ML19351E140
| ML19351E140 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 09/30/1963 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| References | |
| NUDOCS 8011250658 | |
| Download: ML19351E140 (7) | |
Text
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b YANKEE NUCLEAR FORER STATION OPERATION REPORT NO. 32 For the month of AUGUST 1963 O
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Subrd.tted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts September 30, 1963 0
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. o This report covers the operation of the Yankee Atomic Electric Company plant at Rowe, Massachusetts for the month of August 1963.
p Throughout the reporting period plant operations were normal and routine. The last phases of the core life extension were realized as plant electrical output dropped from 11h We at the beginning of the month to 92 We at the end of the reporting period. The load reduction experienced in-general followed the expected burnup curve.
Paparations for the forthcoming refueling outage reached an accelerated pace during August. Procurement and fabrication of tools and equipment required for the shutdown was essentially complete. Final operational procedures and maintenance lists were issued.
A boral-aluminum rack to permit storage of Cores II, III and IV in the spent fuel pit was delivered to the site in August. However, weld defects were discovered in the clad material of the boral plates, the poison medium, and use of the rack will be deferred until repairs can be effected or until it is demonstrated that the defects are not detremental. To facilitate storage of Core II fuel scheanled for discharge in September an Q
aluminum rack whose design approximates that of the present racks will be fabricated.
2h hafnium control rods were delivered to the site in August.
23 silver-indium-cadmium control rods utilized during Core I operation were shipped off site for disposal.
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- =tae== ecc=rrea a=rs=8 ^=c= t-Maintenance Following is a summary of major activities carried out by plant maintenance personnel during August.
1.
A valved pipe connection was installed between the 1-2 and 2-1 ion exchangers.
2 The flexible hose on the waste disposal incinerator was replaced.
3.
No. 1 and No. 3 charging pumps were repacked.
- h. The exciter brus'as were inspected and replaced as required.
5.
Preum%nry wiring for dividing control rod group 6 into two groups was installed.
6.
An electrical inspection of the turbine hall crane was completed.
7.
The cam switch on the left hand thrott_e valve was wired to the turbine start up panel.
8.
Replaced a leaking check valve on No.1 boiler feed pump.
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Installed preliminary wiring for the new pressurizer motor operated spray valve.
- 10. A new micro witch was moara.ed on the shield tank cavity jacking mechanism.
- 11. A faulty trip der'.ce on the station service air compressor was replaced.
12 The motor was installed on the fuel chute dewatering pump and the pump repacked.
- 13. The transformer oil ecolors were c13aned.
Ih. The relief valve on the seal water tank was repaired.
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Chemistry
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Throughout the reporting period main coolant oxygen levels remained below the point of detection.
Main coolant iodine-131 specific activity ranged between 6.3 and 8.h x 10-h pc/nl. Crud level measr amenta mads during the period ranged between 0.13 ppa and 0.hh ppm.
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The main coolant ammonia concentration was kept at an essentially constant value of 7 ppm until Augast 25 when withdrawal was initiated. At the end of the reporting period the ammonia concentration had dropped to 0.16 ppm.
A typical main coolant end analyfa made during August indicated:
Fe - 59 7.7 x dpm/mg Co - 60 1.1 x 10 dpm/mg 7-l Co - 58 37x dpm/mg
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Cr - 51 7.2 x dpm/mg
>h - 5h 5.9 x 105 dpm/mg A typical main coolant ge.s analysis made during the period indicated:
A - h1 2.1 x 10-1 pc/cc 2.9 x 10-1 :e/cc Xe -
1.71 J1c j /cc Xe Reactor Plant Performance Following removal of ammonia from th3 main coolant system on August 25, a gradual reactivity 1cas of 0.3 % 6, 6 occured over a five day period.
?tior to ammonia removal the core reactivity depletion rate remained essentially constant at 0.13 % 6 P/ week.
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The following were deternd.ned by means of in-core instrumentation measurements at a power 2svel of 365 Nt and all rods at the fully withdrawn position of 88 7/8 inches.
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2.8 F6H
!!Lnimum QDNBR 5.5 Turbine Plant Performance On August 29 the circulating water system discharge pipe vacuum was lost resulting in a 1.5 me decrease in gross generation. Attempts to restore the vacuum with the temporary air removal pump were unsuccessful.
As discussed in previous reports the operational difficulties within the system have been traced to hydraulic instability in the condenser discharge (Vl line. The proposed modifications, which will be made at the refueling shutdown, included the installation of additional air renoval taps at selected points on the discharge line. The modifications are directed towards improving the venting capacity of the system and thereby limiting the anount of entrapped air within the discharge piping.
The results of a recent fesdvster heater termlhal. difference measurement were:
V 101 We @ 1.8 " Hg Back Pressure 285 psig throttle No. 1 Heater h.80F No. 2 Heater 12.20F 6
No. 3 Heater 3.2 F To bring No. 2 heater within its design range the manufacturer has recommended a slight charge in the heater vent. This modification
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will be made at the refuelics shutdown.
Instrumentation and Control During August the balance of the work load of this group was devoted to preparations, for the refueling shutdown.
A complete set up and test of the refueling nuclear instrumentation was made. Underwater' inspection equipment has been inspected and made ready for service.
Health and Safety During August liquid waste containing a total activity of 0.08 cc was discharged from the plant. Gaseous waste containing an estimated 150 me was discharged during the same period.
. 30 druns of non cocibustible radioactive waste containing a total (7
activity of 688 mc were prepared in July.
52 drums with a total activity V
of 6.6 curies vere shipped off site for disposal. The bulk of this activity
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(5.6 curies) was in two drums. containing eight vessel irradiation specimen V
. hole plugs.
During the month 23 Core I control rods were shipped off site-for' disposal at the AEC cperated land burial site in Oak Ridge, Tennessee.
Radiation levels measured on contact with the cask were generally 100 -
300 mr/hr with a-small area indicating 500 - 1000 r /hr.
Ievels at three meters from the cask-were 20 - 35 mr/hr. Contamination levels were 2
200 - 1200 dpm/ft, Radiation levels measured after loading of' cask into the' structural steel crash fram were h - 55 mr/hr at the sides of the gondola car opposite the -cask with 50 mr/hr and 10 mr/hr, the mar 4==
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. levels at distances of one meter and four meters respectively. Shipment wa? accomplished under a special I.C.C. permit with two members of the Ya;Jcee technical staff acting as couriers.
Personnel expcauresfor Yankee plant personnel as masured by film badge for.the month of August,1963 were.
' Average for'all station personnel 90 mr
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h0n mr Maximum individual exposure
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Plant Operations Attached is a summary of. plant operation statistics for the month of: August 1%3, and a plct of daily average plant load for the same period.
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TANIEE ATOMIC EIECTRIC CO;u'ANY - OPERATING -SUMARY AUGUE.T 1963 EIECTRICAL MO M YEAR TO DATE Gross Generation KWH 77,972,h00 830,78h,500 2,532,256,500 Sta. Service (While Gen. Incl. Losses)
M 7,063,997 56 123,538 186,880,105 Net Generation M
70,908,h03 77h,660,962 2,3h5,376,395
' Station Service 9 06 6.75 7.38 Sta. Service (While Not Gen. Incl. Losses)
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1,021,038 1h,989,876 Ave. Gen. For Month (7hh HRS.)
KW 10h,802 Ave. Gen. Running (7hh HRS.)
KW 10h,802 PLANT PERFGMANCE Net Plant Efficiency 26.00 28.h1 Net Plant Heat Rate Btu / M 13,126 12,012 8
Ibs. Steam /NetKW 4
Circulating water Inlet Temp.
Maximum F
70 i
Minimm F
$1 Plant Operating Factor 67.89 86.58 69.17 MONTH CORE II TO DATS l
NUCIEAR Tisms Critical 0
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. 300 Hours Critical HRS 7hh.00 0,251.35 21,h98.78 0
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l Times Scrassmed Equivalent Reactor Hours @ $ho MWt HRS 505.1 7,259.8 15,176.9 Average Burnup of Core NWD/mtU
$h6.h 7,853.5 Control Rod Position at Month End Equilibrium at 320 Mdt and h51.5 F T avg.
Group 1 Rods cut-inches 88 7/8 Group 2 88 7/8 Group 3 88 7/8 Group h 88 7/8 Group 5 88 7/8 i
Group 6 88 7/8
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DAILY AVERAGE LOAD i-for l
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OPERATION REPORT NO. 31 For the month of
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YANKEE A'20MIC ELECTRIC COMPANY Boston Massachusetts August 28,1%3 O
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us This report covers the operation of the Yankee Atomic Electric Company plant at Rowe, Massachusetts for the month of July 1963.
At the beginning of the period the plant was operating at a power level of 133 We and a main coolant average temperature of h880F. Until July 17, plant operations were normal and routine with the effects of the core extension program realized through gradual reductions of main coolant temperature and etation load.
On July 18, the plant experienced a reactor scram from a power level of 123 We followed by a trip of the Y-177 =9d Z-126 line breakers and the steam turbine throttle valves. Following the scram both a dropped rod and a low flux scram memory light were displayed. The low flow scram light resulted from the stopping of No. 2 and No. 3 n.ain coolant pumps after exciter trip. The dropped rod light is thought to have originated from a
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transient fault in on. of the six power range channels causing a " pip" in
'v) the downward direction and a rear. tor scram. Several channels have experienced this "pipping" throughout Core II lifetime. The source of the "pipping" is believed to be the deterioration of connector cables at the detectors in the vapor container. It is planned to replace all detector cables at the refueling outage.
Coincident with the scrum No.18 control rod failed to drop
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(V immediately. It remained in the withdrawn position for several seconds after the other rods had scrammed before falling into the core.
In order to check the possibility that this particular rod may have been withdrawn further than the others and so subject to drive shaft locking cap interference, a rod position versus indicating coil voltage check was performed on rods No. 17 through 20. All positions appeared uniform.
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As a further check', Rods 17,18 and 19 were withdrawn and dropped from their pre-scram height of 88 7/8 inches. All rods released together and dropped smoothly into their fully inserted position within the core.
With normal operating conditions of the control rod drive mchanisms assured, the reactor was brought critical and the generator was phased to the line, plant load being raised to 125 We.
The core lifetime extension program was in effect throughout the remainder of the period with gradual main coolant temperature and reactor power level reductions resulting in reactivity additions to corpensate for reactivity lost through burnup. At the end of the reporting period the plantwasoperatgF.at a power level of 115 We and a main coolant average temperature of h69 Two routine inspection tours of the vapor container were made 7-during July. In both cases no abnormal conditions were noted.
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O Preparations for disposal of the.23 Core I control rods were completed during the month.
Plant Shutdowns Shutdown No. 61-2-13 7/18/63 A four hour shutdown resulting from a reactor scram.
Reactor Scrams-Scram No. 38-2-8 7/38/63 A spurious reactor scram' from a power level of 123 We, The reactor scramed due to a transient fault in one O
of the six power range channels.
1 Maintenance Following is a summary of major activities carriedcout by plant maintenance personnel during July.
Q 1.
A leaking check valve on No.1 waste gas compressor was repaired.
2 the exciter brushes and inverter brushes were inspected and replaced where necessary.-
3.
The annual inspection of No. 2 battery motor-generator set was completed.
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- a. No.1 contro1 air comgre eor o111ever trir mechanism was cleaned and adjusted.
L No. 2 jacking pump was rewired and new hose installed.
6 No. 2 charging pump was repacked.
7.
The fire system air compressor was inspected and repaired.
8.
No. 1 control air compressor valves were replaced.
9.
A fixture for storing control rods in the shield tank cavity was fabricated.
- 10. Repairs and modifications to the universal hawiling tool continued during~the period.
- 11. Six of the 2.h KV A.C.B.'s were inspected.
12 The spare control rod drive coil stack was rebuilt and made ready for service.
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- 13. _ A defective bearing.was replaced on'the waste disposal ash
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. devatering pump.
. 1h. The 2h inch main steam line trap was. replaced.
15.
'A leaking' weld on the suction line of No. 3 charging pump was. repaired.
Chemistry Early in the period main coolant crud levels averaged 0.15 ppm with corresponding ammonia concentrations of 6 to 8 ppm. On July 17, the ammenia concentration dropped to 3.2 ppa and the crud level increased to
- 0.26 ppa. A correlation between the anunonia concentration and crud' level has been difficult to obtain. Further testing to establish possible mechanisms for'the ammonia-crud-relationship is planned..
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s Throughout the reporting' period main coolant oxygen levels
,. 1 remained below the point'of detection.
Main coo t iodine-131 specific activity which initially averaged 5 to 6 x 10- pc/ml increased to 2.2 x 10-2 pc/ml following the
' scram of July 18. -Subsequent operations resulted in a slow dec ase of the iodine specific activity reaching the pre-scram value of 6 x 1 pc/ml at
-- the end of the reporting period.
- A typical main coolant crud analysis made after the scram indicated:
Fe -_$9 1.5 x 106 dpm/mg i '
Co - 60 1.7 x 106 dpm/mg i
Co - 58 6.h x dpa/mg Cr - 51 7.1 x dpm/mg It1 - 5h 7.3 x dpm/mg_
Ag - 110m 5.0 x dpm/mg
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A typical main coolant gas analysis made during the period indicated:
A-h1 3.8 x 10-1 pc/cc Ie-135 1.1 x 10- pc/cc Ie-133 1.70 pc/cc Reactor Plant Performance Throughout the reporting period the core reactivity depletion rate remained essentially constant' at 0.15 % M3/ week. A slight reactivity loss was noted following -the plant scram, however, it was quickly regained following startup and a return to the expected depletion curve was realized in four days. No reactivity effects could be observed following changes-in the main coolant' ammonia concentration.
h' The following were determined by means of in-core instrumentation.
measurements at'a power level of h05 E t and all rods at.the fully withdrawn a
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.~ position of 88 7/8. inches:
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Turbine Plant Performance.
During the month' a decrease in the phnt thermal efficiency.was realized coupled with increases in plant heat rate and steam flow. - This reduction in plant performance can be attributed'in part to the loss of circulating water system dischargs vacuum but also to the increased circulating water inlet temperature at reduced plant loads.
The results of a recent Feedwater Heater Terminal Difference
-measurement were:
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.125 ETe @ 1.6 " Hg. Back Pressure h790F Tavg.
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- 2-12.6 F TD t
- 3 h.8CF TD Instrumentaticn and Control j.
O 1n 1 ate narch of e s Fear en inveet1 ation as to the eauee of "pipping" on some 'of the power range channels was initiated. Dudng a schedulaishutdown an inspection of the channel 6 detector, cables and
' connectors in thimble 7 was made. Considerable radiation damage had occurred to the jackets on the coaxial cables. Some repheement connectors were installed and the cables taped resulting in a marked decrease in channel 6 "pipping". A modified cable design has been developed and will be installed on all channels at the refueling shutdown.
Health and Safety--
Liquid waste with' a total activity of 0.2h m::-was discharged from the plent during July. Gaseous waste due primarily to' radiochemistry sampling containing an estimated 200 ac was discharged during the same-period. At all times the concentration of waste products discharged from the site was well below the maximum permissible.
Six drums of non combustible radioactive waste containing a total activity of 5.6h curies were prepared in July. Two of the drums containing eight vessel irradiation specimen hole plugs accounted for the bulk of the activity they being 5.6. curies.
Salvaging of the Core I ddve shafts was accomplished 'during the period.. An outside contracting firm was employed to cut off the dashpot.
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end of the shaft ~ and decontaminate the balance of the ' shafts for future reuse.
Radiation levels measured on the dashpots. - were 1-12 r/hr at one inch.
After removal of-the dashpots igeneral levels on the shafts were reduced to m.
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. 200 mE/hr. ' Sixteen ' dashpots were individually drummed and shipped off site-for disposal..Ievels en the remaining eight, which were also placed in drums, were considered too high for shipment and were conse-quently placed in a shielded section of the drum storage. area.
Personnel exposure for Yankee plant personnel as measured by film badges'for the' month of July 1%3 were:
h5 mr.
Average for all station personnel
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mmh = = individual exposure
-- 250 mr.
Plant Operations Attached is a summary of. plant operation statistics for the month of July 1963, and.a plot of daily average plant load for the :sams period.
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YANKEE ATOMIC ELECTRIC COMPANY - OPERATING'
SUMMARY
JULY 1963 EIECTRICAL MONT_H YEAR TO DATE 4
Gross Generation KWH.
91,630,800 752,812,100 2,h5h,28h,100 7
sta. Service (While Gen. Incl. Losses)
KWH 7,2h3,619 h9,059,$hl 179,816,108 Net Generation KWH 8h,387,181 703,752,559 2,27h,h67,992 Station Service 7.9 6.52 7 3h j
Sta. Service (While Not Gen. Incl. Losses)
KWH 23,$h7 1,021,038 1h,989,876 1
Ave. Gen. ' For Month (7hh HRS.)
W 123,160 Ave. Gen. Running (739.72 JIRS.)
W 123,872 1
PIANT PERFORMANCE 1
Net Plant Efficiency 26.92 28.68 Net Plant Heat Rate Btu /KWH 12,677 11,899 Lbs. Steam / Net KWH 15.20 1h.20
-m Circulating Water Inlet Temp.
i Mar 1=um F
68 CF h6 PH ninnna l
Plant Operating Factor 78.05 89.32 69.21 NUCIEAR MONTH COEE II TO DATE s
Times Critical 1
38 300 i
Hours Critical HRS 7h0.68 7607 35 20,75h.78 Times Scransnod 1
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Equivalent Reactor Hours @ $h0 MWt
-HRS 580.7 675h.7.
Ih,671.8
. Average Burnup of Core MWD /mtU.
628.2 7307.1 i
Control Rod Position at Month End Equilibrium at 392 Mit h69 F Tavg.
Group 1 Rods out-inches 88 7/8 l
Group 2 88 7/8 L
Oroup 3 88 7/8 Group h 88 7/8 Group 5 88 7/8 oroup 6 88 7/8 i.
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