[ RadSafe ] query - Fort St. Vrain

[Bernard L. Cohen]

Many thanks for all the info. I had not realized that it had operated so 
long and produced so much electricity.

Sandy Perle wrote:
>
> Everything you ever wanted to know about Fort St. Vrain:
>
>  
>
> Built in the shadow of the majestic Rocky Mountains, Fort St. Vrain 
> (FSV) was Colorado's only Nuclear Power Plant and America's only 
> commercial High Temperature Gas Cooled reactor design.  Plans to 
> construct FSV were announced in 1965.  Work began at the site in 
> 1968.  Initial hot flow testing of the reactor began in 1972, and 
> several years of design problem work followed.  The first commercial 
> electric power using the reactor was generated from the plant in 
> December 1976.  Nuclear operations came to a close in 1989 due to 
> continuing problems with the plant.  Decommissioning of the reactor, 
> as well as shipping of all nuclear fuel off-site to a U.S. Department 
> of Energy managed facility, was complete in 1992.  Fort St. Vrain was 
> the first commercial nuclear generating plant in the United States to 
> be decommissioned.  In 1996, generation from FSV began again, this 
> time with a combustion turbine burning natural gas and generating 130 
> megawatts of power.  A heat recovery steam generator (HRSG) was added, 
> and steam was provided to the old main steam turbine.  A second gas 
> turbine with HRSG was added in 1998, making  FSV capable of 500 
> megawatts.  In May 2001, a third combustion turbine with HRSG was 
> added, making the final rated output of the plant 720 megawatts. 
>
>  
>
> *The Rest of the Story*
>
>  
>
> Public Service Company of Colorado (PSC) was researching alternative 
> power generation as early as the late 1950s.  Plans to build Fort St. 
> Vrain were announced on March 13, 1965 and the application to 
> construct FSV was filed with the Atomic Energy Commission 
> <http://www.nrc.gov/> on October 20, 1966.  It would be the first 
> commercial scal high temperature gas cooled reactor plant in the 
> United States.  The plant was to be named after the historic frontier 
> fort <http://stvrainsfort.homestead.com> of the same name, once 
> located about a mile north of the power plant site. 
>
>  
>
> Preliminary construction work on FSV began in April 1968 after 
> receiving approval from the Colorado Public Utilities Commission 
> <http://www.dora.state.co.us/puc/>.  The U.S. Atomic Energy Commission 
> issued it's construction permit on Sept. 18, 1968 and concrete work on 
> the reactor building began.  Gulf General Atomic <http://www.gat.com/> 
> (GA) was the prime contractor.  Sargent & Lundy 
> <http://www.slchicago.com/home/> subcontracted to GA for architectural 
> and engineering and Ebasco was the principal constructor.
>
>  
>
> To meet the earthquake design criteria the reactor building was 
> engineered to rest on bedrock.  This proved to be a problem right away 
> because bedrock was 50 feet down through sandy soil and a water table 
> at 20 feet.  This major obstacle was overcome by freezing the ground 
> around the area to be excavated.  A total of 360 fifty-five foot long 
> U-tube assemblies, all connected together, were installed in the 
> ground in an oval shape around what would become the reactor 
> building.  A freezing brine solution was pumped through these pipes.  
> Three huge refrigeration systems maintained the brine at minus 11 
> degrees Fahrenheit.  The "freeze wall," as it was known, was started 
> on May 6th, and by June 3, 1968, the majority of the wall was frozen.  
> The foundation was actually dug down 25 feet below the normal surface 
> of the bedrock.  Once they reached the shale bedrock during 
> excavation, it was found that it deteriorated rapidly upon exposure to 
> air.  Final excavation and concrete pours were carefully coordinated 
> to minimize the deterioration. 
>
>  
>
> Also in June 1968 construction of the reactor bottom head assembly was 
> begun west of the reactor building while the building foundation and 
> support ring for the pre-stressed concrete reactor vessel  (PCRV) were 
> being constructed.  This assembly consisted of the steel liner, 
> penetrations, and core support floor columns and weighed in at 400 
> tons.  In February 1969 it was moved on rails to temporary supports 
> within the support ring.  The support ring was completed on Feb 13, 
> 1969.  It is a cylinder, 50 feet in diameter with highly reinforced 
> walls 3-1/2 foot thick and 33 feet high.  It required 575 cubic yards 
> of concrete and was completed in one 18 hour continuous pour.
>
>  
>
> A different approach was used in the construction of the turbine 
> building foundation.  Sixty-six caissons were drilled into the bedrock 
> and casing were installed.  Once the casings were in place they were 
> pumped dry and the bedrock was drilled out an additional 6 feet.  The 
> done, reinforcing steel was lowered into the casing and then the 
> concrete was poured.
>
>  
>
> Turbine building structural steel was 70% complete by Oct. 1, 1969.  
> Turbine generator erection was started at this time.
>
>  
>
> Hot Flow testing was begun in June 1972.  The pelton wheels 
> disintegrated due to cavitation.  A pelton cavity nitrogen 
> pressurization system was designed and implemented by May 1973.
>
>  
>
> Fuel loading to the reactor began on December 27, 1973, after the 
> operating license was issued.  Fuel loading was completed on January 
> 16, 1974, and initial criticality was reached on January 31, 1974.  
> The rest of the year and into the early spring of '75 was spent 
> working on problems with the contol rod drives, moisture ingress into 
> the reactor, and pelton wheel cracks.
>
>  
>
> Rise-To-Power testing to 2% occured in April 1975.  However, as a 
> result of the Browns Ferry fire 
> <http://www.ccnr.org/browns_ferry.html>, an internal PSC cable 
> segregation audit was conducted.  In June, the Nuclear Regulatory 
> Commission <http://www.nrc.gov/> (NRC) ordered a full audit of all 
> essential and associated non-essential cables with respect to 
> compliance with the Final Safety Analysis Report.  The reactor 
> remained shut down during all these audits.  Another problem, internal 
> leakage in 15 of the control rod drive assemblies, required the rest 
> of '75 and early '76 to resolve.
>
>  
>
> On July 6, 1976, FSV reached power levels greater than 2%.  However, 
> the "C" helium circulator had to be replaced due to excessive purified 
> helium leakage from the penetration interspace into the pre-stressed 
> concrete reactor vessel (PCRV).  October to November saw rise-to-power 
> testing and minor modifications to the startup bypass pressure control 
> system and steam/water dump relay system.
>
>  
>
> *_First Power Generation_*
>
>  
>
> On December 11, 1976, FSV generated its first electrical power to the 
> grid using reactor power.
>
>  
>
> Core thermal fluctuations were observed on November 23, 1977.  Reactor 
> power was reduced to 68% power.  Then a small steam generator tube 
> leak was detected on November 30th, and the reactor was manually shut 
> down so repairs could be made.
>
>  
>
> The turbine was again placed on line on April 3, 1978, and testing was 
> begun to determine the nature of the thermal fluctuations observed 
> earlier.  The NRC had imposed a 70% reactor power limit (which was 
> below the threshold of the thermal fluctuations).
>
>  
>
> The reactor was shut down for first refueling on February 8, 1979.  
> Refueling was completed on May 2nd and the reactor was taken critical 
> on May 26th.  In June, PSC signed an agreement to assume ownership of 
> the plant from General Atomics (GA).  The reactor was operated at less 
> than 2% power for testing until July, when the turbine was once again 
> put on line to generate electrical power.  Commercial operation of the 
> plant officially began on August 1, 1979.
>
>  
>
> In October, the reactor was shut down for the installation of region 
> constraint devices, better known as "Lucy Locks."   The lucy locks 
> were installed to address the core fluctuations.  Research by GA and 
> PSC engineering had come to the conclusion that the blocks were 
> shifting around slightly under power.  They reasoned that the Lucy 
> locks would hold the the block columns together and prevent the 
> fluctuations.  Lucy locks in place, the reactor was taken critical on 
> December 25th.  Our fluctuation problems were cured.  However a 
> problem was found on the "B" helium circulator primary seal, and the 
> reactor was soon shut down again.
>
>  
>
> The "B" helium circulator was replaced (a huge job), and the turbine 
> was back on line on March 16, 1980.  In August, the plant was shut 
> down for required surveillances (testing) and planned maintenance but 
> was back on line, generating power on October 8th.
>
>  
>
> Excessive interspace leakage on the Loop 2 steam generator 
> penetrations required a shutdown on March 22, 1981, but FSV was back 
> on line with the generator on April 13.  However, turbine high 
> vibration caused a turbine trip, resulting in a reactor scram on May 
> 13th. 
>
>  
>
> Rather than start back up, the second refueling outage was begun a 
> little ahead of schedule.  Refueling was completed, the reactor taken 
> critical, and the generator was back on line on July 26, 1981.  On 
> November 6th, the reactor reached 100% power.  This was great day!  
> However, the reactor was shut down on November 9th to begin the "loop 
> split" outage in order to create two independent paths for buffer 
> helium for better reliability.
>
>  
>
> The loop split modifications were completed and the reactor taken 
> critical on February 11, 1982.  On Feb. 22nd, the reactor was manually 
> scrammed due to high moisture, and two control rods failed to properly 
> insert.  Three additional rods exhibited a tendency to stick in the 
> full-out position.  A program was initiated to exercise the control 
> rods and all were operating properly by February 23rd.  The reactor 
> was taken critical on April 2nd and the generator put on line on April 
> 4 but the plant was shut down again on April 20th to repair a core 
> supposrt floor tube leak and test the reserve shutdown system.  On May 
> 3rd the reactor was taken critical again and the generator was placed 
> on line on May 7th.  FSV scrammed again on September 30th.  In October 
> the NRC granted release from the 70% power limitation imposed during 
> the thermal fluctuations.  The reactor was taken critical for training 
> during the first week of November but high primary coolant moisture 
> problems kept FSV at low power or shutdown.
>
>  
>
> The turbine generator was placed on line on January 1, 1983 but high 
> primary coolant moisture scrammed the reactor again on January 28th.  
> The generator was back on line again on February 8th but the reactor 
> was manually scrammed on February 14th after the loss of  the "B" 
> instrument power inverter.  The reactor was kept shut down while a 
> possible core support floor leak was investigated.  The generator was 
> back on line on March 9th and scrammed again on high moisture on March 
> 17th.  The reactor was brought on line again on May 24th, but power 
> was limited due to high moisture.  The moisture gradually decreased, 
> and the generator was finally placed on line on July 16th.  Things ran 
> pretty well for a while. 
>
>  
>
> Next, FSV experienced high vibration problems with "C" boiler feed 
> pump.  Reactor power was taken to 80%.  Vibration problems continued 
> with the boiler feed pump.  Consultants were called in and various 
> avenues were tried to solve the problem to no avail. By October 
> reactor power was up to 85%.  However, on November 9th, the boiler 
> feed pump seized up and tripped.  If that wasn't enough, on December 
> 8th the reserve auxiliary transformer deluge system was activated by 
> high winds resulting in a turbine trip and reactor scram.  The reactor 
> was immediately taken critical and the steamer was back in service on 
> December 11th.
>
>  
>
> On January 20, 1984, the reactor was shut down for refueling, a 
> turbine overhaul and electrical modifications.  In February the 
> Colorado State Public Untility Commission recommended a $526,000.00 
> rebate to the Public Service customers, due to the poor performance of 
> the plant. 
>
>  
>
> In March an inspection of the PCRV tendons revealed failed strands in 
> the tendon bundles. 
>
>  
>
> In April, while FSV was awaiting release to go to power from 2%, 
> problems arose with sticking orifices in regions 12 and 30.  The 
> region 12 control rod drive assembly had to be replaced, but region 30 
> freed up after excercise.  Permission to go above 2% power was 
> received from the NRC on May 16th, after their evaluation of the PCRV 
> tendon wire degradation.  The process of drying out and gradual 
> reactor power increase continued until June 12 when the generator was 
> placed on line.  However, due to moisture, reactor power could only 
> slowly be increased.  Then on June 22nd a sudden pressure relay on the 
> 4160/480V transformer #1 caused a trip of the 480VAC essential bus 1A 
> and subsequently tripped the "A" helium circulator, due to a bearing 
> water upset.  Trying to recover from this incident, we scrammed on 
> high reactor pressure on June 23.  During this event, six of the 
> thirty-seven control rod paris failed to automatically insert.  A 
> powered insertion to the stuck rods was successful.  Cold shutdown 
> conditions were achieved by the initial scram, however.  This scram 
> signaled the beginning of an extensive control rod drive refurbishment 
> program.
>
>  
>
> During a test of the reserve shutdown system in Novemeber 1984 for 
> control rod drive #21, the boron balls failed to discharge properly 
> from their hopper.  A event report was filed with the NRC. In 
> December, helium circulator A was removed and shipped to San Diego for 
> repairs on an interspace bearing water leak.
>
>  
>
> By February 1985, control rod drive refurbishment was in full swing.  
> The helium circulator was returned from San Diego in March.  During 
> the repair work at San Diego, GA Technologies discovered chloride 
> stress corrosion on some of the internal bolting.  Therefore, the rest 
> of the circulators would have to be removed and inspected.  One by 
> one, the circulators were removed, repaired and reinstalled.  The 
> on-going control rod drive work was completed in June 1985, at about 
> the same time as the circulator repair work.
>
>  
>
> Permission to start up the reactor (at loads up to 15% until 
> Environmetal Qualification issues were resolved) was rececived on July 
> 19 and the reactor was taken critical the next day.  A high moisture 
> scram occured on July 23rd, and the reactor remained shutdown for a 
> time for primary coolant cleanup.  A new digital valve that had been 
> installed on on "A" circulator experienced leakage and was replaced 
> with the original valve.
>
>  
>
> The reactor was taken critical a few times during the summer of 1985 
> to try to dry out the primary coolant but the turbine was never placed 
> on line.  In November the reactor was shutdown for mandated 
> Environmental Qualification modifications.
>
>  
>
> In January 1986, while returning a clearance on "D" helium circulator, 
> a water ingress into the PCRV of approximately 300 gallons occured.  
> The reactor was taken critical on February 14th and power was slowly 
> increased during March, while primary coolant cleanup continued.  On 
> April 3, a major snow storm caused voltage upsets on the grid, 
> resulting in an automatic shutdown of Loop 2 and the isolation of "B" 
> purification train.  Management directed a manual scram.  The reactor 
> was up again on April 6th, and the turbine on line on April 11th.  On 
> April 27, an automatic reactor scram was generated accidently due to a 
> routine surveillance test on the plant protective system (PPS).  The 
> generator was placed back on line on April 29.
>
>  
>
> On May 6th, an electrical grid transient occured which increased 
> reactor power to a maximum of 39.2% (FSV was limited to 35% power at 
> the time by the NRC).  Leakage through a main steam bypass pressure 
> control valve upset the overall plant, but the problem was corrected 
> and operation returned to normal.  Steps were taken to prevent reactor 
> power from increasing above 30%.
>
>  
>
> *_"EQ"_*
>
>  
>
> On May 30th the turbine was taken off line, and on May 31st the 
> reactor shut down for government mandated Environmental Qualification 
> (EQ) modifications.  In June, clearances were hung on the circulating 
> water system, resulting in flooding the pump pit.  All affected motors 
> were removed for inspection and repair.  During the EQ outage, staff 
> at the plant swelled to an all time high of 965.  This number included 
> contractor and PSCo personnel.
>
>  
>
> Next, on July 7, 1986, the NRC imposed civil penalties on Fort St. 
> Vrain for the May 6 over power event ($75,000) and for inadequate 
> protection of protected and vital areas ($65,000). 
>
>  
>
> On September 24, 1986, Public Service reached an agreement to settle 
> all litigation concerning Fort St. Vrain.  The settlement removed FSV 
> from the company's rate base, provided customer refunds, and reduced 
> electric rates.  The plant was to be run essentially as an independant 
> power producer and could charge 4.8 cents per kWh.
>
>  
>
> In March 1987 FSV completed the Environmental Qualification program, 
> and on June 17th the NRC voted to allow FSV to return to power, not to 
> exceed 82%.  Unfortunately, on July 28th a purified helium leak was 
> found in the interspace of "D" circulator.  The reactor was shutdown 
> again and "D" circulator was removed and sent back to San Diego.  A 
> spare circulator was installed.  The reactor was again taken critical 
> on September 30.
>
>  
>
> On October 2 a hydraulic oil fire broke out in the area of a hydraulic 
> valve (HV-2292) in the turbine building.  A manual reactor scram was 
> inserted because of an indicated loss of primary and secondary coolant 
> flow.   The fire was extinguished by the plant fire brigade.  Repairs 
> were made.
>
>  
>
> The reactor was again taken critical on December 11th.  By January 16 
> 1987, FSV was at 77% reactor power, beginning the first sustained 
> period above 72% power since 1983.
>
>  
>
> FSV set a new record for total net generation during a single month of 
> 160,184 MWhe during March 1988.  In April more problems arose again 
> and the plant was up and down, due to circulating water problems and 
> electrical system upsets.  However, in June FSV set another new record 
> for generation.
>
>  
>
> *_End of Nuclear Operation Announced_*
>
>  
>
> However, in December 1988 the decision was made by the board of 
> directors of Public Service Company that Fort St. Vrain would be shut 
> down for good.  The NRC was notified that the plant would shutdown no 
> later than June 30, 1990.
>
>  
>
> In March 1989 the independent safe fuel storage installation (ISFSI) 
> request for proposal was sent out.  The preliminary decommissioning 
> plan was submitted in June.  In July a new generation record for a 
> one-month period was attained and Foster Wheeler <http://www.fwc.com/> 
> was selected as the ISFSI vendor.
>
>  
>
> The plant was returned to power service on April 9 following a reserve 
> shutdown problem.  FSV reached 80% reactor power on May 29.
>
>  
>
> The summer of '89 was a hot one and Public Service set an all time 
> record for power output.  For once, FSV was up and fully loaded!
>
>  
>
> On July 30th the plant recorded an all time monthly record power 
> production of 178,221 net megawatt-hours.  On August the 4th FSV 
> employees celebrated the outstanding recent performance of the plant 
> and the new record with a picnic on the front lawn.  There was 
> volleyball, horseshoes, a dunk tank (proceeds of payment to "dunk your 
> favorite boss" went to United Way) and enough food for 500 employees.
>
>  
>
> *_The End Came Early!_*
>
>  
>
> On August 18th during routine surveillance testing a control rod drive 
> assembly was found to malfunction.  The plant was shut down and 
> preparations for repair and return to service were begun.  However, 
> during a routine walkdown by one of the plant engineers, hairline 
> cracks were found in the inconel steel main steam ring header 
> immediately below the reactor.  This ring header received steam from 
> the steam generators in the reactor prior to the steam's short trip to 
> the turbine generator.  The hairlinge cracks proved to be */the/* last 
> straw for Fort St. Vrain.  Based on this turn of events, the PSC Board 
> of Directors announced the decision to terminate operations at Fort 
> St. Vrain effective on August 29, 1989.
>
>  
>
> From November 1989 through February 1990, fuel was removed from twelve 
> reactor regions and stored in the fuel storage wells located on the 
> fuel deck in the plant reactor building.
>
>  
>
> The Nuclear Regulatory Commission (NRC) issed the Confirmatory 
> Shutdown Order for FSV in May 1990.  In June, the Independent Spent 
> Fuel Storage Installation (ISFSI) license application, safety analysis 
> report, and environmental reports were submitted to the NRC.  The 
> ISFSI was needed because plans to ship Fort St. Vrain's spent fuel to 
> the Department of Energy facilities in Idaho under a 1965 contract 
> were halted by a lawsuit filed by the State of Idaho.  So, the ISFSI 
> was considered as a contingency.
>
>  
>
> In July the Westinghouse team was selected as the decommissioning 
> contractor. 
>
>  
>
> The decision to proceed with construction of the ISFSI was made in 
> January 1991, and construction began in February.  In May, a 
> "possession only" license was issued by the NRC.  The Final Safety 
> Analysis Report was submitted to the NRC in July 1991.
>
>  
>
> In October 1991, three shipments (eighteen fuel elements) of spent 
> fuel were sent to the Idaho National Engineering Lab 
> <http://www.inel.gov/>.  Also in October, all non-union employees were 
> required to bid on the remaining positions for "early dismantlement".  
> This was a very tramatic time that none of us will forget.  An 
> employee either got picked for a position or got a 90-day notice.  
> Simple.  On November 22nd the names of 38 non-barganing unit personnel 
> were announced.  The union employees went through a similar procedure 
> based on seniority.
>
>  
>
> The NRC issued the Materials License and Safety Analysis Report for 
> ISFSI in November 1991 and the first load of spent fuel was deposited 
> there on December 27th.  Fuel shipping was completed  into the ISFSI 
> on June 10, 1992 and the nuclear security and nuclear fitness for duty 
> programs were terminated shortly thereafter.  Fort St. Vrain received 
> the Public Service Company Eagle Award as recognition for completing 
> defueling "months ahead of schedule--saving the company millions of 
> dollars."  The */PSCo Times/* noted that the award was "even more 
> impressive considering many of those employees were literally working 
> themselves out of a job."
>
>  
>
> On June 26th more than 700 past and present employees came together to 
> celebrate the final defueling of the reactor at Fort St. Vrain.  A 
> grand time was had by all on the front lawn of the now silent plant.  
> At this time, Del Hock, president, chairman and CEO of PSCo, presented 
> the 1991 President's Safety Award to the employees of the plant for 
> the most hours worked without a lost-time injury.
>
>  
>
> *_Decommissioning_*
>
>  
>
> Decommissioning of the plant--returning it to a safe and 
> non-radioacive site--began immediately after defueling was complete.  
> Decommissioning was expected to take 3 years.  Also at this time, 
> plans to convert the plant to natural gas were being considered.
>
>  
>
> In the October 4, 1993 issue, of the */PSCo Times/*, Bob Gunnerson, 
> decommissioning project engineer, reported that the last section of 
> the 15-foot thick concrete reactor top head (the top of the reactor 
> vessel) had been removed.  Diamond wire saws were used to cut the 
> tophead apart.  In all there were 12 pie shaped pieces, each weighing 
> around 110 tons, or in total, 17,500 cubic feet of concrete.
>
>  
>
> With the tophead removed, work could begin to remove the top of the 
> PCRV steel liner and then go on to the 1,500 graphite blocks which 
> made up the remainder of the reactor core (after the removal of the 
> fuel blocks during defueling).  The reactor was flooded with 
> constantly filtered water to provide as much shielding from the 
> remaining radiation as possible.
>
>  
>
> The reactor core support floor, weighing in at 340 tons, was removed 
> Feb 8, 1995.  With the reactor vessel still flooded, divers actually 
> had to swim under the core support floor to cut it lose from the core 
> support floor posts with torches.  It was then sectioned into two 
> pieces and lifted out, using the reactor building overhead crane.
>
>  
>
> *_Repowering_*
>
> (FSV rides again!)
>
>  
>
> Construction of the first gas turbine, a General Electric Frame 7 
> <http://www.gepower.com/dhtml/corporate/en_us/assets/gasturbines_heavy/prod/ms7001fa.jsp/> 
> called FSV Unit 2, was nearing completion in March 1996 and the unit 
> was test fired a few times.  Black & Veatch 
> <http://www.bv.com/bv/index.htm> was the primary contractor on this 
> unit.  On May 6, 1996, the unit came on line for commercial operation 
> at the "repowered" Fort St. Vrain.  Pubic Service initally billed the 
> plant as a "peaking unit capable of 130 megawatts (MW) of power."  The 
> June 24, 1996 issue of the */PSCo Times/ *quoted station director, 
> Marty Block, about the repowering:  "Start up of the combustion 
> turbine marked an important day for all of the employees here--and 
> certainly for all those who worked so hard over the years when this 
> was a nuclear facility. . .We're just glad to be back as a power plant."
>
>  
>
> Meanwhile, construction of the heat recovery steam generator (HRSG) 
> for unit 2 proceeded at a rapid pace.  The HRSG would take the hot 
> exhaust from the combustion turbine and make steam to power the old 
> steam turbine in the main plant building.  The HRSG also has 
> supplemental natural gas burners to provide additional heat during 
> times where peak load is required.  On March 21, 1998, unit 2 was 
> fired with the damper door open to the HRSG for initial heat up and 
> testing.  On May 5, 1998, with HRSG testing completed, steam was 
> admitted to the original steam turbine and the unit was syncronized to 
> the grid for the first time in 9 years.  At this point, FSV was 
> capable of about 230 MW of power total to the grid.
>
>  
>
> Construction of Unit 3, FSV's second gas turbine and HRSG, was 
> completed by January 1999 by principal contractor, Utility Engineering 
> <http://www.ueplaza.com/>.  Unit 3 was started up in simple cycle 
> (without the HRSG) on January 12, and syncronized to the grid.  On 
> April 24, the unit was fired in combined cycle and the steam turbine 
> was syncronized to the grid for the first time using unit 3 steam.  
> Now FSV was capable of just over 500 megawatts on a cool day.  (The 
> units outputs are highly effected by the ambient temperature.)
>
>  
>
> Construction of FSV Unit 4, the third and final gas turbine and HRSG, 
> was begun in the summer of 2000.  First fire of unit 4 was early May 
> 2001.  Utility Engineering was also the primary contractor for this 
> unit and The Industrial Company (TIC) <http://www.tic-inc.com/> was 
> their principal constructor.
>
>  
>
> On October 2nd, Public Service Company of Colorado officially became 
> Xcel Energy <http://www.xcelenergy.com/>.  Xcel Energy was the result 
> of the merger of New Centuries Energies and Northern States Power on 
> August 18th.  Headquarters for the new company are in Minneapolis.  At 
> this time, Xcel Energy had 11,800 employees in 12 states and served 
> 3.1 million customers.
>
>  
>
> In February 2001, Fort St. Vrain exceeded the total output generated 
> by the plant during the nuclear days.  This was a bittersweet date for 
> those who were at FSV in those days.
>
>  
>
> On April 25, 2001, unit 4 was put on the turning gear in preparation 
> for first fire.  Unit 4 has a selective catalytic reduction system 
> (SCR) for reducing stack emissions of the oxides of nitrogen (NOx).  
> The SCR was manufactured by Mitsubishi Heavy Industries 
> <http://www.mhi.co.jp/indexe.html>.  First fire was a brief flame on 
> the 28th.  A sustained flame was attained on the 29th and on the 30th, 
> and the unit was run for about 4 hours at full speed and no load.  As 
> with the first two combustion turbines, these events began the arduous 
> task of combustion tuning (for most stable flame and lowest 
> emissions), steam blows (to clean out the HRSG and steam lines), and 
> stack certification testing (to certify the stack emissions monitoring 
> system).
>
>  
>
> On May 21, 2001, unit 4 was put into service for the first time, 
> purely to produce power for the grid.  It ran in simple cycle and full 
> load during the combined cycle startup of unit 3 as FSV began putting 
> the other units and steam turbine back on line for the summer.  On May 
> 22nd, unit 4 was put in combined cycle for the first time, supplying 
> steam to the steam turbine.  On May 24, 2001, unit 4 was pronounced 
> "commercial," bringing to a close the $283 million repowering of FSV.  
> On May 31st all 3 combustion turbines were running in combined cycle 
> mode, supplying steam to the old steam turbine, for the first time.  
> The new plant uses 1800 psig and 1000 deg. F. main steam.  This is 
> believed to be the final configuration of the Fort St. Vrain power 
> station.  The plant is now rated at 720 megawatts.
>
>  
>
>  
>
> ----------------------------------------------------------------
>
> Sander C. Perle
>
> President
>
> Global Dosimetry Solutions, Inc.
>
> 2652 McGaw Avenue
>
> Irvine, CA 92614
>
>  
>
> Tel: (949) 296-2306 / (888) 437-1714 Extension 2306
>
> Fax:(949) 296-1144
>
>  
>
> E-Mail: sperle at dosimetry.com
>
> E-Mail: sandyfl at cox.net
>
>  
>
> Global Dosimetry: http://www.dosimetry.com/
>
> Mirion Technologies: http://www.mirion.com/
>
>  
>
>  
>


-- 
Bernard L. Cohen
Physics Dept., University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245  Fax: (412)624-9163
e-mail: blc at pitt.edu  web site: http://www.phyast.pitt.edu/~blc