ML19351E224
| ML19351E224 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 03/23/1966 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19351E223 | List: |
| References | |
| NUDOCS 8011260230 | |
| Download: ML19351E224 (12) | |
Text
,
g
...A rp ce,m m
' 50g020 06 50 -A T E
p._ q 2110 co Q
00 YANKEE NUCLEAR F0sDt STATION OPERATION REPORT _ r.i, 62 For the month of FEBRUA,RY,196,6
,i
<p O
11 I,
MAR 3s e
g uj* 1966=
S}
eg:ns:,;,j%
R x
\\
O0 O
Submitted by YANKEE ATOMIC EIETRIC COMPANY Boston Massachusetts Mareh 23,1966 W
s
't U44
_3 ggg gggSo %
4 This report covers the oneration of the Yankee Atomic Electric d ['d Company plant at Rowe, Massachuset'ts for the month of February,1966. At O
the start of the period the plant was base loaded at 185 We.
A test l program was set up in an attempt to.' define the mechanisms involved in core reactivity changes associated with main coolant pH changes.
The test was to consist of two basic runs, both load reductions at h We/ min.
to 30 We and return at h We/ min. to the starting point of 185 We. The first run was to be made. with high-main coolant pH and the second run at low pH. -During these power dips,. primary plant data was to be fed-to a Westinghouse-supplied computer for analysis and reduction to magnetic tapes for further analysis.
On February 1,' after securing the purification system, main coolant pH was raised by the addition of ammonia as NH 0H.
h Prevu4.s pH caanges ~of this magnitude have resulted in core reactivity gains which c re quite consistent both as to rate and total amount.
This time, however, the gain was -developing much more slowly when an un-related scram occurred complicating the test and its analysis.
The reactor scram, the first since October 196h, occurred on February h when a false high level signal was fed inu the reactor protection system as an operator was recalibrating a power level channel. Normal;y, two coincident high level signals are required for scram, but one signil was being' fed to the computer at the time.and was not available, so ti, circuit (Gn was being. operated in the " single" mode.
GQ After determining that-no abnormal conditions existed, the reactor was brought critical'in 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> utilizing a 1/M plot.
One hour later the generator was phased and load raised to 150 We, It was decided to. temporarily postpone the test program until normal plant conditions returned. After a pause at -150 We, for preventive maintenance and lubrication of variona secondary system pumps, the load was raised to first 170 We, then full load by the end of the day.
On February 8, four days after the scram, and eight days after the ammonia injection, a_ reactivity gain began which was typical,as to rate and amount, of previous gains brought about by increased pH.
The high pH load swing portion of the test progran was performed on the 21st, thereafter the ammonia was removed, the expected reactivity loss took place, conditions were allowed to stabilize, and the low pH load swing portion of the test was performed on the 2hth. Further details are given in the~ Reactor Performance section of this report.
The empty 10-element spent fuel shipping cask car arr1 ed back on 3
site. The two jacking and upending yokes, which are about 20 in in cross section, were fractured. It was found that these yokes were acting as the first restraint to any lateral motion of the cask while within its crash A) frame although not intended for this duty. The cask was carefully removed
(
from its railroad car and placed upon the decontamination pad. A close s
examination could detect no damage to the cask. The damaged yckes were s
q c'
removed and new yokes are being fabricated. Spent fuel shipments are being e'
delayed until repairs can be made to the yokes. These repairs are expected to be completed early next month. It is expectsd that some type of spacers will be installed between the cask and the false top to allow the crash frame to absorb lateral loads and prevent restraint by the yokes.
The loaded control rod shipping cask was removed from the spent luel pit, decontaminated, and placed within its crash frame on a railroad flat car to await shipnent by a waste disposal contractor.
Increasing radiat$ sn levels within the spent fuel pit heat ex-changer have dictated its r.noval from service and decontamination. The entire process was completed in two days and is decribed in the Health and Safety section of this report.
On February 3, operators reported that the pressurizer steam bubble seemed to be getting "hard", in that pressure changed more than
,s( ',
normally during main coolant charging operations. This action has been noted previously 'and has been attributed to the buildup of non-condensable gaser in the steam phase of the pressurizer. The pressurizer vent had previou<ay been closed when it was noticed that the high set safety valve was leaking and that the teyerature of the safety valve line had increased (Operation Report No. 61, January 1966).
In view of this situation the right hand capillary vent was again put in operation. A sample takea at i, hat time from the' vent line did not indicate any appreciable increase in gas concentration 9 $
over a' sample taken on February 1, hcwever, several hours later, the pres-surizer out the remainder of the period.
An IAFA inspector made an unannounced visit to the site and entered the vapor container to change a seal the IAFA had placed over the reactor vessel head at the end of the last refueling pe-iod. The purpose of this seal is to insure that the vessel head has not been removed and nuclear fuel 7
diverted without IAEA knewledge.
The gravity drain tank was removed from service and cleaned.
Bacteria and slime had built a heavy layer on the walls and sludge had collected in the bottom of the tank. The tank was drained and the walls were washed with a water jet. After filling the tank the flotsom was scooped off the surface of the water and placed in open top 55 gal, drums. A slurry pump was used to remove the sludge frcm the bottom of the tank and through a shielded filter unit.
An air jet was used to keep the slurry in suspension until most of the ma rial was captured by the filter. Further details are mentioned in the Heanh and Safety section of this report.
Plant S_hutdowns Shutdown No. 81 2 2-h-66 A 3.12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> shutdown resulting from a reactor scram.
Scram No. go 1 2-h-66 An automatic reactor scram from a power level of approximatsty 600 N t c
( ')
resulting from a combinstion of operator calibration eation and a condition of single r.hannel scram.
i
e.
Plant Maintenance 1.
A leak was repaired in the #2 main steam pressura sensing line.
2.
Changed oil in boiler feed, heater drains, and condensate pumps, and added packing to the No.1 and No. 2 boiler feed pumps following recovery from the scram.
3.
Inspected shaft sleeves and totally repacked both component cooling water pumps.
h.
Renewed carbon rings, carbon bull ring, and cylinder liner in No. 2 instrument air compressor.
5.
Filled a reclaimed ion exchange capsule with mixed bed resins and installed it in No. 1 position.
,,( )
6.
A permanent servwe air line was run to the wall pass-through panel in the machine shop.
7.
The strong acid control valve in the water treatment room was replaced.
8.
A crankcase breather was fabricated for trial on one waste gas compressor in an effort to stop oil buildup on the outside of the compressor.
OO 9.
Renewed the carbon ring packing in the No.1 charging pump.
10.
Repaired several steam leaks in the control room heater coil,
- 11. Worked on modifications to the underwater lighting in the spent fuel pit.
c 12.
The No. 1 gravity drain tank transfer pump has been overhauled and returned to service.
- 13. The hoisting cables on the yard area crane were lubricated.
Ih. The steam generator level system pressure sensing lines were heat traced.
Chemistry Main coolant oxygen levels throughout the period were less than 0.0$ ppm with unadjusted pH operation and less than 0.00$ ppm with adjusted pH operation; these values are the detection limits for the respective chem-istries.
The main coolant system was ammoniated to 12 ppm NH 3 by the addition m
of NHh0H on 2-1-66.
The crud level prior to the injection was 0.1h ppm.
i
(
This level steadily increased to 0.h2 ppm after ammoniation. The control rods were exercised'on 2-3-66 and a further increase in crud level to 19 ppm was measured. The crud level increased to $3 ppm following the scram. The
5
-h-purification system was returned to service and the cation cycle in the No.2 mixed bed demineralizer was ammoniated. After 2h hours, the system crud level
~
had been reduced to 2.5 ppm. Recent crud conditions for various plant condi-tions are given here for comparison.
(Isotopic values are dpm/mg).
After Control Pre-test Rod Exercise Before Scram After Scram Condition Un-adjus_ted Un-adjusted 5mmoniated Ammoniated Date 1-26-66 1-26-66 2-3-66 2-h-66 ppm crud 0.12 1 50 0.h2 h3 6
6 ni-5h 9.8 x 105 1.3 x 10 1,3 x 10 2 3 x 106 6
1,9 x 106 h.1 x 106 Cr-51 1.9 x 106 1 7 x 10 Hf-181 2.5 x 105 2.3 x 105 3.6 x 105 8.3 x 105 6
6 Fe-59 1 7 x 106 1.9 x 10 1,9 x 10 2.7 x 106 Co-58 2.9 x 106 3,h x lo6 h,1 x 106 6.1 x 106 Co-60 1.3 x 10 1,g x 106 1.8 x 106 2.h x 106 6
m(j Co-58/co-60 2.25 2.28 2.26 2 55 The following are typical main coolant conditions existing about Feb.10:
Crud 0.o6 ppm boron 662 ppm pH 7.1 Cl-
< 0.05 ppm Cond
>33 pmhos 02
< 0.005 ppm gross act. 9.3 x 10-2 pc/ml NH3 1h.h ppm A main coolant gas analysis was as follows:
Isotope _
pc/cc gas 1
A-bl 2.0 x 10 2 Xe-135 1.1 x 30-(')
Ie-133 1 7 x 10-3 L/
Pressurizer gas phase samples taken through the two capillary vents were analyzed with the following results:
Right Capillary - flow rate of $h lbs/hr gas concentration of 131 ce gas /Kg condensate Lef t Capillary - flow rate of 29 lbs/hr 0
0.1%
2-N2 - 26.h%
H2 - 72.0%
A pressurizer liquid phase sample taken through the drain line was analyzed with the following results:
pH 6.8 boron 836 ppm 3
7.6 ppm es Cond
>33 pmhos NH 7-gross act. 3.9 x 10-2 ye/mi The iodine 131 specific activity after the reactor scram was 2.3 x 10-5 c/ml and the I-131/I-133 atomte ratio was 0 70, which does not p
represent any significant change from pre-scram figures.
y I
Ammonia removal commenced on February 21 by placing the #1
'?
(H+, OH~ cycle) domineralizer in service. The anion cycle was borated and J
the ammonia concentration of the main coolant was reduced below 0.0v ppm on February 2h and remained below this level for the remainder of the period.
Reactor Plcnt Performnce A series of reactor plant tests designed to help define the mech-anisms ' involved 'in core reactivity changes associated vnh main coolant pH changes were startedduring this reporting period. The~ preliminary work began on February 1,' when the' main' coolant pH was increased. A slower and more delayed than normal ~ reactivity gain was realized and crud levels were noted as' lower than in past tests. It was decidad to increase crud to a more normal ~value by c control rod exercise. This action initiated a slow and unexpected reactivity loss and unfortunately at Gis point a non-related reactor scram occurred. After the reactor scram and following the resump-p tion of power generation, all indications of reactivity change were gone and the reactivity of the reactor was on the normal low pH burnup curve.
C)
The burnup rats continued on this curve until February 8, when domineralized water was added to the main coolant syste'n to dilute the boron concentration.
After this, and probably non-related a reactivity gain began and continue" as in many times in the past until the expected 0.7% gain had taken place.
The reason for the delay in the reactivity gain is not understood, but the major variables were crud and power.
(See Chemistry). Further tests are planned for this aspect of the mechanism.
pm
'I _'
After the reactivity gain had taken place and a normal depletion rate was established, a test was performed to attempt to measure the power defect from full power to low power.
Incremental rod worths were summed as control rods were run 'in while turbine-generator load was reduced as fast as practical (about h We/ min.) to about 30 We and then picked up again to full load.
The output of an ion chamber fed to a computer system served as the main source of data.
Immediately after completion of this load dip, the ammonia was removed from the system and the normal reactivity loss commenced.
(
i s
After stabilization, the power dip was repeated with the system at neutral pH.
Boron concentrations were varied so that both power dips were started from approximately the same conditions.
Preliminary results as analyzed by Westinghouse show that more rod motion was required at low pH, which would indicate that more reactivity was required for full power at low pH than at high pH.
Present the y indic'tes that this difference in reactivity, is probably associated with Doppler or fuel temperature coefficient and that boiling voids and poison effects are not involved.
Further tests will be performed in an attempt to further define the findings of this series of tests.
The analysis of a flux wire run made during the period is as follows:
185.8 We 598.5 WT 527.0 F Tavg Rod group A 0 50 5/8", Groups B, C, D @ 87 3/8"
- 'p Fa g = 2.01 (J
Fo
= 2.08 q" DNBR= 3.16 Max. temperature outlet of hot channel 592.00F.
C,
. ~" o Turbine Plant Performance, Feedwater heater terminal difference measurements during the period were:
- 1 95F
- 2 12.0 F
- 3 ll.60F Turbine load 185.5 We Condenser cleanliness factor for the month: 82% (185 We)
Instrumentation and_ Control The following is a list of the major items performed by the plant Instrumentation and Control staff during the month of February:
[
1.
Recalibrated the nuclear recorder on the main control board.
2 Calibrated a test thermo:,ouple to be used in the determination of feedwater heater terminal difference.
3 Recalibrated all instruments (gauges and transmitters) in the water treatment plant.
h.
Recalibrated the condensate pump discharge pressure gauges.
OO 5.
Repaired two dosimeter chargers from the gate house and sev-eral portable survey meters.
6.
Fabricated an insulated eyebolt and installed it on a new spare BF3 neutron detector.
q 7.
Flushed the vapor container drain tank level transmitter and V
connecting pipe.
8.
Repaired the law pressure surge tank pressure indicator on the main control board.
9 Repaired the high voltage supply for the incore instrumentation (flux wire) system.
Health and Safety During the month of February 1966, 55 drums of radioactive waste containing a total activity of 16h.h me were shipped off site for disposal, h9 of these drums were routine vaste containing lh7 5 me and six drums con-taining 17 me, were the solidified potassium permanganate solution used in the fuel pit heat exchanger decontamination.
Liquid waste disposal releases totaling 69,26h gallons containing m
y a gross beta-gamma activity of 0.23 me and 158.29 curies of tritium, were discharged during the month of February. Gaseous waste released contained a total gross beta-gamma activity of 71.8h me.
Correction to Oyegtlen Report No. 61 (January 1966)
Gaseous waste released during January 1%6 contained a totai gross beta-gamma activity of 260.1h me.
In addition to the above February releases, 253,000 gallons of water containing 2.25 curies of tritium were released from the secordary plant.
The gross beta-gamma activity of this water was <9.60 Jic.
The snent fuel pit heat exchanger was taken out of service and de-contaminated. A used and slightly damaged ion exchange capsule was modified and used as a tank to hold the decontamination solutions and a pump and temporary piping was provided to circulate these solutions.
The first solution,10% by weight NaOH and 5% by weight KMnog, was heated with a steam lance and circulated for 30 minutes. This solutien was g
drained and the exchanger was flushed with demineralized water and dried by i
blowing air through !t.
The secend solution, 5% by we: ght citric acid and O.5% by weight versene (Tetra soaium ethylene diamine tetra acetate) was also circulated for 30 minutes. Repeated rinses of the heat exchanger insured that no solution remained in the system. The first solution was drummed rather than passing it through the waste disposal plant, while the second solution and subsequent rinsa water was flushed to the waste disposal plant.
The results of the decontamination were very good. The first solution, which was only supposed to condition the adherent material for removal by the second solntion, actually caused a 50% reduction in general radiation levels. The
~ '
-j complete results follow:
Contact Radiation Levels in _mr,/_hr Location on After After #2 v h Hr After Heat Exchanger, As Found #1 Solution Solution & Flush Return to Service
('
Inlet line 30 22 h0 10 Outlet line 25 18 35 10
'='
North End h0 20 100 8
South Ihd 150 15 8
10 Top-1cng Axis 200-250 100-150 20-25 10-12 Bottom-long Axis 200-250 90-150 20-25 12-18 The principal radioisotope removed was Ag-110 m, which remains from control rods that were last used during Core II. The tank used for the so-lutions showed an increase in contact radiation level from about 1 mr/hr to 30 mr/hr apparently due to the plating of some of the Ag 110 m on the inside surface of the tank.
A radiation survey of the fuel chute lower lock valve compartment showed 2-10 mr/hr in the tunnel, 300-500 mr/hr general area in the compart-ment, arxi 10 r/hr maximum contact with the motor operated lower lock valve.
A radiation survey taken in the radioactive pipe tunnel between the
^
'7 primary auxiliary building and the vapor container showed a general level of j
30-50 mr/hr. Contact levels on individual lines were; 30-50 mr/hr on the charging line, 50-100 mr/hr on the bleed line, and 10-30 mr/hr on the safety injection line.
_8_
n,_,
A radiation survey was made in the gravity drain tank cubicle prior to cleaning with the following results:
15-25 mr/hr gensral area, 150 mr/hr on contact vi d the vapor con-tainer drain tank, and 1CO mr/hr one foot inside the gravity drain tank man-way. The vapor containe? drain tank was flushed and drained. This reduced its radiation level to 10 mr/hr but did not affect the general area levels.
A total of about 5 ft.3 of slime was removed from the surface of the tank and divided into two 55 gal. drums. The radiation lovels on contact with the drums before solidification were 250-275 mr/hr.
Personnel exposure for Yankee plant personnel as measured by film badge for the month of February 1%6 was:
's Average for all station personnel
$$ mrem (V
Maximum individual exposure 251 mrem Operations The following Emergency Instruction was revised and reissued during the report period:
Emergency Instruction gg Er50$B1 - Emergency Shutdown From Power Attached is a summary of plant operation statistics for the month of February 1966, and a plot of daily average plant load for the same period.
O k_
')
)
a
~/
- )
(-
(
C)
YANKns ATOMIC ELECL 4 COMPANY -- OPl.. FING SUleMARY C/
FEBRUARY 1966 ELECTRICAL MONTH YEAR 10 DATE Gross Generation WH 123,286,600 261,359,500 5,252,200,h00 Sta. Service (While Gen. Incl. Iosses)
WH 7,311,h56 15,h60,1hl 361,872,635 Net Generation WH ll5,975,1hh 2h5,899,359 h,890,327,765 Station Service 5.93 5.92 6.89 Sta. Service (While Not Gen. Incl. Iosses)
WH 20,091 20,091 22,261,669 Ave. Gen. For Month (672 hrs)
KW 183,h62 Ave. Gen. Running (669 hrs)
W 18h,285
' PIANT PEFORMANCE Net Plant dficiency 29.25 29.23 28.31 Net Plant Heat Rate Btu /WH n,668 H,676 12,055 Lbs. Steam / Net KWH 13 9h
- 13. 9h Circulating Water Inlet Temp.
guimnm F
37 h0 i
Minimum F
33 33 Plant Operating Factor 98.35 99 02 69.20 Reactor Plant Availability 99.67 99.8h 81.n WNTH CORE V TO DATE
- NUCLEAR Times Critical 1
15 372 Hours Critical HRS 669.78 2637 50 38,598.h6 Times Scrammed 1
1 50 Equivalent Reactor Hours @ 600 IWt HRS 660.89 2h8h.69 28,6h3.73 Average Burnup of Core IMD/Mru*
Control Rod Position at Month Ed Equilibrium at $99 IMT
- REION ENTH TOTAL BURNUP Group A Rods out-inches 69 Group B 873 A (INN E) 68h.99 18,382.88 Group C.
873 B (MIDDLE) 89h.79 10,1hh.h2 Group D 873 C (0UT E) 700.83 2,576.9h ZIRCAIDY TEST ASSDELIES H05.80 h,318.72 Boron 518 ppm Ammonia
< 1 ppm
/N
/
\\
(
d O
e O
fj)
YANKEE ATOMIC ELECTRIC COMPANY DAILY AVERAGE LOAD for FEBRUARY 1966 150 -
(a) Shutdown 81 - $ - 2 1
(b) Power dip to 30 We i
~
(c) Power dip to 30 We 100 -
~
S g
s W
50 -
U2 O
W g
l B
b 5
10 15 20 25 30' DAYS
~
4 n_
D.
\\/
CORE V REDION IDCATIONS 1
l l
REDIi)NC l
l REDI 41 B D
RIDIi MA O.
1 i
l l
1 D - ZIRCAIOY TEST iSSDGLIES o
J e,
,_-.e w.
,-,,,.y--
. _ - -,. + _,.,m,,-.-.
.-.,.-%,....-e._
.,3.,
..w...w..,,.
,_-.y,
-