ML19345A337
| ML19345A337 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 01/17/1962 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19345A335 | List: |
| References | |
| NUDOCS 8011190114 | |
| Download: ML19345A337 (10) | |
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YANKEE NUOLEAR POWER STATION-
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OPERATION REPORT NO. 12 For the month of
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Subrdtted by YANKEE ATOMIC ELECTRIC COMPAh"I Boston Massachusetts j
January.17, 1962 I
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This report covers the operation of the Yankee Atomic Electric Company plant at Rowe, Massachusetts for the month of December,1961.
The plant was cperated at a reduced power level of 120 IGT gross 1
electric until December 18, at which time load was increased to 150107 gross electric, in anticipation of the annual electrical system load peak. The turbine control valve noise and vibration, experienced during the months of September, October and November, continued intermittently but was not as pro-nounced or continuous as during the fall months. Testing and investigation of the cause of this difficulty continues.
On December 21, the plant tripped due to a spurious reactor scram.
This scram was initiated by a false main coolant low pressure signal, caused by a varying ground in the air particulate monitoring equipment. Feedback through the inverter, which was _ connected to the vital bus, resulted in er-ratic pressure indications eventually reaching the low main coolant pressure scram set point. Isolation of the trouble allowed rephasing of the plant to the electrical system some three and one-half hours later. A power level of 150 W electric was successfuny re-established in approximate 2y four hours, by complete withdrawal of all control rods from the core. Approximately seven hours later, er during the xenon burnout period, power level remained at 150 W electric, but with the controlling group inserted some twenty inches into the core. Approximately thirty hours later, or upon return to equilibrium xenon conditions, all control rods had been returned to the "all-out" position and power level.had been reduced to the 136-lh0107 gross electric range while maintaining a normal average main coolant temperature of 51hoF. Some twenty-four hours later, a small unexplained gain in reactivity occurred, and for a period of scne eight hours power level was again increased to approximately 150 IGl electric with a corresponding main coolant temperature of 513 F.
After operation at full power, for this short period of time, nain coolant temper-ature began to decrease requiring load reduction to lho 10! electric in order tc maintain a 51h F main coolant tenperature. The remaining seven days of the month saw a nominal power level of 1ho IGl gross electric while maintaining a nominal 512 F average main coolant temperature. The above scram produced a loss and slow gain of reactivity in a nanner and magnitude similar to that previously noted from the time of the h000 EFFH burnup point to the present.
Operation at various base loads continues to provide information on magni-tudes and characteristics associated with the phenomena of gains and losses of reactivity.
Eighteen fuel assemblies for use-in Core II were delivered to the plant in December. A total of fifty-two Core II fuel assemblies have now been received.
The continaed vapor container leakage testing program, consisting of leak rate tests, searching for leaks, and correcting those discovered, has now shown that Yankee's vapor container leak rate monitoring system is re-liable and accurate and that the contairsent is essentially leak tiEht. The most recent test period of thirty-five days duration revealed a leak rate for
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.15 psi internal pressure, of approximately 20 cubic feet per hour as measured-at M,andard conditions, well within the design objective of 70 cubic feet per hour.
Preparation for the first refueling period continues in the form of preliminary work schedules, n itten operating procedures, establishing end of Core I life and start of Core II testing programs, fabrication of new tools and fixtures, and checking of other miscellaneous maintenance equipment.
Only one reactor scram occurred in December as mentioned above:
Scram No. 30 12/21/61 - A scram from a power level of h85 to7t resulting from a false main coolant low pressure signal which was caused by a varying ground in the air particulate monitoring equipment. The plant was dis-connected from the line for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> and 20 minutes as a result of this spurious scram.
One plant shutdown occurred in December, caused by the above reactor scram and turbine trip.
Shutdown No. h7 12/21/61 - a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> and 20 minute outage result-ing from a reactor scram and turbine trip.
(see Scram No. 30).
Plant Maintenance Following is a description of the major maintenance activity during December:
1.
The spent fuel pit wooden floor area and storage racks were reinstalled in the pit after application of the phenolic resin liner. The pit elevator was re-aligned and the fuel manupu-lator crane was checked. Certain carbon steel parts of the fuel laydown mechanism were replaced with stainless steel while other stainless steel bearings were found to be rusting and were re-placed with aluminum bronze bushings.
2.
The No. 3 charging pump rams were inspected and found to be bad-ly wcrn. These rams were ground arid reinstalled for a period dile a spare set are -being plated and readied for installation.
3.
Inspection of the discharge check valves on the vaste gas ccm-pressors revealed broken spring guides in both valves. New guides were fabricated and installed.
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Rebuilt plungers ard new packing were installed in Nos. 1 and 2 charging. pumps.
5.
No. 2 instrument air conpressor valves were inspected and new diaphragm seats and feather springs were installed.
6.
The new safety injection tank heating coil parts were received and stored until the refueling period, at which time they will be installed into the tank.
In addition to the above, routine preventative maintenance procedures 1
were carried out during the month.
Turbine Plant Performance Two calorimetric runs were made during December, one at 120 Ed l
electric and the second at 1ho K4 electric in order to check the Ed electric and condenser backpressure versus Ed thermal output correlation.
A caeck of the three feedwater heater terminal temperature differ-
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ences at 150 K4 electric showed that the differences remain 2 to 3 times l
nigher than specification. Testing and analysis of the difficulty continues.
i Condenser tailpipe vacuum difficulties reappeamd during the month, the syphon effect being lost twice; once due to the reduced pond elevation and once for an unexplained reason.
Proper vacuum was, however, re-estab-lished upon shutdown of one-half of the condenser circulating water flow.
4 Reactor Plant Performance 4
The following values were deter:r.ined by neans of in-core instru-nentation neasurements at a power level of 392 Edt and a Group 2 rod position of h2 inches:
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(Heat Flux) 3.6 q
(Coolant Rise) 2.h j
FdT DNB ratio 3.6 A collection of similar in-core instrumentation data at a power level of h30 Edt with all control rods out of the core at 90 inches showed:
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F (Heat Flux) 35 q
F (Coolant Rise) 2.9 T
DIG ratio 2.8
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l During the power level increase frce 120 IMe to 150 IMe, d T/ d Power measurements were made. ' Reduction of data-showed a value of 0.079 F/IMt at h1h.8 1rdt.
Extension of Core I lifetime was also investigated during the month.
This effort consisted of calculating optium step reductions of T average and power level to the economic point of plant shutdown.
Chemistry On December hth, a leak developed in the safety injection tank heating coil, resulting in a boron concentration buildup to 26 ppm in the secondary side of the four steam generators. Eorated water entered the heating coil through the leak area and was returned to the secondary system through the steam drip system. A continuous 1% blowdown was established reducing the concentration to 8 ppm in approxinately two days. The heating coil condensate is now directed overboard until replacement of heating coil's is accomplished during refueling.
Main coolant oxygen levels remained below the detection point during ed from h.3 x 10-2 pc/n1 Decenber.
during reduced power level operation to 6.7 x 10-2 Main coolant specific activity levels
.pe was increased.
Ea-ly December found Iodine - 131 concentration increased to 1.3 x 10-3 sc/ml, up from a November average concentration of 1.h x 10-b pc/ml.
The I-131/I-133 atomic ratio for the corresponding period also increased frca a value of 1.2 to 3 3.
Mid month saw the Iodine - 131 concentration move up to 1.9 x 10-3 se/ml with a I-131/I-133 ratio increase to 3.8 The fission product study initiated in late November continues to be carried ferward with prelininary results indicating a possibility of niner fuel defects.
Secondary side steam generator activity measurenents centinue to indicate only background levels.
Main Coolant crud analysis:
Fe - 59 2.2 x 1 dpm/~
Ag - 110 6.8 x 1 dpm Co - 60 6.9 x 1 dpn Co - 58 9.9 x 1 a
Cr - 51 h.h x 10 d Mn - 5h 2.3 x 1 d
mg Crud level 0.11 ppm The results of a main coolant gas analysis indicated:
h.3 x 10-1 h.1 x 10-2,ne/cc gas A - hl c/cc ga, Xe - 135 Xe - 133 1.h x 10-2 Ic/cc gas Kr - 85m 1.9 x 10-2 sc/ccgas
5.
Health and Safety
-Liquid waste with a total activity of h08 Ac and gaseous vaste
. with a total activity of 260 pc were discharged during December. Concen-trations of wasto products discharged from the site were well below the maximum permis? tole level at all times.
No solid waste was shipped from the site during the month.
Radiation level above the ion exchang'e stcrage pit was reduced from 1.5 mr/hr to 0.1.nr/hr by the addition of-two feet of water i.. the pit.
Following is a summary of contact radiation levels measured on cer-tain primary auxilary building equipment for purposes of determining activity build-up with time. Values do not,-therefore, necessarily represent a general radiation. level-to be associated with equipment location. No read-ings were taken on equipment within the vapor container during the month.
Radiation Level On Contact Main Coolant bleed line at trip valve.
200 to 1100 nr/hr Low Pressure Surge Tank 3.5 to 11 r No. 1 Charging Pump 10 - 18 mr hr No. 2 Charging Pi:mp 5 - 7 mr/hr No. 3 Charging Pump 2-hmr/hr Charging Line (in pipe chase) 5-9mr/hr No. 1 Purification Pump Drain Line 3 r/hr.
No. 2 Purification Pump Drain Line 1.5 r/hr Shutdown Cooling Pump 100 to 550 mr/hr Shutdown Coolir4 xchanger 30 to ho cr/hr r
Shutdown tooling Line (in pipe chase) h00 to 600 nr/hr Chemical Injection Line (in pipe chase) 1 - 5 mr/hr '
Radioactive waste disposal system on contact readings were measured as follows:
Radiation Level On Contact Activity Dilution Decay Tank 20 to.h00 nr/hr Waste Hold Up Tank 100to130nr/hr Drum Storage Area 30 to h0 mr/hr i
Health physics preparation for the coming refueling program con-tinued with discussion of control of internal radiation exposure ariuse of respiratory protective equipment being held at the regular monthly safety meetirg. The refueling period health physics activities were also discussed I
with the Yankee health physics consultant.
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For the month of November, 1961, the maximum personnel exposure as measured by film badges was 370 mr while the average for all statica person-nel was 19 nr.
. Continuous monitoring of off-site. airborne activity during December indicated levels consistent with pre-operational values.
Design Changes No design changes were made in the plant during the month of
- December.
Plant LTganization Recent additions to the plant organization include:
1.
A technical assistant in the Reactor Engineering Group.
2.
A training student in Health Faysics.
3.
A clerk in stores.
Total plant personnel now numbers 68 not including the plant guards.
In Plant Training A sponsor company engineer completed a three month training assign-ment at the Yankee plant in mid December.
The Consumers Power Company health physicist was in residence at Yankee for approximately two weeks during the month for familiarization ahd discussion of health physics practices and procedures.
Plant Cterations Attached is a plot of daily average plant load and a summary of plant cperating statistics for the month of December.
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YAllKEE AT0!!IC ELECTRIC COMPANY OPERATING ' SUri'tARY
-MONTH: DECIG1PER 1961 Month to Date Gross Generation KWH 96,660,h00 961,3h7,300 Station Service (While Gen. inc. Losses)'
KWH 7,160,528
'77,532,082 Not Generation KWH 89,h99,872 883,815,218 Station Service -- Percent 7.h1 8.06 Station Service (While Not Gen. inc. Losses)
'KWH 22,573 10,091,718 Ave. Gen. --- For Month (7hh Hrs.)
Net KW 120,296
- Ave. Gen. --- Running (7h0.7 Hrs.)
Net KW 120,831 F uivalent Reactor Hours at 392 K#f HRS 760.h 7626.8 4
Equivalent Reactor Hburs at h85 M#f HRS 61h.6 616h.8 s
Average Burnup of Core-K4D/ Tenne 5,965 Use Factor -- Percent 82.6 68.8 Circulating Water Temperature - F Max.
F h0 Min.' F 3h Control Rod Position at Month End --
(Equilibrium and Power at Ihl lidE Gross 0
and an Average Main Coolant Tenperature at 513 F. )
Group 1 -- Rod Out Inches --- - 90 Group 2 --
90 90 Group 3 --
Gioup h --
90 Group 5 --
90 Group 6 --
90 1
252 Times Critical Hours Critical 7hl.87 9833.01 Tines Scrammed 1
30 30.0 Ret Plant Efficiency -- Percent 1,178,h92,000
~Ctaan Flow - Lbs.
Lhs. Stean/ Met KWH ~_
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DAILY AVERAGE LOAD for DECEMBER, 1961 150 -
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1-17 62 1-1942 1293 buton 16, lisse.
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REFERRED TO DATE RECE!YED SY DATE
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