ML19351E025
| ML19351E025 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 07/23/1965 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| References | |
| NUDOCS 8011250457 | |
| Download: ML19351E025 (11) | |
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YANKEE NUCIZAR KMER STATION OPHIATION REPORT NO. 61:
For the month of JUNE 1965 O
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O Submitted by YANKEE AT0!EC ELECTRIC COMPANY Boston Massachusetts l
July 23, 1965 l
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This report covers the operation of the Yankee Atomic Electric fi Company plant at Rowe, Massachusetts for the month of June, 1965.
At the beginning of the reporting period the plant was operating at a power level of 137.7 M4e.
"St retch-out a conditions existed through-out the period with reactor power and average temperature decreasing to compensate for burnup as all control rods were essentially in the full out position.
In addition, the main coolant system was being operated in a high pH condition to take advantage of the increased core reactivity condition.
On June 1, a chemistry crud test was begun in an attempt to further define the main coolant crud behavior and its associated effects upon core reactivity. This test consisted of opening the loop bypass valves and observing crud behavior. At the conclusion of this test, a second chemistry test consisting of ammonia removal and return was performed. The ammonia was reinjected on June 30. The complete test procedure and chemistry results appear in the Chemistry section of this
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report.
Refurbishing and fitting out of the 10 element spent fuel shipping cask continued until June 21, when the cask was placed in the spent fuel pit for underwater loading.
Prior to placing the cask in the pit, the internal fuel basket was filled with demineralized water and 8
small bubbles were observed streaming out from under some of the fastening screws.
Various tests and analyses by both personnel from the plant and the cask supplier were conducted with the conclusion that no serious corrosion problem exists within the basket components.
While attempting to load the cask, unlatching problems developed with the spent fuel pit manipulator crane grappling tool. The cask was
,r' s loaded using the plant designed handling tool suspended from the yard s_J area crane through an open spent fuel pit hatch cover.
When time permits, the tool boom from the manipulator crane will be removed and the cause of the trouble corrected.
Subeequent to loading, the cask was removed from the pit and placed upon the decontamination pad. Decontamination and various tests were performed before the cask was laid down upon its special railroad car. An attempt was made to measure the heat buildup in this, the hottest shipment in the present batch but due to relatively low heat levels and variations in ambient temperature, results were rather inconclusive.
OnJune26,thecirculatingFtoambient. pumps were started and quickly reduced the temperature from about 119 The pumps were shutdown on June 27. At the end of the reporting period the temperature had risen to about lO50F.
On June 2, three members of the I.A.E.A. installed two seals
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on bolts which secura the missile shield over the reactor head to the charging floor. They are scheduled to return at the start of refueling
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to witness the seals removal. The purpose of these seals is to prevent j
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removal of nuclear fuel without their knowledge.
The plant received the following new reactor components from various suppliers in preparation for refueling.
Eighteen new, h.9h%
enriched, stainless steel clad, fuel assemblies; two stainless clad Ag-In-Cd control rods; and twenty-two zircaloy control rod followers.
Fluctuations in circulating water inlet temperature caused changes in secondary plant performance, which in turn, affected plant load throughout the month.
The load at the end of the month was 129 Ne.
This power level was higher than expected if one assumes the previously measured coastdown burnup rate of M 2/3 We per day.
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No plant shutdowns or reactor scrams occurred during June.
%j Plant Maintenance Following is a summary of major activities carried out by the plant maintenance staff during June:
1.
Completed the internal decontamination program on reclaimed 0
ion exchange capsules and filled one capsule with mixed bed resin and placed it in storage.
2.
Rewired the new fuel vault hoist motor for speed reduction.
3 Repaired the test valve at the low pressure surge tank gas sample point.
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Completed assembly of twenty-four drive shaft weight tubes
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to be used during refueling to expedite the removal and installation of drive shafts.
5.
Recabled the main hook of the yard area crane under the supervision of the vendor to insure that the 10 element spent fuel cask can be handled safely.
6.
Lapped two valves in No. 1 charging pu.*p.
7 Inspected the No.1 waste gas compressor.
8.
Inspected and repaired the control circuits of the No. 1 control air compressor.
Chemistry During a previous shutdown, radiation levels on main coolant
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bypass lines were found to be not much higher than the main coolant lines v
themselves.
(Refer to Operation Report No. 51, March 1965). This raised
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the possibility that the bypass lines were not trapping crud during high pH operation as they were found to be doing during unadjusted operation.
i(j To prove or disprove this possibility, on June 1, the four main coolant bypass valves were opened sequentially at half hour intervals starting at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />. These valves remained open until 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br /> on June 3, when they were all closed.
The effects of this were followed by continuous recording of the bleed line radiation level, crud samples, and routinely recorded plant parameters.
The bleed line radiation level changed from a steady-state level of 18 mr/hr to a maximum level of 205 mr/hr, which occurred 11/2 hours after the last valve was opened. The radiation level then decreased gradually throughout the remainder of the test period as crud level decreased with a system half removed rate of 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br />. The opening of each valve caused an increase in the radiation level with loop 3 having the most pronounced effect.
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Crud level went from 0.79 ppm before the valves were opened to 73. ppm after the valves were opened. On June 3, when the valves were closed, the level had decreased to 15. ppm.
Twa significant conclusions can be drawn on the bypass valve opening test as follows:
0 1.
That previous radioactivity measurements on the bypass lines were in error and that the radioactivity and crud drop out in the bypass lines is similar whether the coolant chemistry is high or low pH.
2.
The rate of drop out of crud from the main coolant system (system half removal rate) is the same whether or not the bypass valves are closed. This indicates that some
(~N mechanism, or equipment, much stronger than the bypass K/
lines is acting to remove crud.
A second chemistry test began by stopping the feed of ammonia to the system. On June 3, after the bypass valves were closed, the purification system was started with flow through a mixed bed capsule to remove the remaining ammonia. The ion exchanger remained in service until June 30 (except for a period on the 6th through the 8th when a leaking standpipe on the purification downstream filter was repairedL During this period of unadjusted pH operation with H+ and OH-system purification, the nominal crud level averaged 0.6h+.08 ppm.
This corresponds to a system release rate equivalent to 670 mg/dm2/ month.
A control rod exercise on the third of the month and another on the 2hth resulted in crud level increase to about 20 ppm.
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The purification system was secured and ammonia was injected to
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the main coolant system on June 30, marking the end of this chemistry test.
Intentions are to run without purification and at high pH for about three weeks.
The main coolant oxygen concentration was below detection.
-h-A typical main coolant crud analysis performed on 6/7/65
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indicated:
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dpm/mg crud 5.2x10[6 Cr - $1 1.1 x 10 Mn - 5h h.7 x 10 Fe - 59 Co - 58
.:,.5xloj Co - 60
$.1 x 10, D
' x 10 Hf - 181 In - ll6m n 's detected A typical main coolant gas analysis performed on 6/28/65 indicated:
Xe - 133 2.8 x 10~ pc/cc of gas Xe - 135 1.7 x 10-2 pc/cc of gas A - hl 7.6 x 10- pc/cc of gas q
v Reactor Plant Performance The results of a four wire flux wire irradiation were:
hh2 Wt h83 F T avg.
all rods @ 90 3/8" 8
2.5 F
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q F
2+1 6H h.9 q"
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$360F Max. outlet temp.
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The opening of the bypass valves caused about a h.7 W t drop in reactor power. This power was regained when the valves were closed and is believed the reactivity effect was caused by core bypass flow.
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The ammonia removal was followed by the expected reactivity los:.. The magnitude of the loss wns about 15 Wt, which was less than that experienced in the past. A control rod exercise was performed and the filter was taken out of service to repair a leak in this period which may have terninated the transient. While the purification system was out of service, a gain was observed in reactivity, but the ammonia concentration e.lso was noticed to be on the increase. After the purification system was again put in service, a high crud reading was noticed, followed by a corresponding reactivity loss, followed by a "flht spot", a 5-day period of no burnup. After the control rod exercise of June 2h, another high crud reading was observed followed again by a corresponding reactivity loss and " flat spot".
The overall result of the two flat spots was that the reactivity condition of the reactor was about. 25C 6 K/K higher than would be expected for low pH water chemistry. The exact cause of this phenomena is unknown, but it was observed to occur during Core I at this same m
approximate power level and neutral pH.
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5-After the ammonia was returned to the system on June 30, the core regained about.20% 6 K/K to return the expected high pH point.
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l Turbine Plant Performance Terminal difference data taken on June 25 gave the following results:
Number one heater 11.ho Number two heater 12.60 Number three heater 11.00 Instrumentation and Control Following is a summary of major activities carried out by the plant Instrumentation and Control group during June:
1.
Assembled and tested a new vapor container penetration.
V 2.
Repaired the amplifier from No. h main coolant bearing temperature indicator.
3 Repaired several intra-plant page phone amplifiers.
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Repaired several radiation survey meters.
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- 5. Worked on refueling instrumentation power supply panels.
6.
calibrated No. 1 nozzle steam pressure transmitter and main control board indicator.
7 Assembled a test stand for maintenance of some primary plant amplifiers.
8.
Made several repairs to the water treatment pH measuring (g
system.
9 Repaired the vapor container relative humidity indicator.
10.
Repaired a dosimeter charger.
- 11. Worked on setting up a noise analyzer for electrical measurements.
Health and Safe g deing the month of June 1965 the following solid radioactive wastes were prepared and shipped off site for disposals a.
ninety drums containing a total activity of h90 me.
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four casks ($ tons) containing one drum of resins and
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three filter drums, with a total activity of 2.606 curies.
- 27,760 gallons of liquid containing a gross beta-gamma activity of 0.0h me and 57.87 curies of tritium were discharged during June.
Gaseous waste containing a total activity of 19 0 me was discharged during the same period.
Nine of the new Core V fuel assemblies (1st shipment) were examined.
No surface contamination was detected. Radiation levels along the tubes were 2-3 mr/hr at 1 inch.
Samples of air drawn from between the assembly tubes indicated no airborne radioactivity present.
Four of the six remaining reclaimed ion exchange capsules have been internally decontaminated with ammoniated citric acid. Radiation levels of these four capsules before and after decontamination are presented here. The left hand numbers represent present radiation levels.
The numbers to the right in parentheses represent radiation levels prior to decontamination.
Radiation Ievels at 1" (mr/hr)
(j Location on Capsule
- 22
- 12
- 15
- 16 Top h5 (h00) 10 (150) 100 (150) 70 (200)
Top Horizontal Weld 150 (500) 10 (175) 100 (250) 90 (250)
Supporting " Ears" 50 (1200) 15 (150) 90 (150) 80 (350)
Screen Level 2500 (10,000) 300 (1200) 200 (1500) 250 (5000)
Bottom 750 (10,000) 50 (7000) 300 (3500) 800 (7500)
Capsule No. 7 with radiation levels of 35-110 mr/hr from top to bottom did not warrant attempts at further reduction. The last capsule (No. 5) with a maximum radiation level of approximately 35 r/hr at one inch was deemed to hot to handla and was put in storage on site in a concrete brick cave pending further disposition.
Recalibrated seven portable sum ey instruments.
Commenced leasage and calibration tests of all personnel dosimeters.
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s Radiation levels contact with the loaded 10 element spent fuel cask were:
0.h-0.7 mr/hr gamma,1-2 mrad /hr fast neutrons, and 0.1-0.2 mrad /hr slow neutrons. Contamination levels prior to decontamination ranged generally from 1100-9200 dpm/100 cm2 beta-gamma, with a maximum of 16,000 dpm/100 cm2 beta-gamma. One washing reduced these levels to 300-1000 dpW100 cm2 beta-gamma with a maximum of 3000 dpm/100 cm2 beta-gamma.
No alpha contamination was detected.
Two large, empty resin shipping casks and the empty control rod shipping cask have been placed'on a railroad flatcar and put on the spur track leading to the turbine hall. The radiation and contamination levels of the three casks are below those specified for the clean area.
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. Cx In compliance with a request from U. S. Public Health Service,
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Division of Radiological Health, for a tritium study, samples of plant
'v' liquida, waste gas, vapor container atmosphere, and environmental liquids were collected for analysis by their Northeastern Radiological Health Laboratory.
The following item was inadvertently lef t out of the May Operation Report. During a routine blowdown of the low pressure surge tank cover gas to the waste disposal system on May h, a severed a/8!'
test connection was discovered in the vent line. This allowed some of the gas to escape in the LPST cubicle. The released gas was exhausted through the ventilating duct in the LPST cubicle to the 15,000 cfm ventilating fan, and thence out the primary vent stack without alarming the stack monitor. Assuming the break'; occurred at the start of the operation,16 cubic feet of gas containing a calculated h3 me of A-hl, Ie-133 and Ie-135 plus an estimated h.5 zoc of tritium were released during the four minutes gas was leaking. The gross gaseous concentration g
at the release point of the stack was 2.83 x 10-5 pc/ce.
V The concentration was repaired and reinforced to prevent a similar occurrence.
Personnel exposure for Yankee plant personnel as measured by film badge for the month of June 1965 were:
S Average for all station personnel 106 mr
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Mari nnun individual exposure 500 mr
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Plant Operations Attached is a summary of plant operation statistics for the month of June 1%$ and a plot of daily average load for the same period.
The following Operating Instruction was issued during the month:
50hH - Operating Instruction - Purification System i
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YANKEE ATOMIC ELECTRIC COMPANY -- OPERATING SUIEARY JUNE 196$
ELECTRICAL MONTH YEAR TO DATE Gross Generation KWH 92,h23,000 717,129,600 h,680,2h5,800 Sta. Service (While Gen. Incl. Losses)
WH 6,603,600 h5,0$h,h80 32h,716,589 Net Generation WH 85,819,h00 672,075,120 h,355,529,211 Station Service 7.lh 6.28 6.9h Sta. Service (While Not Gen. Incl. Iosses)
WH 0
l$5,936 19,95h,387 Ave. Gen. For Month (720 HRS)
KW 128,365 Ave. Gen.
Running (720 dRS)
KW 128,365 PIANT PERFORMANCE Net Plant Efficiency 27.13 28.37 Net Plant Heat Rate Btu /WH 12,579 12,029 Lbs. Steam / Net KWH 1h.55 lb.09
-m Circulating Water Inlet Temp.
Maximum F
65 Minimum F
h2 Plant Operating Factor 73 21 90.92 71.79 Reactor Plant Availability 100 99.69 83.60 MONTH Code IV TO DATE NUCLEAR Times Critical 0
20 3h5 Hours Critical HRS 720 7,158.62 3L,959.31 Times Scramned 0
5 h9 Equivalent Reactor Hours @ 600 Wt, HRS 527.12 6,oo8.82 25,h97.52 Average Burnup of Core WD/mtU Control Rod Position at Month Ehd Equilibrium at h20 m t 0 h78 F T avg.
REDION
- MONTH TOTAL BUrGUP Group A Rods out-inches 90 3/8 Group B 90 3/8 INNER o73.1 17,297.18 Group C 90 3/8 MIDDLE 756.9 lb,631.bh Group D 90 3/8 OUTER 509.7 6,137.h9 E6
$96.7 29,h23.81 Boron
< 1 ppm
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t YANKEE ATOMIC EI.ECTRIC COMPANY DAILY AVERAGE LOAD for JUNE 1%$
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' CORE IV REDION IOCATIONS
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