were surprisingly useful considering their lack of experience. The group did make time for occasional social evenings which, Dave felt, played an important part in engendering the team spirit between them. Despite all their efforts however, the backlog of work kept mounting.

Section members who were working on the turbine failure at Winford turned up at the labs occasionally to conduct tests as part of the investigation. Often they arrived, their car boots heavily laden with some large, distorted, metallic object which had originally been an integral part of Number 2 turbine. As Mike had explained the turbine layout to him, together with what he'd seen during his visit, Dave could appreciate much of what was arriving. He knew that the turbines operated at a running speed of 3,000 revs per minute and, once a month, each turbine was taken off the system for an overspeed test in order to check that the safety equipment, installed to control the speed of the turbine, was operating correctly. The test involved raising the speed of the turbine from its operating 3,000 rpm up to 3,300 rpm. The failure had occurred during an overspeed test on Number 2 turbine.

A detailed procedure had been established before items were removed from the Winford site. The first task was recording relevant details of the piece. An area was photographed untouched, then the larger fragments were removed, identified with a painted number or code, carefully replaced and re-photographed. It was not until an area had been recorded in this way that the pieces of debris could be taken away for individual examination. Work then moved on to another area of damage.

The next stage of the investigation was to examine the fragments to check whether any unusual defects were present. In most cases the piece could be confidently discounted as the primary cause. Others were less obvious and so the piece had to be put aside for more detailed inspection. An additional task was to attempt to identify where a particular fragment had come from and to try to rebuild some of the main components as a giant jigsaw. It was all very time consuming and the man-hours were building up. Dave understood perfectly, as he didn't know where his time went, there was just so much to do.

*

Time hung heavily for Sue, which she felt was ironic as she knew that she could not blame anybody but herself. She had been the instigator of the whole adventure. She reflected that as a young teenager she had been critical of the way many of the women she knew behaved. They were, for the most part, dedicated slaves and mothers. It annoyed her that their ambitions in life seemed to be limited to the traditional roles laid down by their mothers before them. She admired women that she'd read about who had not been prepared to settle for this mediocrity and had demonstrated that women could, and should, do more with their lives. She recalled the time immediately following her marriage when she had high hopes of moving away from the city and taking up a more meaningful career, whilst Dave found an equally fulfilling position. Her sister had married a nice steady boy in Pete, but he was so limited, so parochial. When she and Jenny were girls she had been the one who suggested joining the tennis club, belonging to a theatre group, spending the day at the Lickeys and so on. Her sister seemed to be happy to mooch around the house or hang about the local shops.

Just stop it. Stop it now Susan Turner! Words so familiar in the mouths of her schoolteachers, now seemed to be fully justified in the present case. Only she was going to alter the situation. She had always intended to get herself sorted out once they had settled. The fact that Dave was now so busy, so rarely at home, and when he was he was so tired, had brought things to a head more quickly. Tomorrow she would act.

*

Dave was finally awoken by the insistent phone. It was six thirty-five. It was Mike Pearson, clearly excited.

“Dave? Bit early I know, but can you get over here asap? We're in the rig hall. Got something that will interest you.”

“Er. Okay. I guess I'll be half an hour.”

“Come on, chop, chop. If you drive like Tony, you'll make it in ten minutes.”

Having shaken off the remnants of sleep, Dave was excited and intrigued. There were half a dozen already in the rig hall when he arrived. Mike, of course, with some of his Fracture Group colleagues, plus a couple of technicians, but most surprisingly, Tony Richards.

The group was gathered around a large piece of metal. Although not badly distorted, the item was clearly a fractured piece of the Number 2 turbine from West Winford, as it displayed its characteristic debris identification, LP/1AE, in bold white paint. Dave was invited to examine this. Mike pointed out a feature on the fracture surface of, what he explained was, part of the LP turbine disc they had seen on site. He reminded Dave that at its centre was a hole which allowed the disc to be slid onto the turbine rotor. Along the length of the hole was a groove (a keyway) which enabled a steel key to be fitted to locate the disc precisely into position. Whilst most of the disc surface was covered with a smooth, black oxidised layer, the fracture was clean, bright metal. Mike pointed to a small, though distinct, patch of discolouration near one edge of this clean surface.

“We think that's it,” he enthused, “the cause of the failure. What do you reckon, Dave?”

“I think that you can say that this discoloured area was present before the main fracture occurred. It comes from the keyway, so it's likely that this was cracked to that depth before the whole thing disintegrated.”

“Exactly,” agreed Mike. “If you remember, the main crack that we saw in this disc during our Winford visit started from the keyway. This section is just one side of that crack. The small piece that has been cut out is being prepared for the electron microscope. It contains part of the discoloured section. We called you in to take a butcher's for us. I should think the vacuum level is OK by now.” Mike led the way to the electron microscope room. John Bolton, the main man when it came to electron microscopy, was seated at the consol. The room was dark with just a small desk-light on to indicate the control positions. John acknowledged Dave with a nod and shifted to his left to allow Dave to wheel up a seat beside him. The eerie, greenish, display screen glowed, showing the sample taken from the LP turbine disc at low magnification. The variation between the discoloured and bright area of the fracture was obvious. However, both showed a ‘crystalline' surface even at this magnification.

“I'll bump it up a bit,” said John, turning up the magnification dial, and after refocusing, a clearer picture of the fracture surface emerged. The section visible at this higher level was from the brighter area of the surface and the crystalline nature of the fracture was obvious. This indicated that the fracture path had followed the grain (crystal) boundaries of the steel.

“Certainly brittle,” said Dave, “I suppose that that would be expected from such a thick section of steel. It's remarkably clean.”

“What about the discoloured area?” asked Mike, leaning forward over Dave's shoulder. John manipulated the specimen carriage until the discoloured area came into view.

“Ah!” breathed Dave. “Interesting. You can see the discolouration is typical of an oxide coating, mainly iron and chromium oxides, I expect. The other thing of interest is that this part of the surface is also crystalline and so whatever caused it also went for the grain boundaries.”

They returned to the main laboratory. Tony asked for Dave's opinion and the others waited eagerly. Dave pointed out that, based upon this preliminary examination, there were some useful indications. As he had not examined any of the other, goodness knows how many, hundreds of pieces of debris from the turbine, he had to accept the judgement of those who had, that this portion of LP turbine disc was the site of the actual fracture which probably caused the turbine failure. Given that proviso, it looked as though a crack, which had formed in the keyway area of the disc bore, had extended during turbine operation – the discoloured part of the fracture – until it had become deep enough to cause the rest of the disc to fail – the bright part of the fracture. It was likely that the failure of just one disc of this size at operating speed, would account for the extensive consequential damage noted, including the break-up of other discs. The surprising thing was that the depth of the initiating crack, that is the discoloured part of the surface examined, was so tiny; he guessed that it was not more than an eighth of an inch. He sat back to await comments.

“Wow!” exclaimed one of the technicians, “Are you saying that the bloody bomb site that we've spent the past couple of months picking through was all down to a sodding tiny crack of an eighth of an inch?”

Before Dave could answer, Tony asked the more pertinent question of how the initiating crack, small though it seemed, got there. Mike responded. He had spent many years looking at fractures and he thought that this one was likely to be due to some form of environmentally assisted cracking. It certainly was not caused by simple overloading, and metal fatigue, another possible candidate for cracking under these circumstances, was different, as the path of the crack would be through the grains rather than around the grain boundaries. He looked to Dave, hoping to receive confirmation. Dave supplied this.

“I agree with Mike. I would plump for stress corrosion myself. It may be significant that the failure occurred during a routine overspeed test, which is when the stresses on the disc would be greatest. Better get the views of others though.”

“Naturally,” replied Tony. “I shall be onto the Technical Committee chairman shortly, but I wanted us to have an opinion, albeit only a preliminary one. I better let Sweety know first, he'll be really chuffed. Good news at last.”

*

Having completed her essential chores, Sue just had to get out. A good walk would be the antidote for her mood. She set off and chose a route that would take her away from the lane and onto the Highwood Estate. The footpaths here were little used on weekdays, only the occasional jogger or dog walker. Just what Sue wanted, a couple of miles or so of quiet; time to think. She felt it ironic that she had been so anxious about how well the rest of the family would settle, but she had had no doubt about her own ability to cope. She had realised that the first couple of months would be taken up with getting the place just how she wanted, which she had more or less achieved. Her concern for Dave had proved unnecessary as, clearly, he was happy in the new job. Katy had also settled well. She had taken to rural life and made several friends. Even Jo seemed less of a problem than she had envisaged. Girls of her age were prone to be rebellious wherever they were and she didn't think that Jo was unusually unsettled. As for herself? Well, she was surprised.

The house was fine, as were most of the villagers, although some of the older residents did seem to require at least a forty year tenure before complete acceptance would be bestowed. Becoming involved in village activities as they came around, church fetes, summer fairs, and so on, would no doubt hasten their integration. This reminded Sue that she had volunteered herself and Dave to help at the school's Christmas bazaar/concert. However, these events were few and far between, so just what else did they all do? The village seemed to be stuck in a time-warp, activities and attitudes remaining unchanged since the nineteenth century. Sue needed something more challenging intellectually. The younger mothers seemed to fill their days with routine jobs interspersed with taking and fetching their offspring from the village infants' school. Maybe there were some women that she hadn't yet met who were in a similar position to herself. She could only hope. She realised that she was spending more time alone than was good for her.

She had to admit that it was wonderful countryside, some of the autumn colours determinedly hanging on. October had seen something of an Indian summer. Walks, such as these were fine, but it was the interaction with other people that she missed. She had been spoilt in that respect in Birmingham with her parents and her sister living locally. Being alone in the house all day was tiresome and this was made worse with Dave usually working late. She understood, he had to get on top of the job, but now this Winford thing had come along. What about her English Literature course work? She had been working through a correspondence course until a year ago. Perhaps she should look the stuff out.

She came to a fork in the path; if she kept to the left it would wind back to her starting point at the lower end of the village. The path to the right took the shorter route to the lane and through the village itself. As she was tired, having kept up a brisk pace, she decided to take this route. The first building at this end of the village was the pub. She wondered? As she felt warm, having been sheltered from the wind for the last mile, a drink would be welcome. Why not? Inside, the bar was quiet.

“Hello, Mrs Harrison,” greeted Sam, the landlord. “You're very welcome and luckily we've still the odd seat vacant,” he said, extravagantly waving his arms around the virtually empty room. “What's your pleasure?”

“Thank you. Just a half of shandy please.”

“Are you all settled in now?”

“Pretty well and everyone's been so kind.”

“Aye, they're not a bad lot, though they expect newcomers to conform to all their funny ways.”

“Yeah! You soon found that out when they vetoed your plans for a brothel upstairs.”

This wry comment came from a weather-beaten rustic perched upon a high stool at the far corner of the long bar.