The West Winford Incident (11 page)

Sue seemed to take it all in her stride. Of course, the bilateral agreement with Betty Potter suited her. This arrangement, plus the car, had led to a great improvement in her quality of life and she was no longer dependent upon Pam, who had been away quite often lately anyway.

*

During idle moments Sue had wondered about Pam and her relationship with her husband. Although she had not met Lord Marden, she had seen his photograph in the local paper in a variety of roles, including cutting the ribbon across the front of a new block of flats and pink-clad on horseback at the local meet. He appeared to be older than Pam, but still an attractive, imposing figure. On occasions, Sue also contemplated Pam's precise relationship with Charles. Pam had, to Sue's knowledge, had several meetings with him, including at least one in her London flat. She wondered? Her thoughts then turned to Betty Potter and what her reasons for wanting to be away from home so regularly might be. A man?

Oh! Susan, do stop it. Inexplicably, Peter then came into her mind. What would people be thinking about her? Had anyone from the village seen them out together, say in the Crystal Palace in Bath? What would they be saying? She shook her head dismissively. It was nonsense. Peter was nice, charming and good company and that was it. She didn't care what other people made of it.

“Just how long are those bloody kids going to be here?” Sue was shaken out of her reverie by Dave's outburst. “They're becoming a blessed nuisance,” he continued.

“For goodness sake, Dave, they're kids, they're enjoying themselves. It seems you've forgotten what that was like since you've been down here.” Having said that, Sue went into the kitchen to prepare the evening meal. She was annoyed, partly with herself for her reaction to her husband's irritability. Her mood had been altered in just the few minutes that he'd been home. In recent times, there had been periods where an uncomfortable atmosphere simmered just below the surface between them and this was the case for the remainder of that evening. He was so completely focussed upon his investigations.

A couple of days later, Peter called to say that another London trip was planned shortly, did she want to take advantage of it? Sue responded enthusiastically saying that she would be delighted but she'd have to check with Mrs Potter. The arrangements were subsequently confirmed.

Dave called Ian into his office to learn how he was progressing with the extra set of specimens for the Winford rig. Ian reported that they were all loaded into the test frame and ready to go.

Tony Richards phoned to remind Dave that it was their turn to present an item for the departmental monthly seminar. He wanted him to make a presentation on the latest developments in the Winford investigation. He suggested that the main theme should be a general introduction to stress corrosion and its particular relevance in the case of the Winford LP disc cracking.

*

As Gritty was involved with an urgent job for the West Bay water treatment plant, Dave elected to go to Winford alone the following day. He was keen to get his on-site tests started. His first job on arrival was to climb the temporary scaffolding up to the Number 5 turbine LP steam inlet pipe, where the manifold valve arrangement had been fitted. He turned off the steam supply. When the vessel had cooled he removed the internal stainless steel trays and after loading his specimens, he replaced them in the vessel. At last, he thought, he could begin the test in earnest. As on the previous occasion, he only opened the steam valves partially to allow the specimens to warm up slowly. Later he turned the valves fully open, checked the temperature and pressure and was pleased to note in his pocket book:

TEST COMMENCED 1415 12
^th
March 1970.

Now that really did feel good. He had also been pleased to note that Bunsen's equipment was working; the various monitoring instruments clicking away, as the ink markers plotted their readings onto paper charts. At last he felt part of the investigation, such a major investigation too. He couldn't have imagined it a year ago – no, six months ago, even. He was in his element, doing real research of great practical value, not just an academic exercise.

His thoughts moved on to his family and his relationships with them. This part of his life was not going so well at present. The demands of this project had, he admitted, made him increasingly irritable, but Sue was being unreasonable as well. She was the one who had wanted the move and yet she had spent most of the time since complaining about her lot. He was working for the family, for goodness sake, and on the odd occasion when he socialised with his workmates at skittles, or whatever, she seemed to think it was unreasonable. Well, his chance had come, he had to grasp it, and he would. It may be that Sue's brother-in-law was under the thumb – but no, not for him.

*

The conference room was crowded. He hadn't thought that this topic would have been so popular. He supposed it could be that people wanted an excuse for a break from their own work, though he assumed that at least some had come along out of genuine curiosity. Although some of the staff, particularly the engineers and chemists, would have heard of stress corrosion, it could be that they had only a vague notion of the process.

The background chatter died down as Sweety rose to open the seminar. He reminded his audience that these meetings were held for good reasons, other than just getting away from desks and labs for forty five minutes' rest on a Friday – laughter. One reason, he continued, was to bring a project up for discussion when the research officer responsible felt that his work was in need of some fresh impetus, or where the future direction of the research was in some doubt. It had been found that comments from colleagues, from quite different backgrounds, had often given a new perspective, from which the project had later benefited. Today however, this was not the case, he told the audience. David Harrison of the Corrosion Group and his colleagues appeared to be progressing well with their investigations into the cause of the LP turbine disc failure at West Winford power station. He for one was looking forward to learning a little more about the process of stress corrosion cracking, which seemed to be the agreed mechanism responsible for the well-publicised incident. So, over to you David.

Dave began by saying that, as it was a cosmopolitan audience, he wanted to keep things simple. He hoped that those who were familiar with the subject would excuse him if he over compensated as he generalised. He went on to suggest that when the word corrosion was mentioned, most people thought of old cars, corrugated iron structures, seaside piers and so on. In other words things made of iron or steel, exposed to rain or seawater. “Surprisingly, in many cases, these do not present a serious technical problem. Certainly, the discolouration of the surface and an alarming amount of corrosion product – rust – appears to suggest a major loss of metal, but often this is superficial. This does, however, provide early warning, allowing timely action to be taken to avoid failure.”

He continued by asking his audience to consider a different situation where there is a sudden leak of a hazardous substance from a pipe, with no warning and no obvious evidence that corrosion has been taking place. No rusting, no unsightly brown surface deposit – nothing – just bright shiny, metal. This may be a vital part of some equipment, such as a transcontinental gas pipeline which has cracked completely through.

“The process of stress corrosion cracking, although less common than general corrosion, takes this insidious form of attack and is therefore potentially a much greater threat than the usual forms of corrosion, with which people are familiar.” He continued, “Stress corrosion is caused by the combined action of stress and corrosion resulting in the development of fine, usually deeply penetrating, cracks. This is not a new phenomenon, one of the earliest recorded instances being the cracking of brass cartridge cases at the time of the Indian Mutiny in the late 1850s. At the turn of the century, another series of stress corrosion failures occurred in steel steam boilers, due to the presence of sodium hydroxide in the boiler water.” He went on to say that some of the audience might be wondering why stress corrosion is not more common. The reason is that only a few chemical solutions cause this highly localised attack in just a few alloys. These solutions need to be sufficiently aggressive to cause some corrosion, but not so aggressive as to cause the attack to spread out as happens in the case of iron or steel in damp conditions, which he had mentioned earlier.

“Stress corrosion cracking often occurs in normally corrosion resistant alloys, such as brass or stainless steel, which possess good protective surface oxide films. If this film is damaged and corrosion results, the oxide film usually reforms quickly and prevents the attack from spreading laterally though, in the presence of a stress, it may continue to penetrate into the metal. Common solution/alloy combinations causing stress corrosion cracking include ammonia with brass, chloride solutions with stainless steel and sodium hydroxide with ordinary steel.”

Dave suggested to his audience that they would be relieved to know that he was nearing the matter in hand, at last; the Winford turbine disc failure. The discs were made from a medium strength, low alloy steel and from what he had already said, they could probably guess that the most likely cause of the stress corrosion cracking was sodium hydroxide. The boiler water at Winford, he reminded them, did contain some sodium hydroxide which, ironically, was added to prevent corrosion within the boiler itself. It was thought that at Winford some sodium hydroxide had been inadvertently carried over in the steam and entered the turbine, perhaps during some unusual boiler operation. This contaminated steam would have passed through the HP turbine as normal, as the steam would have been hot and dry at this stage. However, as it cooled and entered the LP part of the turbine, some wetness would have been present and droplets of contaminated moisture could have been deposited in the disc keyways and crevices. Although the concentration would have been very low, this could have gradually increased, as the steam in this area cycled between wet and dry depending upon turbine conditions. As the centre of the discs, that is the bore and especially the keyway, was under stress, all the conditions for cracking were present. Dave concluded by briefly mentioning his Winford test programme.

*

Peter's car drew up outside but before he had turned off the engine, Sue was half way down the front pathway. In just a short time she had become a practised genealogist, at least as far as the addictive behaviour was concerned. She joined her fellow enthusiasts. The morning was overcast and there were a couple of light showers during their journey, but it began to brighten as they neared London. Having parked at Hammersmith, the previous routine was followed with Sue and Kathleen retracing their steps to Somerset House.

Soon Sue was settling into her morning's exercise with the heavy index books – lift – turn – across – thump – search – return. She picked up the rhythm quickly. This time she was in the marriages section, searching for the marriage of three of her great, grandparents, firstly the Boughtons. She worked her way methodically through the quarters knowing that their son, Harry, had been born in 1878, so she needed to start at that year and work backwards through earlier years systematically. The search was on. The area in which she was working was crowded and this slowed her progress.

It turned out to be a long search, which entailed checking through twenty odd volumes, to find the entry she wanted; Thomas Boughton's marriage to Martha, which she found indexed in the April volume of 1872. The next marriage – that of James Loomes to Caroline Potten – took almost as long and so she had to abandon her search for the third marriage, through lack of time. She still had to fill in the request forms and pay her fees. She felt tired, hot and grubby after the hours of searching. So much for glamour, she thought, checking herself in the mirror in the Ladies, before meeting up with her travelling companions.

The four of them regrouped at Hammersmith and settled for the drive home. As they drove along the A4 past the White Horse at Cherhill, Peter said that he would prefer to take a different route from the morning one, which meant dropping off Kathleen and Maureen first and leaving Sue until last. He was, he explained, due to put in an extra session with his indexing team at St. John's in Bremham, which was more convenient for him. Having dropped the others, he stopped at Sue's and accepted her invitation for tea. They had just settled when Jo and Katy burst in with the customary sound track at full volume. This was reduced considerably when they found an unknown man sitting on the sofa. Strangely shy, considering that it was their home, they acknowledged their mother's introductions, though they kept their eyes on her the whole time. Quite soon and with the minimum of fuss, they were closeted in their rooms.

“Well, Peter that's one advantage of inviting you in that I hadn't anticipated,” smiled Sue. “A significant noise reduction, plus an early start on their homework. Perhaps you could call in every evening?” Sue placed Peter's tea, together with a selection of biscuits, on a small table beside the sofa.

Shortly afterwards, Katy peered around the door chewing the end of her pencil. “Mum,” she said, glancing shyly in Peter's direction, “can you come here a minute?” She was half in and half out of the room. Sue smiled and asked her to come in as Peter was unlikely to bite her. Katy did as she was asked and moved slowly into the room, passing quickly by the sofa containing the funny man, as she went to her mother's side.

“Do you know what – er” glancing at her homework book, “a palindrome is?” She seemed surprised when her mother said that she did.

“Why, what do you want to know?”

Katy leaned rather babyishly against her mother's knee and replied that they had to find as many as they could for school. As a special incentive, Mr Evans had said that there would be a prize for the child with the most.

“And have you got any yet?” asked Sue, trying to get Katy to stand away from her so that she could read what was on the page of her exercise book. “Yes, you've got deed and pop, bob, and level. That's a good start. Now try and think of some more.”

“Ooh! Mum, help me with some,” weaselled Katy.

“Erm, well there's madam and rotor and civic,” suggested Sue.

“How do you spell civic?” asked Katy, making a note of her mother's contributions. Sue spelt the word for her and added that it was really her homework and it wouldn't be fair on the others if she did it for her.

“Oh! Just one more then, please Mum.”

“Why don't you ask Peter? I bet he will know a good one,” replied her mother, looking across to him. Peter was touched, watching the charming family scene, of which he had no experience. He had a couple of nephews but rarely saw them.

“You ask,” said Katy from behind her book.

“Certainly not, it's your homework.”

Peter spared Katy further embarrassment by asking her if there were any extra prizes for the longest palindrome. Katy, still leaning against her mother, looked sideways and with a shy smile, shook her head.

“Well, in that case you won't want mine.”

“Oh, anything would do,” she coaxed.

Peter said that he would need her pencil and paper, so Katy decided that this was worth following up and she moved across to him. Peter wrote on the loose piece of paper that Katy gave him, as she climbed upon the sofa to see what he was writing. He pulled away from her to prevent her seeing. Sue watched with amused interest. Katy took the paper when Peter offered it and, with a puzzled frown, went back to her mother.

“What's this, Mummy?” she asked, showing Sue what Peter had written.

“That's a super one, isn't it?”

“But what is it?”

“Well you can read, so what does it say?”

“Was it a cat I saw? But what does it mean?”

“Well, it isn't just a single word, it's a sentence, but if you write all the letters backwards they will be in the same order as forwards, so it's a palindrome just the same.”

“Goody, Goody,” giggled Katy bouncing up and down before going gleefully upstairs. As if by magic, Jo appeared just as Sue was going into the kitchen and, without so much as a glance at Peter, she followed her mother. Jo, it appeared, also needed help as she had to write about Fox-Talbot at Laycock Abbey – her class was due to visit there soon. Sue wasn't sure of the details, she just knew that it had something to do with photography.