ML19351E149
| ML19351E149 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 06/21/1963 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| References | |
| NUDOCS 8011250667 | |
| Download: ML19351E149 (8) | |
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YANKEE NUCLEAR P7 DER STATION OPERATION REPORT NO. 29 For the month of MAY 1963 p) m O
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YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts June 21, 1963 A
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This report covers the ^ operation of the Yankee Atomic Electric
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Company plant at Rowe, Massachusetts for~ the month of May 1963 Plant conditions at the beginning of.May saw the power level at 167 We with a main' coolant average temperature' of $1hoF. -Continued design difficulties with the circulating water system discharge siphon limited plant output to 166-168 We.
On May 9 all control rot reached the upper program withdrawal limit of 88 7/8 inches. For the next six days core reactivity depletion rate was essentially zero with only slight changes noted uhile varying main. coolant purification. However, this was followed by a period of
- higher than normal depletion rate in which plant electrical output was
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reduced to 162 We.
May 16 saw the beginning of the core extension program. With the four turbine control valves at the full open position, reductions in '
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cooled average temperature, thereby resulting in reduced steam flow and a cc...s):anding decrease in plant electrical output.
Hydrazine was added to the main coolant system on May 20. As experienced previously; primary system pH and NH3 concentration were increased by hydrazine. injection followed by n gradual increase in power h'.
level (160 We - 168 We)' and main coolant temperature (5080F - 51h.59).
For approximately 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> following hydrazine. addition a slow reactivity gain of v 0.3% 6p was experienced. The gain was reflected in increasing main coolant temperature until rod insertion _was required to maintain T average at 51h F, Group II control rods reaching a low limit of 72 O/8. inches.
For the next three days core burnup was followed with rod withdrawal-until-on May 2h all rods were again at 88 7/8 inches.
Late in.the -period a vapor container inspectica was made. Pipe A
temperature measurements made downstream of the Wessurizer solenoid d'
relief valve indicated possible leakage across the ealve seat was occurring.
The valve was isolated from the safety valve discharge header and w311 be dismantled for inspection at the refueling outage. All other conditions noted in the vapor container were normal.
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 compensate for reactivity lost through burnup.- At the end of the period the plant-was operating at a power level of 160 We and a main coolant average temperature of $07 F.
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During May five Core I-spent assemblies were shipped off site i
for. inspection and examination under an A.E.C. contract.
LO Nine new fuel assemblies were delivered to.the plant in May.
D During unloading one assembly was slightly damaged and was returned to the manufacturer for repair. A total.of 62 new fuel assemblies are now' in storage at the site.
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3 No reactor scrams or plant shutdowns occurred during May.
Maintenance Pollowing is a summary of major activities carried out by plant maintenance personnel during May:
1.
The overcurrent_ trip devices of the h80 volt air circuit breakers were inspected and tested.
2.
Overhaul of No. 2 manipulator crane was completed.
3 Modifications to the in-core instrumentation lift.ing fixture to inprove its handling characteristics continued during the portod.
h.
New fil?.ers were installed in the spent fuel pit cooling and purification system.
5.
A valve tapection of the service air compressor was conducted.
6.
Final modifications to the control rod drive shaft storage rack have been complet.ed.
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7 The shield tank cavity jacking mechanism of the fuel handling system was decontaminated and inspected.
' 8.
No. 2 control air compressor unloader was cleaned and adjusted to clear sticking.
9 Reconditioning of spare primary plant valves continued during the month, f
- 10. No.1 gland steam extractor was inspected.
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- 11. No.1 charging pump rams were replaced with spares and the pump repacked.
Chemist {L Throughout the period main coolant oxygen levels remained below the point of detection.
On May 20 main coolant purification was secured and hydrazine was added to the system. An average NH3 concentration of 8.0 ppm was maintained for the remainder of the period.
Prior to the hydrazine ic activity ranged between h.8 and addition ghe average main coolant spec {pc/mi when 5.h x 10' pc/ml and rose to 7.1 x 10' purification was secured.
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- 31-Main coolant Iodined31 concentration varied between 1.h and 1.5 x' 10-3 pc/ml before purification was secured. ~The I-131/I-133 atomic ratio.was h.6.
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- A-typical main coolant gas analysis made during the period indicated:
Xe - 135 1 7 x 10-1 pc/cc Xe J 133 1 36 pc/cc A - h1 6.7 x 10-1 pc/cc Beginning May 2h a slight increase in main coolant crud was noted.-
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The increase continued until'May 28 when it reached a high of 1,29 ppm. The purification system was returned to arervice and the crud level had dropped to 0 75 ppm at the end of the reporting period. Radiochemical analysis of -
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the crud is now in progress and will be reported in a subsequent operations report.
During the amnonia test, normal hydrogen makeup to the main coolant system was suspended due to internal hydrogen-generation resulting from the decomposition of hydrazine into H2 and Np. The composition of the main ecolant dissolved gas was analyzed as 65% H2 and 35% N2 this being i
i close to the theoretical hydrazine and ammonia decomposition products ratio.-- H2/N ~= 2/1. Since the amount of hydrogen generated was in excess 2
of that required for normal chenistry the surplus was withdrawn to storage in the' waste gas surge drum.
1 Reactor Plant Performance Reactivity changes associated with varying main coolant chemistry 7'
were followed closely.during the period. The core depletion rate was normal until May 9 when, with all rods at the upper program withdrawal limit, an essentially zero core depletion rate was established.
Purification was-
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secured on May 13 and was followed by a slight core reactivity ^ increase.-
Purification was re-established on May 15 and was followed by 'a slight core
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reactivity decrease.
. The addition of hydrazine to the main coolant. resulted in a gradual'
'l reactivity gain of. 0.27%f(O. Following the initial gain core reactivity depletion rate wa's normal and purification was secured. On May 28 the bi-weekly control rod exercise program was performed and purification was established using an anion resin column. Core depletion rate following-these
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changes was' abnormally high for' one day followed by two days of essentially zero d3pletion until returning to~ the expected depletion curve late -in the :
period. Operation with ammonium. hydroxide coolant chemistry resulted'in the i
plant' being able to operate at near rated power for an extra ni:le days.
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Thelfollowing was determined by means of.in-core instrsientation measurements'at~c power level of $h0 !Wt and all rods at the fully withdrawn
, h position ~of 88-7/8 inches:
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q F6 T-2.7 Minimum QDNER = 2 5 a
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-h Turbine Plant Performance To further evaluate the main steam line vibration analysis, instrumentation has been attached to vertical sections of the main steam piping to measure maximum line deflection at the steam generator shell outlets of Nos. 3 and h loops.
Failure to restore the circulating water system discharge siphon was reflected in plant performance data for the month.
Peak electrical output was limited to 168 We as opposed to a normal 170 We.
Increases in plant heat rate and steam flow were accompanied by a corresponding decrease in plant thermal efficiency. Modifications continued to be made to the temporary air removal system in an effort to improve the operating efficiency of the circulating water system.
The results of a recent Feedwater Heater Terminal Difference measurement were:
3 161 We Q l.6" Hg Back Pressure
- 1 Heater 90 F TD
- 2 Heater 13 1/2 F TD
- 3 Heater 60 F TD the data indicates that No. 2 heater continues to operate outside its design range, Representatives of the manufacturers obtained
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performance data on the heater during May.
Calorimetric data taken during the period indicated:
162.2 WEG Q 1.6 " Hg.
Back Pressure - $30.h Wt Health and Safety Liquid waste with a total activity of 0 37 me was discharged x
7 from the plant during May.
Gaseous wastes containing an estimated 200 ne was discharged durine, the same period. At all times the concentration of waste products <'.ischarged from the site was well below the maximum permissible.
Daring May, hh drums and 3 wooden boxes of solid radioactive waste containing a total actiirity of 827 me were prepared. h2 drums of solid radioactive waste containing a total activity of 387 me were shipped from the site during the same period.
Efforts to improve the visibility of the spent fuel pit water commenced during May with the installation of filters in the fuel pit water recirculation line. Radiation levels measured on the filters during interchange measured 1 - 5 r/hr saturated and 2.5 r/hr dry. Drumming of the used filters resulted in levels being reduced to 120 - 175 mr/hr
("'1 centact with drums and 6-lh mr/hr at one meter.
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A radiation survey of primary plant equipment outside the vapor container indicated no significant increase in radiation levels from those of previous surveys.
Five Core I spent assemblies were shipped off site for exami-nation under an A.E.C. contract. Average radiation levels as measured on the cask prior to each shigment were 2 - 5 mr/hr contact.
Contamination levels were < 2000 dpdft Sodium cyanide decontamination of equipment utilized during Core I refueling continued during May. Radiation levels measured on the shield tank cavity jacking mechanisms were reduced from 550 mr/hr were10{/hr.dpm/ft{aximum contaminatiog levels before and after decontamination to 100 and 200,000 dpm/ft respectively. Similar operations with the in-core instrumentation lifting rods saw radiation levels reduced from 125 mr/hr to 12 mr/hr measured at o e inch. Contamination levels before and aftor decontamination were 10 dpm/ft and 2000 dpm/ft2
,r3 respectively.
Personnel exposure for Yankee plant personnel as measured by film badges for the month of April 1963 weret 62 Average for all station personnel
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3h0 r3 Maximum indiT,idual exposure
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V Plant Operations Attached is a summary of plant operation statistics for the month of May 1963, and a plot of daily average plant load for the same period.
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,I IANKEE ATOMIC ELECTRIC COMPANY - OPERATING -
SUMMARY
MAY 1963
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EIECTRICAL MONTH YEAR TO DATE'
. Gross Generation KWH 122,70h,000
$$8,502,800 2,259,97h,800 Sta. Service (While Gen. Incl. Losses)
KWH 7,51h,517 3h,7h2,62h 165,h99,191 Net Generation KWH 115,189,h83 523,760,176 2,09h,h75,609 Station Service 6.12 6.22
. 7.~32 Sta. Service (While Not Gen. Incl. Losses)
KWH 960,791
.Ih,929,629
. Ave. Gen. For Month (7hh HRS.)
KW 16h,92h Ave. Gen. Running (7hh HRS.)
KW 16h,92h-PLANT PERF@.MANCE Net Plant Efficiency 28.88 29.23 Net Plant Heat Rate Btu /KWH 11,818 11,676 h
Ibs. Steam / Net KWH 1h.2h 13.91 Circulating Water Inlet Temp.
Maximum F
$1 Minimum F
h1 Plant Operating Factor 99 29 91.57 68.1h.
NUCIEAR MONTH CORE II TO DATE Times Critical 0
35 297 Hours Critical HRS 7hh-6051.h2 19,298.85 Times Scrammed 0
5 35' Equivalent Reactor Hours @ $h0 FMt HRS 738.7 5528.9 13,hh6.0-1 i
Average Burnup of Core WD/mtU 799.1 g981.0 Control Rod Position'.at Month End Equilibr$um at
$30 FWt, 508 F Tavg.
Group 1 Rods out-inches 88 7/8 Group 2
'88 7/8 Group 3 88 7/8 Group h 88 7/8
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Group 5 88 7/8 Group 6 88 7/8
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