ML19351E211
| ML19351E211 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 07/22/1966 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E210 | List: |
| References | |
| NUDOCS 8011260217 | |
| Download: ML19351E211 (10) | |
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Submitted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts July 22, 1966 semean
This report covers the operation of the Yankee Atomic Electric Com;3any plant at Rowe, Massachusetts, for the month of June 1966.
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The plant was operated at maximum permissible power level through-out the period. Plant load averaged 177.5 We for the month w_th variations between a minimum of 172 We and a maximum of 183 Mie as secondary plant perfornnce followed changes in the inlet temperature of the condenser circulating water.
Operation with boron in the main coolant continued until June 22.
For details of the boron removal, see the Chemistry section of this report.
Ten spent fuel assemblies were shipped to N.F.S. for reprocessing on June 3 The empty ten-element shipping cask was returned to the site on June 20.
Minor damage to the cask had occurred at N.F.S. after the previous shipment had been unloaded and the cask head was being reinstalled. The damage was repaired by Yankee personnel, and the cask was loaded with nine spent fuel elements, all removed from Core IV.
After the co:apletion of heat rate tests on the loaded cask, the shipment left the site for N.F.S. on June 2h. The two shipments made in June are the eighth and ninth in the (3
series of spent fuel shipments, bringing the number of elements shipped in k
the ten-element cask to 89 Total elements shipped to date is 10$.
On June 28, fourteen new fuel elements were received in the first of three shipments from Westinghouse.
The bearing water temperature and cooling demand of No. 2 main coolant pump continued to increase through the reporting period. The c
bearing water temperature w s 1620F at the end of the period.
)
On April 22 an air charge to the vapor container increased the weight of dry air in the vessel to approximately 70,000 pounds, which represents a nominal pressure of 2.2 psi. This pressure was selected in order that the performance of the continuous leakage monitoring system could be evaluated at 10% of the 22 psi test pressure. The leakage rate during the ensuing 60-day period ending in June has been calculated to be 0.011%/ day.
7 By direct extrapolation to the 22 psi test pressure, this value represents y
a leak rate of 0.11%/ day. The maximum allowable leak rate is 0.50%/ day.
On June 29 the monthly control rod exercise program was completed; all rods functioned properly.
A representative of the I.A.E.A. made an unannounced visit to the plant during the period. Operational records were inspected for verification that no unreported plant shutdowns had been made since the last I.A.E.A.
inspection in February 1966.
's There were no plant shutdowns or reactor scrams during the month of June.
The Yankee Atomic Electric Review Committee met at the plant during the period to rev$ew plant operations since their last meeting in December, 1965
Plant Maintenance The following is a list of the major items performed by the plant staff during the month of June,1%6:
1.
Ion exchange capsules were installed or relocated as necessary to satisfy the requirements of boron removal and stretchout operation.
2.
Minor repairs were made on the ten-element spent fuel shipping cask.
3.
Drilled a hole in each of two vapor container outer support columns to allow inspection of the interior surfaces. The holes were threaded and plugged after the inspection revealed the inner metal surfaces to be dry and rust colored, no unusual corrosion or scaling was seen.
h.
Completed the rejuvenation of the No. 2 filter in the water treatment plant with the installation of new anthracite filter material. A similar project was start-ed on the No. 1 filter: the used anthracite was removed and the internal surfaces were cleaned and painted.
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5.
In the water treatment plant, the No. 2 demineralizer resins were replaced.
6.
Replaced the complete shaf t assembly and the guide bearings on No. 2 gravity drain tank transfer pump; one section of the original shaft had sheared. A strainer was installed at the pump suction.
(^'s 7
Twenty three zirculoy pieces, consisting of lh followers, K--
8 shims and one cruciform blank, were shipped to Dresser Products for modification.
8.
Leak tested the the Prototype Fuel Assembly that is on display in the Information Center.
9 Replaced steam trap on turbine first stage-pressure gage line.
10.
All fire protective equipment and systems were checked and/or tested in the presence of the NEPIA Fire Insurance Inspectors.
. Instrumentation and Control The following is a list of major items performed by the plant staff during the month of June, 1966:
1.
Designed and built an electronic device to aid in the identi-fication of coaxial cables when several cables are unmarked in a junction box or cable run.
2.
Assisted a University of Maryland PhD candidate in testing a prototype truck-mounted, portable, underwater gamma spectrometer intended for future use in the environmental waters of nuclear plants.
3 A nitrogen bottle was installed for use as an alternate pressure supply for the opening of the two air operated valves which supply steam to the steam driven boiler feed 7s(j pump during the loss of AC accident condition.
h.
Repaired a leak in the detector tubing of the gravity drain tank bubble-type level transmitter.
5.
Changed the set point of the gravity drain tank high level alarm from 98% to 90% by lowering the alarm switch displacer.
('J The off-site accident-emergency air particulate monitoring 6.
system equipment was moved from the Field Lab to the Furlon house, reinstalled and tested, and equipped with a complete set of emergency spare parts.
Reactor Plan + Performance The reactivity change resulting from the remc7al of boron from
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the main coolant system on June 22 was compensated for by the insertion of x
group A control rods to 66 inches. The rods remained inserted for the balance of the period, being slowly withdrawn as necessary to offset fuel burnup.
Core reactivity depletion during the reporting period was normal at approximately 0 9%AK/K per 1000 WtD/MU. Throughout Core V the plot of boron concentration versus burnup (WtD/MU) indicates a constant boron depletion of 0.156 ppm per WtD/M U.
This value compares with previous values as tabulated below:*
Core I O.163 ppm /WtD/MU Core II
.158 Core III
.162
- from WCAP-2938
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The following parameters were determined by means of in-core instrumentation at $97.8 Nt, 527.0 F Tavg, 79 ppm boron, control rod i
groups B, C & D 0 88 7/8 and group A @ 88 h/8 v
FQ 2.2 F
19 g
Min. DNBR -
3.28 589.5 F Maximum outlet temperature Secondary Plant Performance During the period the condenser terminal difference increased approximately four degrees, and the condenser cleanliness factor dropped from 66% to 58%.
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The terminal difference of No. 2 feedwater heater incre ised by appro:rtimately two degrees, indicating possible tube leakage. Steps taken to minimize the effects of the leakage resulted in the recovery of one degree on the terminal difference.
Chemistry At the start of the report period the coolant boron concentra-
/
tion was 158 ppm. On June 22, after the boron level had reached 71 ppm w/
through normal core burnup, the boron dilution operation was initiated.
The main coolant boron concentration was reduced to 18 ppm by the addition of 25,000 gallons of aerated, demineralized water. Following the coolant dilution operation, the boron level was reduced to 0.5 ppm by purification through the No. 3 anion demineralizer. During the dilution and anion purification periods, coolant ammonia concentration increased to 0.39 ppm due to the Mdition of aerated water and the absence
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of cationic purification.
Purification through the mixed bed (H+, OH-)
No. 3 demineralizer commenced on June 2h and the ammonia level was reduced to a negligible value three days later.
A repeat test of pressurizer vapor space conditions was com-pleted. The purpose of this duplicate tes. was to substantiate the results that were reported in the last period. This test data is in good agreement with the previous data. The dissolved oxygen content of the pressurizer drain water could not be verified due to a malfunction of the MOV-513 bleed line sample valve. A comparison of the test results is as follows:
l TEST 1 TET 2 cc cas ce gas Condition IIGr cond 02 N2 H2 liter cond 02 N2 H2
'~s 2 wk no vent j 1380 0.06 18.3 81.0 1h60 0.07 13.h 86.5 1665 0.06 18.3 81.0 lh60 0.07 11.9 88.0 h wk no vent
+
After 1 wk vent 313 0.h0 27 0 72.6 28h 0 50 28 5 71.0
- Dissolved 02 in pressurizer drain water was 3 - $ ppm during Test 1; no sample for repeat test.
The pressurizer capillary vent system was closed on June 21 so the effects of major dilution with aerated water could be evaluated. The vessel vapor space was sampled en June 28 and the data was comparable to p' evious r
data collected af ter a no vent condition. The capillary vent was reopened and furtner sampling will b3 performed to collect data af ter a period of f ';
venting.
J Main coolant dissolved oxygen levels were below the detection limit (less than 5 ppb). The system crud level varied between 0.08 ppm and 0.15 ppm, and the average tritium concentration prior to the boron dilution operation was 2.h uc/ml.
Primary to secondary leakage in the No. 3 steam generator remained unchanged at h - 6 gallons per day.
(s The resins in the No. 2 water treatment demineralizer were re-( )
placed. This was the first resin recharge since plant startup; the unit had processed more than lh million gallons of water from Sherman Pond.
Following the
.ain coolant iodine-131 level increased from 3.,8 x 10'goron dilution, the uc/ml to 9.8 x 10 uc/ml, possibly as a result of the insertion of group A control rods and corresponding core power re-distribution.
7V A comparison of crud samples from the new upstream and t he down-stream bleed line sample points is as follows:
dpm/mg crud Upstream Downstream Upstream Downstream 6
0 Mn-$h 3.1 x 10 2.7 x 10 Fe-$9 2.0 x 106 6
2.9 x 10 Cr-$1 1.9 x 106 2.7 x 106 Co-58 1.5 x 107 1.0 x 107 Rf-181 5.8 r 10$
3.5 x 105 Co-60 5.h x 106 3,1 x 106 Main coolant gas samples collected before and after the boron dilution had the follcwing analysis: uc/cc gas Before Dilutir After Dilution A-kl 9.0 x 10^3 1.2 Ie-133 6.3 x 10-2 9.$ x 10-2 Xe-13$
7.0 x 10-2 8.7 x 10-2
. Health and Safety Fif ty-five drums of radioactive waste were shipped during the period. The total activity contained in the shipment was h93 me.
Two shipments of spent fuel were made during the period: the first with 10 assemblies and a total activity of 0.99 megacuries, the second with 9 assemblies and a total activity of 6.09 magacuries. The gamma radiation levels from the cask on contact and at one meter, for both shipments, were generally <1 mr/hr and <0.1 mr/hr, respectively, with maximums of h.$ mr/hr and 0.2 mr/hr. The second shipment showed detectable neutron radiation levels of 0 3 mrad /hr fast and 0.00h mrad /hr slow at one meter from the cask. Non-fixed on the cask for both shipments were<1 x 10 gurface contamination levels curies /100 cm2 beta-gamma with no detectable alpha activi ty.-
During June the waste disposal liquid releases totaled 98,590
(' i gallons containing 67 uc of gross beta-gamma activity and 179.h0 curies of tritium. Gaseous waste releases during the same period totaled h3$ me of gross beta-gamma activity.
In addition to the above liquid waste releases a total of 163,228 gallons of water were discharged from the secondary plant. The total gross beta-gamma and tritium activities released from the secondary plant were 7 uc and 1.02 curies, respectively.
)
The clapper, which was removed from No.1 main coolant loop check valve during the April h-8 shutdown, was decontaminated during the period using the chemicals and techniques which are intended for use in the decontamination of main coolant loops and other items of primary equipment. The radiation levels of the clapper were reduced by at least a factor of twenty. After the chemical decentamination, hand scrubbing of the piece resulted in a further halving of the radiation n
levels with the remaining activity apparenth tied up in crud which was
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trapped under the nut assembly.
Radiation exposure doses for Yankee plant personnel, as measured by filJn badge, for the month of June,1966 were Average accumulated exposure dose h7 mrem.
Maximum accumulated exposure dose 229 mrem.
Design Changes
- 1. Started replacement of carbon steel piping between discharge of water treatment plant acid pumps and the acid mixing chamber. This section of carbon steel piping is being replaced with polyvinyl chlorido piping to 12nprove the service conditions of same.
Operations Attached is a summary of plant operating statistics and a plot of daily average load for the month of June,1966.
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YANKEE ATOMIC EIETRIC COMPANY -- OPERATING
SUMMARY
EIETRICAL
}0 NTH YFAR TO DATE Gross Generation WH 127,765,h00 775,53h,900 5,766,375,800 Sta. Service (While Gen. Incl. Losses)
WH 7,889,696 h6,51h,122 392,926,616 Net Generation WH 119,875,70h 729,020,778
$,373,hh9,18h Station Service 5
6.18 6.00 6.81 Sta. Service (While Not Gen. Incl. Iosses)
WH 0
216,250 22,h57,828 Ave. Gen. For Month W
177,h52 Ave. Gen. Running W
177,h52 PIANT PERFORMANCE Net Plant. Efficiency 27.89 28.82 28.h9 Net Plant Heat Rate Bru/WH 12,236 11,8h2 11,979 Plant Operating Factor 99.h9 97 07 70.98 4
Reactor Plant Availability 5
100.00 98.01 82.06 NUCLEAR forfH.
CORE V TOTAL Ecurs Critical HRS 7J0 5h80.10 bl,hhl.06 Times Scrammed 0
1
$0 Burnup Core Average ND/MTU 863.63 6387.63 Region Average ND/MrU A (INNER) 883.77 6217 63 21,759.hh B (MIDDLE) 977.12 7219.63 13,978.73 c (OUTIR) 738.07 5h89.20 5,h89 20 ZIRCAIOY TEST ASSEMBLIES 1179.61 8953.h2 8, %3.h2
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