ML19351E039
| ML19351E039 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 02/24/1965 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E038 | List: |
| References | |
| NUDOCS 8011250502 | |
| Download: ML19351E039 (10) | |
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YANKEE NUCLEAR PGIER STATIO:1 i
OPHtATION REPORT No. h9 For the month of JANUARY 1965 J
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l Submitted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts February
, 196$
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1 This report covers the operation of the Yankee Atomic Electric Company plant at Rowe, Nbscachusetts for the month of January, 1965.
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Throughout the reporting period the plant operated at or near
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full rated capacity of 185 Mle.
On Janrary 9, the total cumulative gross
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generation passed the four tillion kilowatt-hour nark.
Two abnormal occurrences were experienced during the month, both dealing with the control rod drive mechanisms. On January 6, during weekly control rod exercising, control rod No. Ih f ailed te step in upon normal signal.
Following completion of the exercise program, attempts were again made to exercise Rod lh and indicating coil voltages were taken.
Position indicating lights, voltage measurenents and recorder flux readings all showed the rod to be functioning normally. The rod was exercised to the normal 810/8 inch position without difficulty, returned to the 90 /8 inch position and a second exercise performed again witn no d1111culty.
av cue time of the incident the cause was thought to be improper closing of individual disconnect switches on the back of the main centrol board.
A similar abnormal occurrence with control rod No.10 uas
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experienced on January 13 No.10 failed to step in twice upon normal signal from the full out position of 90 0/8 inches.
The pull down coil
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was energized for one inward step and then de-energized. The rod was then stepped inward one step at a time to the 810/8 inch position and returned to the 90 /8 inch position without difficulty. A second exercise without any use of the pull down coil was made, again with no abnormalities noted.
8 occurrences has been postulated, although it is probably significant that At the present time no firm theory as to the cause of the abcve these same control rods, Nos.10 and Ih, were involved in a somewhat sinilar series of events in September, 196h. At no time during any of these abnormal occurrences has there been any question of the ability to shut the reactor down, if required.
In the present core only half of the twenty-four control roda are required in orde" to bring the reactor sub-critical. It is expected that a thorough inspection of the drive trairs 73 of these two rods will be made at the next refueling.
Particular emphasis EJ will be placed on crud buildup withi.n the mechanism, the cordition of the travel housing, the chaft and the drive shaf t locking cap.
Continuous monitoring of vapcr container leakage has indicated a leakage rate of 11.8 SCF/ hour extrapolated to 15 psig for the period December 17,196h to January 16, 1965. The extrapolated rate for Core IV operation to date has been 16.3 SCF/Fo tr.
Late in the month an air charge to the vapor container was made increasing the absolute pressure by approri-mately 1" Hg.
The increased pressure will be maintained for a period to determine the effects of a higher initial pressure on leak rate data.
On January 26, a vapor container inspection was made. The temperature of the inlet gipes to both pressurizer code safety valves was found to oe less than 250 F thus indicating gas blanketi.ng of the lead pipes with nearly zero valve leakage. Consideration is being given to providing for continuous venting under the safety valves.
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No plant shutdowns or reactor scrams occurred during January.
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. Plant bbintenance The following is a summary of major activities carried out by the' plant maintenance staff during January.
1.
Removed, cleaned and tested one pressurizer capillary tube.
2.
Inspected all valves and fittings under the generator for hydrogen leakage.
3.
Repaired a leak in the cooling water supply to the service air compressor.
h.
Repaired a leak at the feed inlet to No. 2 boiler feed p2mp, 5.
Drilled and cleaned three charging pump rams.
6.
Refaced seat and lapped condensate line relief valve in water
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treatment room.
7 Installed an air preheater around the incinerator roto-clone.
8.
Installed water meters in the spent fuel pit and ion exchange pit fill lines.
9 Cleaned the af tercooler on No.1 control air compressor, S
cleaned trap and installed new one inch gate valve.
10.
Installed a new pin that had been bored for grease fittinga in the spare vapor container polar crane hook, stored in the warehouse.
11.
The unit ersal handling tool was inspected.
12.
A leak in the safety injection tank heatir.g coil was discovered.
O All condensate was dumped until the spare coil could be cut into service.
13 Lubrication was carried out as scheduled, lh. The center ram packing box gasket of No. 2 cnarging punp was renewed.
15 No. 3 pressurizer heater experienced a cable connector failure.
The heater itself was found to be in good operating condition and was, therefore, reconnected such that it may be operated at 2$ Ed.
16.
No. 2 service water pump was inspected and paanted.
17 Progressed with machining of spare control rod drive shaf ts.
- 18. Repaired leaking No. 2 control air compressor discharge valve.
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- 19. Repaired leaking No. 2 control air tank relief valve.
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- 20. Inspected the plant warehouse fire protection system and rescated the deluge valve.
Chemistry Early in the reporting period oxygen levels in the min coolant varied between undetectable and 20 ppb. On January 20, the main coolant oxygen levels were measured at 100 ppb. This relatively high level was traced to a plugged capillary vent line frca the pressurizer which was subsequently freed. During the period of high oxygen, control rods were exercised, the coolant boron concentration was reduced and the pressurizer level cycled. On January 21, and for the balance of the reporting period the coolant oxygen levels were below detection.
During the month the main coolant Iodine-131 level was measured at 1.h x 10-5 uc/ml; the I-131/I-133 atomic ratio was 0.h7 t
U' Coolant boron concentration decreased from 302 ppm at the beginning of the reporting period to 155 ppm at month's end.
An analysis of the spent fuel pit water made during the period indicated :
pH 6.5 Specific Activity 1.1 x 10-5 ucfn1 8
Conductivity 1.2 m-mhos boron 71 ppm During the month the main coolant crud level was measured at 0.30 ppm. This data was recorded following a main coolant boron dilution and subsequent control rod motion.
As part of the continuing main coolant crud study, th ce successive crud samples were collected over a six minute period and crud level determined.
A 12% deviation was noted for the samples.
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A typical main coolant crud analysis performed on January 15, 1965 indicated:
Cr - $1 2.$ x 1 dpa/mg Fh - 5h 1.3 x 1 dpm/mg Fe - $9 9.6 x 1 dpm/mg Co - $8 3.8 x 1 dpm/mg Co - 60 1.h x 1 dpm/mg Hf - 181 2.7 x 1 dpm/mg In - ll6m 9.7 x 10 dpm/mg A typical main coolant gas analysis performed on January 7,1.965 indicated:
Xe - 135 h.9 x 10-2 uc/cc gas
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A-h1 8.9 x 10-1 ue/cc gas
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-h-The insertion of the Boral poison rack in the spent fuel pit x
brought about the initiation of corrosion test program. During the month a 180 day progress report on test results was released indicating the following:
1.
The corrosion rate of five aluminum control samples continuud to decrease and at the end of the test period was measured 2
at 0.3 mg/dm /mo.
2.
The defected Boral specimens continued to gain weight but at a reduced rate. At present the weight increase is approximately 2% of the total specimen weight. 80% of the weight gain is permanent and related to the B C-Al matrix.
h It has, therefore, been concluded that thus far no corrosion problems exist in the BgC-Al matrix.
I;uring the month a 90 day study of the corrosion resistance of Inconel in cold, borated, oxygenated water (refueling conditions) was 7 3
'V c ompleted.
Based on the minute changes in specimen weights and the absence of soluble nickel and soluble chromium in the test solution, it has been concluded the Inconel is resistant to chemical attack under Yankee shutdown chemistry conditions.
Reactor Plant Performance S
was issued for comments to cognizant personnel.
During the month a proposed Core IV-V refueling inspection program The empirical correlations used to predict the conditions at which departure from nucleate boiling (DNB) would occur are unable to differentiate between point values of heat flux and average values of heat flux from the core inlet to the point. Core data must be analyzed using both value of heat flux (point value and average to the point) in evaluating the margin to DUB. We have reported DNBR values using both
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types of heat flux evaluation this month for comparison.
DNBR = 2.6h For Average Heat Flux Occurs at 90" DNBR = 2.75 For Point Heat Flux Occurs at 75" Turbine Plant Performance Since October,196h, a trend towards poorer secondary plant performance has been detected.
Presently the total change observed is approximately lh6 amounting to 8 N. Since October, the changes observed t
are as follows:
1.
E /Wo ratio (heat rate) varies statistically with data t
and the mode of operation but the plotted data clearly defines a trend with time.
2.
Feedvater heater No. 1 terminal temperature difference has increased approximately 20F and the feedwater temperature
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leaving the heater has fallen off 20F.
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3.
Nos. 2 and 3 feedwater heater performance has also gradually
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fallen off.
Gross generation for the month of January,1965 was 137,967.1 Mde this being the highest monthly total achieved thus far amounting to an essentially 100% use factor for the period.
Instrumentation and Control Following is a summary of major activities carried out by the plant Instrumentation and Control group during January.
1.
Recalibrated the pressurizer temperature system.
2.
Repaired the primary stack gas radiation monitor.
3.
Recalibrated the light narrcw range main coolant temperature
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channels.
h.
Prepared a conceptual design on a monitoring system to measure water level in the react:r vessel during head lif ting operations.
5 Checked the calibration of the plant area monitore, 8
6.
Performed normal preventive maintenance on miscellaneous primary and secondary plant equipment.
7 Tested the spare main coolant flow transmitter differential transformer.
8.
Assisted in the installation of new air particulate measuring systems at off-site monitoring stations.
9 Repaired and recalibrated the spent fuel pit thermometer.
Health and Safety During the month of January,1965, no drums of radioactive waste were prepared or shipped.
Liquid wastes containing a total activity of 0.05 me were dis-charged during January. Gaseous wastes containing an estimated 36 mc of activity due to radiochemistry sampling were discharged during the same period.
A review of the waste disposal releases for the yaar 196h, is as follows:
1.
Idquid - Total activity of 2.oh5 nc.
2.
Gaseous - Total activity of 1.02h curies.
3 Ion Exchange Pit Ioakage - 1,127,559 gallons containing a total activity of 8.032 me.
h.
Solid - Prepared h65 drums containing a total activity of
_s 101.219 curies.
- Shipped 507 drums containing a total activity of 9$.280 curies of which 91.895 curies were icn exchange resins.
A radiation survey of the "non-radioactive" pipe chase revealed two local hot spots on the shield tank cavity fill and drain line. These were 700 mr/hr contact at the blank flange on the south end, and 2800 mr/hr contact near the vapor container penetration. Contact levels on the remainder of the line were 10-h0 nr/hr. General area levels in the vicinity of the hot spots were 60-150 nr/hr. The pipe chase was therefore posted "High Radiation Area - Work Permit Required."
Radiation levels on a bent control rod drive shaft that had ser
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service in Core III were 30-300 mr/hr along the shaf t from cap to dashpot end and 7.5 R/hr on the dashpot. Attempts at reducing the levels by soaking the dashpot in a decontaminating solution have, to date, failed. This drive shaft is scheduled for salvaging by recovering the dashpot and coupling and replacing the bent shaft section with a new unit.
Personnel exposures for Yankee plant personnel as measured by S
film badge for the month of January, 1965 were:
Average for all station personnel
= hh Maximum individual exposure
= 200 Plant Operations Attached is a summary of plant operation statistics for the month rx of January, 1965 and a plot of daily average plant load for the same period.
'J The figure, " Reactor Plant Availability" has been added to the operating statistics section of the report. This figure will indicate the overall availability of the primary plant and discounts any shutdown time attributed to the secondary plant.
Corrections The Station Service (To Date) figures should be corrected to read:
September, 196h 19,$9P,351
- October, 196h 19,798,h51
- November, 196h 19,798,h51 December, 196h 19,798,h51 The Station Service (Year) figure in the December, 196h report should be corrected to read:
December, 1%h 1,753,200
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YANKEE \\TOMIC ELECTRIC COMPANY -- OPERATLNG SUiOIARY ELECTRICAL MONTH YEAR g _DAT C Gross Generation KWH 137,967,100 137,967,100 h,1C1,083,300 Sta. Service (While Gen. Incl. Losses)
WH 8,201,573 8,201,573 267,863,68h Net Generation KWH 129,765,527 129,765,527 3,813,219,616 Station Service 5.9h 5.9h 7.01 Sta. Service (While Not Gen. Incl. Iosses)
KRH 0
0 19,798,h51 Ave. Gen.
For Month (7hh HRS)
KW 185,h39 Ave. Gen.
Running (7hh HRS)
W 185,h39 PIANT PERFORMANCE Net Plant Efficiency 29.16 2 9.16 Net Plant Heat Rate Btu /WH 11,703 11,703 Lbs. Steam / Net WH 13.8h 13,8h Circulating Water Inlet Temp.
Maximum F
h3 Minimum F
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'd Plant Operating Factor 99.67 99.67 69.8h '
Reactor Plant Availability 100.00 100.00 Sh.55 NUCLEAR 10 NTH CORE IV TO DATE Times Critical o
19 3hh Hours Critical HRS 7hh 3573.09 31,373 58 Times Scrammed 0
5 h
Equivalent Reactor Hours @ 600 E t HRS 7hl.56 3h01.85 22*290*55 Average Burcup of Core WD/mtU Control Rod Position at Month Ehd Equilibrium at 600 Nt
$27 F Tavg REGION MONTH TOTAL BUrUJUP Group A Rods out-inches 85 7/8 Group B 88 7/8 INNER 988,79 13,092.h6 Group C 88 7/8 MIDDLE 1102.67 9959.61 Group D 88 7/8 OUTER 676.6h 3399 75 E-6 811.h9 25,865 59 Bo ri.n 155 ppm
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O YANKEE ATOMIC ELECTRIC COMPANY DAILY AVERAGE LOAD for January, 1905 e
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