Friday, June 27, 2008
Anyway, following is some documention of my request and the response from our NRC. Click to enlarge.
Wednesday, June 25, 2008
The above slide is a burnout test with a totally blocked channel. The entire assembly is immersed in water (an open topped 55 gallon drum). The induction coil is insulated from the water.
This slide shows the capsule after the burnout. The capsule has swelled from internal pressure. The expanded capsule broke through the Vycor tube and an arc from the induction coil led to the pinhole leak. The 40 grams of NaK was totally reacted, but the reaction was not violent. This presentation will be expanded.
All of the nuclear power plants that installed UHI got rid of it, but it took a long time. The nuclear power suppliers, the consultants, and the utility managers got fat, while the workers suffered with the system and the ratepayers paid the bills.
As has been entered a few times in this blog, Leyse pinpointed the risks of UHI in his tragic (for him) memorandum UHI Ultra High Risk, October 3, 1994. Leyse believes that discussions between EPRI-NSAC and Duke staff led Duke to check out its McGuire installations of UHI. Duke then found four out of four level detection systems reverse connected. NSAC overlooked this in a meeting that reviewed PNO’s. Leyse was in that meeting, but upon seeing the Duke PNO he promptly left the meeting and began thinking about what to do next. Leyse wrote more memos. He was on the skids and that is another chapter to come later in more detail.
Of course, more followed and Duke got rid of its UHI systems. However, it was not until July 1987 that UHI was removed from McGuire-2 and November 1987 from McGuire-1. That meant that it took three years for effective action. During those three years, the ratepayers paid for loads of featherbedding activities prior to the removal of the Ultra High Risk. It may be argued that with the extra attention to UHI, the risk was less. Nevertheless, the large gas volumes were in place, armed to attack in the event of relatively minor system failures.
TVA stated up its Sequoyah Units 1 and 2 with UHI in service even though the risks of UHI had been disclosed and UHI was derided (deplored) by the ACRS. TVA finally removed UHI from Sequoyah-1 during March 1990 and from Sequoyah-2 during September 1990. “To prepare for removing the Sequoyah systems, TVA personnel practiced by removing the UHI system at the uncompleted Watts Bar-1,” quote from Nucleonics Week, January 14, 1991. Again, the featherbedders at the NRC, TVA and the reactor plant got fat while the ratepayers covered the expenses and lived with the ultra high risks.
I believe the first reactor to have been stuck with UHI was Kansai Electric Power. On January 14, 1991, Inside NRC reported, “Kansai Electric Power Co. is taking steps to remove its upper head injection (UHI) core spray system at its 1,120-MW Ohi-1 and Ohi-2 to correct plant inefficiencies similar to those at two U. S. utilities with similar reactors.” The reporter also disclosed that Kansai staff visited TVA during September 1990 to review TVA’s experience in removing UHI.
I don’t know when the Kansai’s Ohi units got rid of UHI, but if it was in 1991, that was seven years following my disclosures of October 1984.
Saturday, June 21, 2008
Here are a few pages selected from an extensive compilation of work by many.
The Vallecitos Boiling Water Reactor had a very high leak rate from this pipe crack that resulted from thermal stressing where cold feedwater was mixed with hot circulating water. It is very sad that the report is silent on the leak rate as well as the release of radioactivity to the environs (the VBWR was operating with leaking fuel). However, it is a valuable disclosure.
The last slide includes the fascinating discussion by Phil Bray of his TIGER code and the PHILCO 2000.
Click on each slide to enlarge and then hit y0ur back button to move on.
Thursday, June 19, 2008
Tuesday, June 17, 2008
Sunday, June 15, 2008
My Kingdom for a Comb!
Opal fuel modifications approved
01 May 2008
Approval has been given to use a modified fuel design in Australia's Opal research reactor, altered to prevent dislodgement of nuclear fuel plates.
Opal at full power. The blue glow isCerenkov radiation caused byfaster-than-light particles travellingthrough cooling water (Image: Ansto)The 20 MWt Open Pool Australian Light-water (Opal) reactor began commissioning in 2006, reaching full power during November that year. It is owned and operated by the Australian Nuclear Science and Technology Organisation (Ansto) and was supplied by Invap of Argentina.
On 24 July, however, it was noticed during refuelling that three of the reactor core's 16 nuclear fuel assemblies each had one of their 21 fuel plates partially dislodged. This appeared to have been caused by the motion of coolant water, which flows from the bottom to the top of the tank in which the core sits and causes a certain amount of vibration.
Ansto's response was to shut down the reactor in order to analyse the problem. The organisation decided that a revised fuel assembly design was needed because the existing fuel was subject to "inadequate design and fuel manufacture techniques." Ansto said the roll-swaging process used for the faulted fuel was to blame.
The new fuel plate design incorporates what Ansto describes as 'stoppers' which limit longitudinal movement within the fuel assemblies. These 'defence in depth' features, which Ansto said prevent significant movement, take the form of two 4 mm plates of aluminium fixed by two screws to a side-frame of the fuel assembly and are held in position by the screws and the assembly handling pin.
This design was approved today by the Australian Radiation Protection and Nuclear Safety Agency (Arpansa), and Ansto is now free to restart Opal when ready.
Ansto said in a submission to Arpansa that it would improve video surveillance of fuel assemblies with in-core video inspection before and after fuel changes. Ansto will also inspect fuel destined for Opal at the point of manufacture and perform pull tests on the plates in a test sample of each batch of new nuclear fuel.
Nuclear reactor design 'flawed from start'
By Dani Cooper for ABC Science Online
Posted Mon May 5, 2008 6:49pm AEST
Map: Lucas Heights 2234
A flaw in the original design of Australia's only nuclear reactor is partly responsible for the shutdown of the facility in July last year, just months after it was officially opened.
Dr Greg Storr, who heads reactor operations for the Australian Nuclear Science and Technology Organisation (ANSTO), says an "oversight" at the commissioning stage of the $400 million Open Pool Australian Lightwater (OPAL) reactor left it vulnerable.
His comments come as ANSTO staff begin reloading fuel into the reactor, based at Lucas Heights south of Sydney, following approval today from the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) to restart the reactor.
Dr Storr says he expects the reactor to be operating at full power by the end of the month.
OPAL replaced Australia's first reactor, the 40-year-old High Flux Australian Reactor.
It was meant to produce four times the amount of radio-isotopes for nuclear medicine than its predecessor and expand the nation's capacity for nuclear medicine research.
But the OPAL reactor was shut down three months after it opened when staff discovered during routine maintenance that some fuel plates had become dislodged and were projecting above, but still attached to the fuel assembly.
Worst case scenario
Dr Storr says in the worst case one of the fuel plates - which are about 2.5 millimetres thick, about eight millimetres wide and 800 millimetres long - was above the fuel assembly by about 400 millimetres.
Unlike similar reactors around the world, the OPAL reactor design did not have a secondary mechanism in place to stop the fuel plates moving.
"Not only did we miss it in our review, the designer missed it, ARPANSA missed it and internationally people [who were also tendering for the job] missed it," Dr Storr said.
But he says the movement of the fuel plates cannot just be blamed on the design fault.
ANSTO investigators have concluded the plate movement was caused by three factors.
These are the original design fault, vibrations caused by the rapid flow of cooling water up through the plates and a fault in the manufacturing process for the fuel plates used by Argentine company CNEA.
Dr Storr says in the OPAL reactor core there are 16 fuel assemblies that each hold 21 fuel plates made up of aluminium and small amounts of uranium.
The two outside fuel plates are screwed in while the 19 internal plates are slid into grooves and "swaged" or crimped in place.
Dr Storr says the tool used in Argentina to swage the fuel plates had been readjusted and was slightly out.
And tests at the manufacturing site had also shown the vertical strength in the swaging of the fuel plates was "less than expected", he said.
Dr Storr says these factors meant because the plate was not held in place as well as it should have been, once the swaging bond was broken the vibrations caused the plates to move upwards.
To fix the problem, which has been estimated to have cost about $100,000 a week in lost revenue, ANSTO is now sourcing its fuel plates from a French-based manufacturer.
The design of the fuel assembly has also been changed to include a stopper to prevent further fuel plate movement.
Dr Storr says the new design was tested by leaving all but seven fuel plates completely "unswaged" for 33 days, which is the equivalent of one full operating program.
At the end there was only very slight damage to two fuel plates, he says.
Under the return-to-service approval ARPANSA chief, Dr John Loy has required ANSTO to develop a program to more fully understand the vibrational and other forces acting on the fuel plates; review the design of the modified fuel assemblies within two years; and regularly test the longitudinal strength of the fuel plates.
Nuclear campaigner for Friends of the Earth, Dr Jim Green, says many critics of the Lucas Heights reactor would have preferred it was never turned back on.
Dr Green, who completed his doctorate on medical isotope supply options, says Australia has no need to manufacture its own medical isotopes as there is surplus supply worldwide.
He says research and development funds should instead be directed towards developing a cyclotron facility that can also produce the necessary isotopes without the safety risks and nuclear waste issues.
Note: OPAL fuel is 19.7% enriched, is U3Si2.
Saturday, June 14, 2008
As the world goes, one thing may lead to lots of stuff. I wrote a castigating review of this AEOD report on October 3, 1984. By early October 24, 1984, I had reasons to expand the distribution of my memo. And on November 12, 1984, the top man called for an investigation. The following three pages begin with his cover letter followed with my two page review that he marked up with his comments and highlighting. Here are the three pages. Again, click to enlarge.
Of course, I have been in this territory in prior entries. But it is a very involved set of things; I may have to write a book in order to cover it all somewhat more coherently. Would anyone read that?
Friday, June 13, 2008
HERE IT IS, CLICK TO ENLARGE
Here is the Incident Report of that wild time! It sounds less exciting than it was. An understatement from page 3 of this report, "2. It appears that the reactor scram aggravated the leak from the fuel element in the PWL."
I'll report more later. I have a copy of the pertinent parts of the log . Things were somewhat settled down by the graveyard shift on July 16, 1959. Paul Larson, the shift supervisor reported, "Carried a bottle of hydrogen to the third floor. Sure hope that elevator gets fixed today."
Science 20 September 2002:
Vol. 297. no. 5589,
pp. 1997 - 1999
NUCLEAR SAFETY:Nuclear Power Plants and Their Fuel as Terrorist Targets
Douglas M. Chapin, Karl P. Cohen, W. Kenneth Davis, Edwin E. Kintner, Leonard J. Koch, John W. Landis, Milton Levenson, I. Harry Mandil, Zack T. Pate, Theodore Rockwell, Alan Schriesheim, John W. Simpson, Alexander Squire, Chauncey Starr, Henry E. Stone, John J. Taylor, Neil E. Todreas, Bertram Wolfe, Edwin L. Zebroski
In the wake of the 11 September attack on the World Trade Center, a large number of outrageous public statements appeared, claiming that any attack on a nuclear plant or its fuel would be catastrophic. Because no effective rebuttal appeared from responsible agencies and organizations, a number of members of the National Academy of Engineering worked to hammer out a statement that all the signatories would be willing to publicly stand behind. This Statement, based on engineering principles and long, practical experience in nuclear technology, is presented as a Policy Forum.
Thursday, June 12, 2008
Click on each slide to enlarge.
Several decades later, Les Kornblith was cleaning out his files and he sent me this copy of our original submittal to the GE marketeers.