ML19351E004

Operation Rept 20 for Aug 1962

ML19351E004
Person / Time
Site:	Yankee Rowe
Issue date:	09/18/1962
From:	YANKEE ATOMIC ELECTRIC CO.
To:
References
NUDOCS 8011250394
Download: ML19351E004 (11)

Text

{{#Wiki_filter:r ~ F 4 '] -^ 4,u,o d a w y, YANKEE NUCLEAR POWER STATION f OPERATION REPORT NO. 20 e 9 For the month of 4 cR tc40 ['h,[h;s* {. ' (gg{ {_ AUGUST 1962 z. ., ~ ' ' ST. -l . /" ; _ * ' ~ s \\ 10 O O O Submitted by YANKEE ATOMIC ELECTRIC COMPANY Boston Massachusetts September 18, 1962 O sonano39y

~ ~ -: F ? s cn 7 R [) . This ' report covers the. operation of the Yankee Atomic Electric ~ Company plant at Rowe, Massachusetts for 1the month of August 1962. The. refueling-period continued.throughout the month with the-plant being maintained in a cold, depressurized and borated condition.- Since replacement of fuel, control rod absorber sections, and various component inspection: programs had been completed in July, major activity. during. the month ' centered upon reassembly of the vessel internals,-decon. tamination of the: refueling area and installation of the reactor. vessel head. Assembly of the new control rod followers 'to the'already installed. new control rod absorber sections was completed.on August 15.. This involved ~ removing each of the 21 control rods from the core, one at a time, replacing the used follower section with a new one and reinstalling the unit in the ' Core. 'O~ Ten vesee1 meteria1 irredietion specimen esee h11es were a1so installed into the reactor vessel on ' August Lt. Each assembly contains a number of specimens machined from both Yankee vessel shell plate and -United States Steel reference material. Eight assemblies were located in the area between the core and the thermal shield, two of these being. equipped with neutron detectors. The remaining.two= assemblies were placed in the lower flux region between the thermal shield and the reactor vessel wall. One of these assemblies contained a neutron detector. ~ The inspection of the -fixed shim rods during July showed'some evidence of wear'on the vane surface of the zircaloy section at an elevation corresponding to that of the upper core support plate. It was' considered l that the observed wear was due to fretting corrosion between the zircaloy shim rod and-the stainless steel guide blocks. - In order to ' assist in future evaluation -of this condition, a tight fitting stainless steel cap was in-stalled at the top'of one of the eight shim rods. One zircaloy shim rod Q_ section was also replaced with one incorporating.a stainless stee3 auapter section, similar to that used on the replacement zircaloy follower sections. ~v Early in the month, work was completed on the replating of the . bottom threaded portion of the reactor closure studs. The procedure used for this operation was as-outlined'in the July Operation Report, with a total of 39 out-of'the $2 reinstalled closure studs being replated in this

manner.

During the period August 7. through 12, a series of operational-difficulties.were encountered upon reinstallation of the in-core instrumen-tation structure and upper core barre 1~ and' core cupport plate. Underwater storage of these components had'apparently been effected in a tilted con- ~ditions although contiderable care had been exercised in leveling-the storage pads.before filling-the shield ' tank cavity with water. This problem, to-gether:with that of lif ting both the upper core support barrel and in-core . instrumentation structure as a unit,' led to damage ~of two in-core instra-Q-- mentation thimbles. The damaged thimbles were cut and removed from a point R

m g o: 0 , nO -just below the upper eggerate and the remainirg thimble ends plugged at the thimble' tube sheet located at_the top of one of the structure's columns.- The insertion of the remaining 20 flux wire thimbles into Lue core was accomplisned on August 13. By August 16, the~ remaining vessel internals, including the various guide and holddown plates and 2h modified control rod drive shafts, had been assembled and preparations were in progress for drainirg the shield tank cavity. During this operation, cleaning of the walls was attempted according to planned procedures. Upon draining to about an eight foot depth, however, it became evident that working area radiation levels were much higher than anticipated. Various decontamination pro-cedures were tried at this time but without success. Radiation levels remained at approximately 100 mr/hr at the top edge of the cavity during G] these initial wall cleaning operations. r A thorough investigation of decontamination practices, proce-dures, and experiences of other reactor operators was initiated. Based ca the experience of others and analysis of the contamination present, it was decided to completely drain the shield tank cavity in order to permit the use of more effective decontaminating agents. Radiation levels as measured at the top edge of the cavity then increased to 200 to 250 mr/hr. On August 20, the reactor vessel head was temporarily installed in order (,) to afford the maximum shielding possible from the vessel internal components. v Continued effort was directed toward removing the contamination from the shield tank cavity walls and floor during the period from August 20 to 25. Radiochemical analysis showed that greater than 90% of the activity was being caused by Silver-110 m, depostted on the stainless steel surfaces by electrochemical action due to 1,he difference in potentials of silver and stainless steel when immersed in an electrolyte. Laboratory q) experimentation ~ with various decontaminating agents, as well as reverse plating schemes, resulted in repeated washing applications of 30% nitric acid solution and Chemelean a commercial decontaminating agent. At the close of the decontaminating operation and after the installation of 1" thick lead sheet on the floor of the cavity, radiation levels as measured at the top edge of the shield tank cavity were approximately h0-50 mr/hr. As an auxiliary means of reducing personnel exposures, three portable. shields in the form of three-sided steel cubicles were constructed for use on the floor of the shield tank cavity during the vessel head bolt-up operation. Radiation levels, measured in the interior of these portable shields while in the working position adjacent to the head, showed values of 30 to 90 mr/hr. Removal of the vessel head to its former storcge location under-neath the vapor container was accomplished on August 27, in order to assemble onit all equipment possible before final installation. On August Q 29, a dye penetrant check was performed on the vessel head stainless V cladding. The test results showed no evidence of cracks or fissures in the. test area. During the same day, the vessel head was replaced in position

m y;-, c ~ m 1 .e v. 3 -- .. N

1. I Ton lthe reactor.versel.i At the close of the period, the vessel stud holes-

~ '.were being cleaned and a. total of 12 vessel closureEstuds had been rein-stalled.- ' _ Primary plant maintenance operations were primarily. concerned- - with valve modifications.and maintenance on those valves-located at low elevations in the primary ' system, while secondary plant maintenance -involved modification of the steam vent line' and completion of _ the turbine-generator inspection. Maintenance Following is a-~sunmary of major activities carried out by the plant maintenance personnel during kagust. Primary Plant' 1. Adjusted the motor operator on No. k loop safety injection valve and drain valve. 2._-Interchanged manual.and motor operated bleed line valv_e bonnets in order;that the manually opera +;d valve be-located on the pressurized side of the motor operated ' valve. ~O 3-1=erectea e=a c1e =ea >=ee===1=er ar 1= ve1'e-t 99ea i= ' the seat, relocated the stem leak off connection and in-stalled a new motor operator. h. Installed a new pressurizer spray line isolation valve lo-cated between the spray valves and No. 2 main coolant loop piping.

5. Ocmpleted-the stripping, cleaning and replating of the

-bottom threaded portion of 39 reactor closure studs. 6. Fabricated three portable shielding enclosures and other various tools, fixtures and devices to assist in~ reassembly-operations. 7. Reinstalled reactor vessel upper. internals and reactor vessel head. 8. Installed two-new instrumentation cabinets in the control i room;;one to contain startup testing equipment, the other to house required inst amentaticn for higher power' operation. Secondary Plant 1. Completed modifications to the steam vent line and repairs-on-I 1 the steam dump valve. 3.--

e -e -h-f -- t 2. Installed a new low pressure turbine gland steam supply line and regulator. 3. Installed the wiring for the new turbine first stage permissive - pressure switch required for higher power operation. h. Performed a hydrostatic test on No.1 feedwater heater and completed insulation.

5. Completed turbine-generator inspection and placed the unit on turning gear.

6. Reassembled metal lagging over the high pressure turbine. Chemistry nV The nain coolant and shield tank cavity water boron concentration ranged from 1158 to 1200 ppm throughout the period. Duripg the period, the main coolant specific activity decreased from 3.h x 10-4 pc/ml to 2.5 x 10-h pc/ml. The spent fuel pit water activity averaged 2.9 x 10-3 pc/ml during the period while silver concen-tration reached a maximum value of 15 jpb. ,m(") Major effort was directed toward finding an effective chemical solution suitable for use in removing the silver 110-m activity from the stainless steel surfaces of the shield tank cavity. Determination of the activityonthesurfacesshowedittobe90to100%gilver110-mwith contamination levels in the o: der of 2.5 x 100 dpm/ft. After initial cleaning attempts using steam jet and water washing and high pressure water jet scrubbing were terminated, various chemicals were tried on test specimens. ,m Such commerical decontaminating agents as EDTA, Savasol, Weedac, and Chemelean () Nos. 128 and $36 were tried, all showing minor decontamination factors. Various other chemicals were tried, the list including caustic permanagamate, hot citric acid, hydrazine, ammonium peroxide, ammonium sulphide, and sul-furic acid anc, chromate. Again all of these accomplished very slight decontamination. Aqua regia was found to accomplish excellent removal of the act'ivity but its use on the surfaces and equipment was judged to be too hazardous. Representatives of MTR and Allied Chemical Corporation recommended the use of decontaminating solutions containing sodium cyanide or potassium cyanide. Solutions containing these chemicals were not, however, used during the refueling period but are under consideration for future use. A 30% nitric acid solution used on a previously heated sur-face was found to be the most acceptable for use under the existing conditions, with typical washings producing decontanination factors of 3.3. Analysis of pipe specimens removed from the shield tank cavity water were performed in an attempt to determine the amount of silver present on the cavity surfaces. These samples, if representative, would n indicate the presence of 8h0 milligrams of elemental silver and 6h micrograms of silver 110-m nuclide.

P Health and Safety Liquid waste with a total activity of 0.h millicuries was discharged from the plant during August. Eighty-two drums of solid waste containing 358 millicuries were chipped for off-site disposal while 82 barrels of solid waste containing 36h millicuries were drummed during the same period. At all times the concentration of waste products dis-charged or shipped from the site was well below the maximum permissible. No gaseous waste was discharged from the plant during August. Radiation levels in the working area during the rMging oper-ation for reinstallation of the upper core support barrel and in-core instrumentation structure were h0 to 100 mr/hr. Contamination in the area, in particular on the charging floor around the edge of the shield tank cavity ranged from 10,000 to 50,000 dpm/ft2 with a maximum level of 300,000dpm/ft2 by the ladder to the cavity. The radiation levels on hoses, ropes and electrical cords which contacted shield tank cavity ~ water were 200-700 mr/hr, while levels measured on contact with the two of the lamps having rubber insulated electrical cords ranged from 2.5 to 15 r/hr. A check of the radiation level at the top of a control rod guide tube, raised some 18 inches above the water and measured in contact showed 1.2 r/hr, while the level at one foot was 250 mr/hr. - s As indicated previously in this report, considerable effort was directed toward monitoring and naintaining satisfactory working area radiation levels both in and around the shield tank cavity. Radiation levels near the surface of the cavity walls after draining one-half of the cavity water ranged from 200 to 300 mr/hr,2while smearable contam-ination levels were in the order of 107 dpm/ft After the shield tank cavity had been completely drained of water, radiation levels measured m on contact with the floor of the cavity were in the order of 1.5 to 2 r/hr before the start of cleaning operations. Upon completion of the chemical cleaning and flushing operations, smearable contamination levels had been reduced to 106 2 dpm/ft, and after the installation of 1" thick lead sheet on the floor of the cavity, radiation levels on the charging floor at the edge of the shield tank cavity measured h0 to 50 mr/hr. General shield tank cavity radiation level measured 3 feet above the floor was 200mr/hr. Radiation level on contact with the stud hole plugs and the lower vessel flange was 150-300 mr/hr as measured from a portable shield and h00-500 mr/hr as measured outside. General area radiation levels inside a portable shield, while in position at the vessel flange, ranged from 30-50 mr/hr toward the rear to 70-90 mr/hr at the front. During cleaning of the reactor head for the dye penetrant check, radiation levels in the working area were 20-200 mr/hr. Measure-ment of radiation level on contact with the dye check area showed 1 3 r/hr, while the level at 1 foot under the head was 800 mr/hr. 4

r =- 7 20 j. gg f The radiation levels measured on the. reactor head located on the flat car underneath the vapor container after the coil stacks had been replaced, were 10 mr/hr at the bolt circle. Radiation levels measured on contact with tne coil stacks were 80-100 mr/hr, while at a distance of 3 feet above the head a level of 30-h0 mr/hr was recorded. General area radiation level of the decontamination room was 2 2-10 nr/hr, with contamination ranging from 5,000 to 25,000 dpm/ft, General area radiation level of the decontamination pad was 20-160 m/hr 2 while contamination of this area showed levels of 30,000 to 90,000 dpm/ft, The maximum personnel exposures as neasured by film badges for the months of July and August were 1000 and-1200 mr, respectively, while the average exposures were 23h and h80 r, respectively. Continuous monitoring of off-site airborne activity during August indicated levels consistent with pre-operational values. !g) Reactor Plant Performance l With the plant shut down during the month of August, no reactor plant performance determinations were carried out. Preparations for Core II power testing were, however, completed by the preparation of written procedures and the planning of test schedules, nU Re-evaluation of the excess reactivity data obtained during xenon free, zero power operation of Core I was also completed. Those data indicate that the use of control rod worths, determined at the h000 hour shutdown and programmed criticality data obtained during the 2000 hour shutdown, provide the most reasonable estimate of core reactivity behavior. This work also indicated that interpretation of reactivity data obtained by integration of incremental control rod worth data obtained (') as a function of rod position was in error. It was found that the rod data is should have been treated as d Keff and not as A p. Based on corrected values of core Keff as a function of burnup, it was determined that the least square fitted reactivity burnup rate from 1829 to 10,675 EFPH392 was (-8.9, 0.1) x 10-6 g gggf EFPH392. The following tabulation shows the corrected values of Keff as a function of core lifetime: CORE I BURNUP CORE I Keff EFPH MWD Evaluated for $lh0F, 2000 psig, Xenon free, G 392 WT MTU Zero Power, All Control Rods @ 90", Zero Boron 0 0 Keff = 1.115 (This data La.arium free.) O 1,829 1,h29 Keff = 1.096 (This data for equilibrium Samarium. ) U 3,835 2,996 K rf = 1.079 e 6,h00 5,000 Keff = 1.056 a 10,675 8,3h0 Keff = 1.018

& p) Q Design Changes-The followirg minor changes in plant design were completed during August: 1. Faternal and internal modifications were made to No.1 feedwater heater. The external modification consisted of providing an additional steam supply inlet to the upper section of the shell by extendirg the existing steam supply line and adding an inlet mozzle to the heater. The inter- -nal modifications consisted of adding a deflecting baffle opposite the new steam inlet nozzle and capping the internal vent.line. These modifications were made to inprove the thermal performance of the heater and also to provide for ( ) increased heater capacity in anticipation of higher power operation. 2. The sequence of the motor operated and manually operated valves in the nain coolant system bleed line was reversed, resulting in the manually operated valve being installed on the pressurized side of the motor operated valve. The change in valve sequence was accomplished by an interchange of valve bonnets only. As a result, ease of maintenance p/ L. on the motor noerated valve will be greatly improved since complete isolation is now possible. This charge is in accordance with Proposed Change No. 2 submitted en Febru-ary lb, 1961, and approved by the A.E.C. on May 25,1961. 3. Ten special tube assemblies containing encapsulated spec-imens of reactor vessel material were installed in the p reactor vessel. Eight assemblies were placed in holes v provided in the upper flange of the core baffle, pernitting the specimens to hang inside the core barrel, and two assemblies were inserted into guide channels attached to the outer surface of the thermal shield so that they are located between the thermal shield and the reactor vessel wall. Contained within the support tube of certain spec- ~imen assemblies are capsule type neutron detectors. The installation of these test specimens was made in order to determine the long and short term effects of neutron bombardment on the physical properties of the reactor vessel material. This change is in accordance with Proposed Change No.11 submitted on December 6,196'1, and the Supplement to Proposed Change No. 11 submitted on February 9, 1962. Approval of this change by the A.E.C. was received on March 26, 1962 O v A

v.- +Y ' 7 v 14 Two capped stem isolation' valves were installed in the spray line to the pressurizer, one located between the spray valves and the No. 2 main coolant loop piping and the other located in the line adjacent to its connection to the top of the pressurizer. Installation of these valves has eliminated the need for depressurizing and draining the primary system in the event maintenance becomes necessary on the spray line or its contained valves. This change is in accordance with Proposed Change No. 12 submitted on December lh, 1961, and approved by the A.E.C. on May 16, 1962.

5. Twenty-four control rod drive shafts were replaced with slightly modified shafts which inccrporate couplings of an p

\\ alternate design and certain other minor changes at the m upper end of the drive shaft. The original design of the coupling mechanism and its fingers allowed small axial backlash clearances between the fingers and the control rod adapter surfaces when in the engaged position. The mod-ifiad finger contour, its engaging mechanism, and locking features eliminate joint backlash thereby minimizing wear between mating surfaces. This change is in accordance with ( ') Proposed Change Nos.12 and 28 submitted on January 10, 1962 and July 25, 1962, and approved by the A.E.C. on April 9, 1962 and August 3, 1962, respeetively. 6. Additional equipment was installed as part of the nuclear instrumentation system in order to provide additional initiating signals for high neutron flux reactor scram during power level operation. The original protection ( ') against high neutron flux levels consisted of a coincident scram circuit which functioned when two out of three power '~ range channel outputs exceeded the selected scram set point. Due to the fact that indicated levels of neutron flux are not necessarily proportionni to actual power 7.evels during control rcd motions which accompany load changes, installation of additional power range scram circuitry on the three compensated ionization chamber out-puts was made. Protection against high neutron flux levels has therefore been increased since provision is now made for the coincident scram circuit to function when any two out of six outputs exceed the scram set point. This change is in accordance with Proposed Change No. 23 submitted on May 9, 1962, and approved by the A.E.C. on August 23, 1962. 7. Twenty-four zirealoy follower sections were replaced with new sections of a slightly modified design. Incorporated in the modified design is a stainless steel end adapter at

p .. / ) the upper end of the follower so that the joint between the follower'and the absorber section now involves contact between stainless steel and stainless steel rather than batween zircaloy and stainless steel as in the original design. Operating experience showed that slight relative motion between the materials of the original design gave use to excessive wear of the zircaloy naterial. This change is in accordance with Proposed Change No. 25 submitted on July 17, 1962, and approved by the A.E.C. on July 27, 1962. In Plant Training One sponsor company engineer returned to the plant for a period of one week during the month in order to complete a training assignment. (q Plant Operations v Attached is a summary of plant operating statistics for the month of August 1962 Sinec the plant was shutdown throughout the period, the plot of daily average plant load has been omitted. (3 Nj t v O

O O O O O- (* YANKEE ATOMIC ELECTRIC COMPANY - OPERATIE

SUMMARY

AUGUST 1962 ELECTRICAL HON",H YEAR To DATE Gross Generation KWH O 369,173,700 1,330,521,000: Sta. Service (While Gen. Incl. Losses) KWH 0 30,028,3h9 107,560,h31 KWH 0 339,1h5,351 1,222,960,569-Station Service 0 8.13 8.08 Net Generation Sta. Service (While Not Gen. Incl. Losses) KWH h03,328 2,089,h91 12,181,209 Ave. Gen. For Month KW 0 KW 0 Ave. Gen. Running PLANT PERFORMANCE 28.78 Net Plant Efficiency 11,658 Btu /KWH Net Plant Heat Rate 1h.05 Lbs. Steam / Net KWH Circulating Water Inlet Temp. 0F Maximum 0F Minimum 0 hl.66 56.35 Plant Operating Factor MONTH CORE I TO DATE MUCLEAR Times Critical HRS O 262 262 i Hours Critical 0 13,2h7.h3 13,2h7.h3 Times Scrammed HRS 0 30 30 Equivalent Reactor Hours @ h85-Et MWD /mtU 0 8,628.5 8,628.5 Average Burnup of Core 0 8)h9 8,3h9 Control Rod Position at Month End Equilibrium at-l Group 1 Rods out-inches Group 2 g SHUT D0'dN Group 3 FOR REFUELING Group h 3roup 5 Group 6

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me' 7,i }*} < y m 1This; report covers the operationiof._the-Yankee Atomic Eleetric Company j ; plant at Rowe,) Massachusetts _for the month of July 1962. The plant remained in a cold,'idepressurized and borated condition (throughout the period. On. July 3rd, refueling of the_reac % r was completed with -the-insertion of-nineteen new fue.L assemblies in the Northwest quadrant of the core.. A borescopic in'spection of the lower core support plate and source' vanes 4during the operation showed_ no unusual conditions. ~ -Operation of the fual handling equipment during the-refueling was quite smooth in general with as many as 18 fuel assemblies being unloaded or loaded

during a. ten hour shift.

During July an underwater examination of two spent fuel assemblies pro-posed for use in an extended burnup test in Core II was made. The inspection was conducted in the shield. tank cavity using a borescope and binoculars for viewing. ~No dimensional ~ distortion of the assemblies was evident nor was any crud buildup ~ detected. With the visual inspection disclosing no defects, the two assemblies { were. judged to be suitable for the extended-burnup test and were reloaded in the Js _ core. With refueling-completed,a thorough inspection of Core I control rod-absorber sections was conducted. underwater in the spent fuel pit. Peeling of the nickel plating on'a number of absorbers vas. quite pronounced. The actual lifting.of the nickel plate was visible on certain vanes while on others the surface color and texture-indicated that the plate had probably been removed ~ prior to the inspection. The degree. of removal ranged from a relatively small- %. area 'on some absorber vanes to as much as 80 percent of the area on other absor-ber vanes. . Vertical scratches ranging from a few inches to th'e total absorber - section length were detected on some of the vane surfaces. - The addition of rubbing straps on Core II absorber vanes should prevent such surface scratches. Periodic inspections of a Core II control rod absorber section have h' been in progress since installation of the new absorbers in the reactor. A slight removal of the nickel plating has been detected on one vane of the absorber under surveillance. Representatives of the Westinghouse Atomic Power Department under an. A.E.C. contract' conducted an underwater inspection of fourteen Core I fuel assemblies and selected Core I control rod absorber sections during July. Eleven, one inch diameter discs were punched from two of the absorber sections for metallographic analysis.. On July 30, the-first shipment of control rod followers for use in . Core II arrived at the plant. The new followers differ from the Core I follow-ers in that a stainless steel end adapter has been provided at the upper end of the zircaloy follower so that the joint between the follower and the absorber. section will involve stainless to stainless, rather than stainless to zircaloy

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4: K y r f q ? " contact.t 3 It is expected that this. mcdified.~ design will result in eliminating .or substantially; reducing: wear in the absorber -- follower joint. -During ' the latter part_.of :the -period the new control rod drive shafts Jand: couplings.obtained for use in Core II'were returned to the manufacturer for modification. <Khile the.new couplings were of an improved design further - ' modification-was deemed advisable to insure that the rapid' acceleration and -

deceleration 11nvolved in the stepping operation will not result in relative motion, with_ attendant possibility of wear, between any of the mating parts c of the drive linkage.

~ During ths last week of-July, replating 'of-the bottom threaded portion - of the: react'or closure studs: commenced._ The operation entails rust removal,

stripping of the' original silver plating,l immersion in a h500F oil bath for approximately one hour, cleaning (oil. film removal), silver plating and finally, -

~ balsing the newly plated stud ~1n an air balse oven at h00 F. Approximately_h0 .of the $2 closure studs willie replated with three having been replated by the end;of the period. Bolt stretch lon six main coolant pump flange bolts was measured during t the period. ~No measurable increase in bolt' length was detected. Primary plant maintenance' operations were centered about modifying several high ' pressure, _ stem leak off ' type valves; while in the secondary plant reassembly of the turbine and modification of No. 1 feedwater heater were major b projects.during, July. Maintenance - Following is:a sumnary of major activities carried out by the plant maintenance personnel-during July. Primary Plant q h-1. Replaced the fuel chute' dewatering pump motor. The original pump motor failed in the latter' stages of refueling. 2. Hydrostatically tested the blanked connections for a future safety-injection pump. -Installation of the valved and-blanked -connections was. reported'in Operation Report No. 18 -3. -Installed a new seal in No. 2 stripper bottom pump. h. Checked all electrical connections at the vapor container penetrations.-

5. Installed a ? demineralized water supply line to the vapor container -

for shield tank cavity. decontamination. v_

1 s. _3 -s 6. Installed piping for a shield tank cavity water direct purifi-cation system. 7. Repaired the oil seals on No. 3 charging pump hydraulic coupling. 8 Commenced cleaning, stripping and replating reactor closure studs. 9. Revamped air baffles for control rod drive cooling to facilitate assembly and disassembly. 10 Modified several primary system, stem leak off type valves. Included in the valve repairs and modifications were the instal-lation of new stems and backseats, lantern ring changes and valve bonnet changes designed to raise the leak off connection on the bonnet.. The operating history of these valves has indi-cated poor backseating, excessive leakage and difficulty in-repacking. I I ' Secondary Plant 1. Reinstalled the exciter and its electrical connections. 2. Reinstalled the turbine high pressure spindle, blade rings and casing. ( ' / 3. Reinstalled the turbine low pressure casing. h. Started modifying No. 1 feedwater heater. Chocked and calibrated secondary plant instrumentation. Chemistry ,m The main coolant and shield tank cavity water baron concentration () ranged from 1150 to 1160 ppm throughout the period. During the period the main coolant specific activity decreased frors 6.1 x 10-h Sc/ml to 3 3 x lo-h sc/ml while -the shield tank cavity water activ-ity decreased from 8.2-x 10-3 sc/ml to 2.h x 10-14 sc/nl. The spent fuel pit showed a similar decline with the activity dropping from water activity /ml at the beginning of the period to 2 3 x 10-3 pc/ml at the end $.5 x 10-3 pc of July. A shield: tank cavity %r ion exchange connection was made during July to permit purification of Id tank water without passing the water through the shutdown cooling sy 1 By the end of the period a 30 gpm purification flow had been established through the new connection to a cation exchanger bed. m k W

L ...s .= ' ~. ~ s y _. n Purification-of' spent fuel ~. pit water continued during' July. through ja mixed bed iontexchange unit. . Dissolved oxygen analyses of water in the secondary side of the steam generators indicated concentrations of O. to 15 ppb. Reactor' Plant Performance. Reactivity effects Xenon poisoning measured during Core I lifetime were as follows: ~ ime Required T Equilibrium-to Reduce Elapsed Time ' Power Prior Power from to Peak Ienon EFPH @ Peak Xenon to Controlled Equilibrium after Reaching 392 Et-~ Poisoning- ' Load Reduction Power to 0 Wt 0 Wt (321 1 ) x 10- k. 392 Wt 0.6 hours 6.h + 0.8 hr. 8 1829 3835 (350 1 5) x 10-h8 h85 W t 0.9 hours 6.5 1 0.2 hr. 6h00 (300130) x 10-k - 385 W t 0.9 hours 5.5 1 1.0 hr. 10,675 '(2ho 1 h).x10-k .262 Wt 1.0 hours b.6 1 0.2 hr. Turbine Plant Performance With the plant. shut down during the month of July, no turbine plant performance determinations were possible. Design Changes The following minor changes in plant design were completed during 1. Piping was installed between the shield tank cavity drain line and ion exchange inlet header and between the ion exchange outlet header and an existing capped and valved connection on the safety' injection tank' inlet line. The new piping arrangement permits. purification of-shield tank cavity water without passing it through the_-shutdown cooling system. By virtue of the modification, shield tank cavity water can now be circulated from the cavity drain line by gravity feed through an ion exchange bed and thence to the safety injection tank. From the safety injection tank the charging pumps transfer the purified water back through the main coolant loop connection p, 'Q)

y into the open "eactor vessel and up into the shield tank cavity. 2. A domineralized water supply line was installed during July. The new line originates at the low pressure surge tank make up pump discharge and terminates on the vapor container charging floor. The installation provides a demineralized water supply for decontanination of the shield tank cavity and also cerves as a feed for the jacking pump supply tank. Healta and Safety Liquid waste with a total activity of 2.2 millicuries was discharged from the plant during July. Sixty-four drurs of solid waste containing 155 millicuries were shipped for off-site disposal while 67 barrels of solid waste containing 258 mil 11 curies were drummed during the same period. At all times the concentration of waste products discharged or shipped from the site was well below the maximum permissible. C(m No gaseous waste was discharged from the plant during July. Radiation levels in the working area of the spent fuel p:.t during inspection of Core I control rods by Westinghouse personnel were 10 to 15 mr/hr. 2 Contamination in.the area ranged from 1000 to 10,000 dpm/ft. The radiation level measured on contact with a disc punched from a Core I control rod absorber sectionwas1r/hr. The maximum radiation level from one of eleven punched n I ) discs was $ r/hr measured at a distance of three feet from the disc. During the period drive shafts used with Core I control rods were removed from the shield tank cavity and placed on the decontamination pad. The drive shafts, with contact radiation levels of 3 to 12 r/hr at the dash-pot end, were placed in polythylene tubing prior to transfer through the vapor container equipment hatch. Shielding in the form of concrete blocks was provided to reduce radiation in the vicinity of. the decontamination pad. (9 - General area radiation levels on the charging floor ranged from O.5 to $ mr/hr with levels of 15 to 25 nr/hr measured near the edge of the shield tank cavity. The radiation level measured over the edge of the spent fuelpitwas15to20mr/hr. Radiation levels measured at the surface of the centrol rod and fuel assembly transfer rack used by Westinghouse personnel in their Core I fuel and control rod inspection were 500 mr/hr at the guide plate,1 r/hr at the bearing plate and $0 to 200 mr/hr over the remainder of the rack. Following the inspection the rack was dismantled for disposal with solid wastes. 41

Vy c =; y .. ~, ?:s in E ' -D. L Radiation levels in-the: working area during eleetrical and mcchanical ' maintenance on valves'in the main; coolant lorp during July " sere as follows: Radiatidn Level-1 Valve: MC Loop mr/hr~ tBy-paas valve-1 ~ 80.

Drain valve

'2 100-200' Stop valve.

2 20-30

'.By-pass valve-h- h0-90 Safety injection valve

h 20-30'

. Drain valve - h 50-80 . Radiation ~ levels were measured in close proximity to a Core I control rod absorber section and three Core I fuel assemblies during the period. The measurements were made underwater using EG & G dosimsters. Following are the rasults :: Radiation l Measuring Measuring Level Location . Distance <vinches r/hr Control ~ rod absorber ' Axial center 12 6,h00 q - - Fuel assembly (from - -Q Axial center -1 372,000 innermost section of . Core I) Axial' center 12 28,800 .2_ inches below 12 12,000-top of assembly-hlmidwaybetweencenter Fuel assembly-(from Axial center 12 25,800 and ' outer. edge of..- (Core I) _ Fuel assembly (from. Axial center 1 126,000 . outer;e'dge.of Core I)' -Axial center 12 -8,h00 2 inches'below. 12 3,h00 itop.of' assembly Since the preceding measurements were made-under water the measuring distance is equal to the water shielding between the dosimeter and radioactive -l component.' - ~ [(,]'-mon... .. The-raximum personnel exposure as measured by film badges for the' th1of June '1962 was 1160 mr ;while the average exposure was $10 mr. - s 4; C y y 4 r 44 4

t l l

O Continuous monitoring of off-site airborne activity during July l

inaicated levels consistent with pre-operational values. In Plant Trainira One sponsor conpany engineer and two Solni project representatives completed training assignments at the plant during July. Plant Operations Attached is a sunnary of plant operating statistics for the month of July 1962. Since the plant was shutdown throughout the period, the plot of daily average plant load has been omitted. O 1 O l O ! O

I l I l i YANKEE ATOMIC ELECTRIC COMPANY - OPERATIN3

SUMMARY

l JULY 1962 MONTH YEAR TO DATE ELECTRICAL Gross Generation KWH 0 369,173,7ed 1,330,521,000 Sta. Service (While Gen. Incl. Losses) KWH 0 30,028,3L9 107,560,h31 Net f'eneration KWH 0 339,1h5,351 1,222,960,$69 Station Service 0 8.13 8.08' Sta. Service (While Not Gen. Incl. Losses) KWH 376,772 1,686,163 11,777,881 Ave. Gen. For Month KW 0 Ave. Gen. Running KW 0 PLANT PERFORMANCE 28.78 Net. Plant Efficiency 11,858 Net Plant Heat Rate Btu /KWH 1h.05 Lbs. Steam / Net KWH Circulating Water Inlet Temp. 0F h um 0F Minimum 0 h7.76 01.hh Plant Operating Facter MONTH CORE I TO DATE NUCLEAR 0 0 262 Times Critical HRS 0 0 13,2h7.h3 Hours Critical 0 0 30 Times Scrammed HRS 0 0 8,628.5 Equivalent Reactor Hours @ h85 MWt Average Burnup of Core MWD /mtU 0 0 83h9 Control Rod Position at Month End Equilibriun at Group 1 Rods out-inches w Group 2 Group 3 SHUT' DOWN Group h FOR REFUELI!D 3roup 5 Group 6

I e ,? i .sh < [g - ~ ~_.... sm -YANKEE NUCLEAR POWER STATION g. OPERATION REPORT NO. 18 For the month.of CN ' }:l.[]x Y ;) JUNE 1962 v u v,,. lPU Y i .b O O

- O Submitted by YANKEE ATOMIC EIECTRIC COMPANY 4

Boston Massachusetts July 20, 1962 b d 4 i O Tdili6OdTa3 ( u u 1

p.

N

This report' covers the operation'of the-Yankee Atomic Electric U Company plant at Rowe, Massachusetts for the month of June 1962

- At the beginning -of the' period the reactor was in a cold, depressur-1:ed and borated condition with preparations continuing for the actual reactor - refueling. From June 1 to June $ primary plant activities were centered on ' cutting in-core instrumentation connections at the reactor head, removing the remaining control rod drive mechanism coil stacks, cleaning the shield tank

cavity and checking out the operation of the fuel handling system. Following these operations the pressurizer water level was lowered and the remaining reactor. vessel' head closure nuts and studs were removed.

On June 6 -'the reactor head was lifted and borated water was intro-3 duced intof the shield tank cavity. The head was removed from the vapor con-tainer through the equipment hatch, wrapped in a plastic covering and placed on a flat car for temporary storage durirg the reactor refueling. . Following the head removal, the core hold down plate, control rod Q drive shafts and control rod thimbles were renoved. On June'1], preparations were made to lift the upper core support barrel and in-core instrumentation.eggerate. At this point the underwater-T.V.' camera was found to be inoperative and interference between the upper core barrel lifting rig and the instrumentation eggerate was' detected. A delay of approximately two daywas incurred while these difficulties were taken care of. Repair of a defective cable connector restored the T.V. camera to operation while the lifting rig interference was eliminated by grir. ding.five slots in the inner circumference so as to provide adequate clearance. On June lit, the upper. core support barrel and in-core inst ~umentaticn eggerate were lfited from the reactor vessel following which spent fiel renoved comnenced. By June 18, eighteen spent assemblies had been removed frw we northeast quadrant of' the core along with one centrol rod. Underwater exam-ination of the control rod disclosed some wear between the - stainless steel fin- . gers of the control rod drive shaft latches and the stainless steel adapter at A. the top of the absorber section. Possible wear in this area had been antic- . ipated and control rod drive shaft and absorber sections.of. improved design had been procured.. Uear was also detected at the joint between the circaloy follower section and stainless steel adapter on the absorber. As a result the control rod followers will also be replaced. Following detection of wear on the follower joints, a decision was - '.made to complete the reactor refueling and insert the new control rod absorber sections. Twenty-two absorber sections of revised design and two spare absor- -ber sections of the Core I: design were placed in the reactor. Pendirg delivery of the new follouers, the Core I followers were returned to-the recctor attached to the new absorbers. By June-26, the.new absorber sections had been placed in the reactor and the eight, fixed shim' rods had been removed, inspected and reinstalled in the' reactor. V-t

d A' A quadrant by quadrant unloading-loading scheme allowed examination of the bottom core support plate and source vanes after completely unloading a qu drant and prior to its reloading with new fuel assemblies. By the end of a the period borescopic examination of the core support plate and source vanes had been completed in three quadrants. In all cases no unusual conditions were noted. Spent fuel removal and new fuel insertion proceeded through the final days of the period relatively smoothly. The fuel handling system functioned well except for one brief " hang-up" of the fuel carriage on its return from the spent fuel pit. At the end of June the status of the reactor refueling was as follows: Quadrant 18 spent assemblies removed, 18 new assemblies Northeast ~ installed, 1 assembly carryover from Core I.* 19 spent assemblies removed, 19 new assemblies Southeast installed 19 spent assemblies removed, lh new assemblies Southwest installed (loading in progress at end of month) Preliminary underwater exanination of spent fuel assemblies has dis-cle 3cd no discernable distortion of fuel assemblies or significant crud buildup. While a detailed exanination of all control rods had not been made by the end of June, scratches on some of the absorber section surfaces were detected. The revised design absorbers are provided with rubbing straps which should elim-inate or at least greatly alleviate this condition during Core II operation. The nickel plating on several absorber sections was observed to have deteriorated somewhat with the nickel plating flaking off in some areas. A chemical analysis m of the flake material disclosed that it was primarily nickel with traces of silver also present. Secondary plant operations proceeded during the period with the turbine and generator inspection essentially completed. With the exception of minor erosion or cutting of a few low pressure turbine blading stellite strips and some minor erosion in the area of the inlet impulse section the condition l of the turbine was found to be good. Likewise only minor repairs were required on the generator. By the end of June both the turbine and generator were being reassembled.

• Two Core I spent fuel assemblies will be used in Core II for an extended burnup test if the results of a detailed underwater examination of the spent assemblies indicate their suitability for such an experiment.

.j --3 t -Maintenance Following is a listing of the major naintenance activity during June: 1., Tested the low pressure surge tank safety valves. 2. Repaired underwater T.V.; camera in the shield tank cavity. Water -had leaked into the fitting through which the T.V. cable enters the camera enclosure causing a short circuit. 3. Completed an inspection of No.1 loop safety injection valve, drain valve and bypass valve. 13 Inspected and overhauledzthe pressurizer solenoid and motor operated relief valves. 5. Inspected and overhauled the stop valves in the waste disposal cover gas system. l3 %/ 6. Renewed.the primary drain pump shaft bearings. 7. Rough cleaned the reactor studs and nuts. 8. Inspected the station vital bus.- p 9. Repaired the underwater viewing borescope. Lifting of the d silvered backing on a prism in the borescope necessitated its replacement. 10. Installed a new steam heating coil in the safety injection tank.

11. Installed new seals in the No.1 stripper bottom pump.

12. Installed a new diaphragm in No.1 waste gas compressor.

13. Performed calibrations on primary plant instrumentation.

-v Secondary Plant 1. Completed modifications.to No. 2 feedwater heater and conducted .a hydrostatic test on the heater.-

2. -Removed generator field and conducted tests on both stator and rotor insulation. Following the' generator inspection the field was reinstalled.

'3. Conducted magnetic particle inspection of the turbine. l i. -4

.w -k-. a qb h. Cleaned blading'on turbine rotor and diaphragms.-

5. 'Made miscellaneous repairs to turbine. Fifteen stellite strips on the low pressure spindle blades were. replaced as a result of-erosion. - A steam cut area on No. h. turbine control valve inlet flange was repaired. Seal strips in the area of the governor end impulse wheels were repaired.

. 6. Reinstalled the turbine low pressure rotor. 7. Inspected and-overhkuled the steam dump valve. The valve disc and stem were replaced. 8 Inspected secondary side of No. 2 steam generator. The general condition of the-steam generator was good with no visible pitting or corrosion evident. ~ p Chenistry O Operation of the modified waste disposal evaporator has indicated a slight boron volatility (sv0.2 w/o). A polishing ion exchanger 'will be required to make reuse of the distillate possible. Main coolant and shield tank cavity water boron concentrations re-mained at 1180 to 1190 ppm throughout the period. The main coolant crud level ranged from 0.11 ppm to 0 39 ppm while the ' shield tank cavity water crud 1evel was~ 0.7h ppm. Early in June the main coolant specific activity increased from- ~ 2.6 x 10-3 ne/ml to 3.7 x 10-2 Ac/ml. Tne increase occurred after term-ination of flow through the cation exchanger. Concurrently, the main coolant. nicke1~ concentration increased to 5 ppn -- the presence of nickel being. attributed to corrosion in cold, borated, oxygenated water of undiffused nickel plate on the reactor control rods. Resumption of purificacion through the cation exchanger decreased the nickel concentration to below the' point of detection by the end of t,he period. The predominant contributor to main coolant specific activity during thisperiod was Co-58 which is carried. with the soluble nickel in the coolant ~. The decrease in nickel concentration was reflected in the-main coolant specific activity which decreased to 1.9 x 10-3 pc/ml by the end of June. The shield tank cavity water specific activity which ranged from h.8 x 10-3 oc/ml to 5.6 x 10-3 sc/ml at the beginning of the period increased to 8.2 x 10-3 pc/ml by the end of June with Co-58 the major activity contributor. On June 16, a chromate concentration of 15 ppm was detected in the shield tank' cavity water. Leakage from the underwater T.V. camera coolirg ~ coil wa~s sus-pected as the source of the: chromate. Following isolation of the cooling coil analyses for chromate were negative. Late in the period the spent fuel pit water boron concentration reached 12 ppm. Mixed bed ion exchange of the pit -water was initiated at this time. O. 4

C1 o p.1 ^ . 1 mL)f Chemical and radiochemical analysis of flake material from the control-rod absorber sections indicated the following: Nickel 100% + 0.5% Silver 0.3% 7 0.1%. Co-58 1.5 x 10b dpm/mg Ag-100m 2.h x 105 dpm/mg Reactor Plant Performance Temperature coefficient of reactivity.results determined at varying core and coolant temperature conditions during testing at the and of Core I operation indicated the following: 1. Peak xenon, 0 ppm boron Tave. h280F, 2000 psi -1.69 + 0.0h x 10-b df/ F - q' v - 2. Xenon free, 195 ppm boron T,y,, lh20F, 2000 psi -0.70 + 0.06 x 10~b g /0F 3. Xenon free, 220 ppm boron Tave. 507 F, 2000 psi -2.36 + 0.05 x 10-b A9/ F 0 i Turbine Plant Performance With the plant shutdown during June no secondary plant performance [ data were acquired. Design Changes The following changes in plant design were completed during June: /3-1. A welded, stainless steel pipe connection for a high accuracy V nain coolant pressure gage was installed. The connection originates at a newly insta11ed' tee connection outboard of the root valve for the high pressure line to the wide range pressurizer.leveld/pcell. It terminates at the pressure measuring gage located in the primary auxiliary building. Appropriate valving for isolation of the newly installed line was also provided. This installation is in accordance with Proposed Change No. 16 submitted on January 18, 1962, and approved by the A.E.C. on March 26, 1962. 2. Two valved and blanked connections were installed in the Safety Injection System piping - one in the safety injection pump suction header and the other in the safety injection pump dis-charge header. Based on the possibility of authorization to h'

operate the plant at higher power levels and the attendent necessity for an additional safety injection pump, this change has been effected to facilitate future installation of the pump. By virtue of the suction and discharge taps now in place it will not be necessary to shut the plant down and cool and depressurire the main coolant system for installation of the additional pump. This change is in accordance with Proposed Change No.-20 submitted on March 12, 1962, and approved by the A.E.C. on May 16, 1962. 3. The electricalsupply for the radiation monitoring and feedwater control systems was changed from the existing 120 volt AC vital bus to a station service bus (h80 volt bus MCCl-Bus No. 1). This feeder presently supplies equipment including the valve operators for the safety injection system, the control rod selection and program controls, No. 1 main transformer and other essential 120 volt AC instrumentation which are vital to reliable and safe plant operation. Operation under this arrangement should effective-o ( l ly reduce the exposure of the AC vital bus to electrical grounds and consequent spurious reactor scrams. Since a brief inter-ruption of the radiation monitoring and feedwater control systems can be safely permitted during a loss of power condition, the change does not adversely affect plant safety considerations. This change is in accordance with Proposed Change No. 21 submit-ted on March 23, 1962, and approved by_ the A.E.C. on June 13, 1962. g La b. A stainless steel isolation valve and tee connection have been installed in the pressure equalizing line between the primary system safety valve discharge header and the low pressure surge tank. The tee connection is located on the safety valve header side of the new isolation valve with a capped line and shut off valve connected to the tee. The newly installed connections will simplify primary system safety valve and connecting piping maintenance by providing a means for purging the safety valve t'] header without purging the hydrogen from the low pressure surge (/ tank as had been required prior to the modification. This change is in accordance with Proposed Change No. 22 submitted on Apri~. 18, 1962, and approved by the A.E.C. on June lh, 1962.

5. Twenty-two of the twenty-four control rod absorber sections were replaced with slightly modified absorbers. Incorporated in the modified design absorber sections are longitudinal, segmented, stainless steel rubbing straps on each of the eight vane sur-faces. The rubbing straps are intended to reduce wear and abrasion of the nickel plating on the surface of the absorber sections. This change is in accorda!.ce with Proposed Change No.

13 submitted on January 5,1962, and approved by the A.E.C. on April'9, 1962. 7 a

, s j) 6'. External and internal modifications were made to No. 2 feed- ~ L' . ater heater. An additional steam supply inlet to the upper w section _of the -heater shell was provided by extending the existing steam supply line and adding an inlet nozzle. A further external modification was the additi^n of a second heater drain connection with a ~ tic to th'e existing drain line. The internal modifications consisted of replacing. sections of the horizontal baffles.previously cut away, carping the internal vent and adding a-deflecting baffle opposite the new steam inlet nozzle. These modifications were made to improve the thermal perfomance of the heater and also to increase the heater Wacity for anticipated higher power operation. 7. Minor design modifications have been made to the turbine during the current turbine inspection. Steam strainers have been installed in the four turbine control valves to improve the flow distribution and alleviate vibration in the control valve bodies. d Thirty-two, 1 3/h inch diameter moisture drainage holes have been prev 1.ded in the low pressure turbine casing during the outage. The d.ainage holes will increase moisture removal capability in the low pressure stages of the turbine. -Health and Safety Liquid waste with a total activity of 1090>1c was discharged from the plant during June. Thirty-five drums of solid. waste containing 36 milli-curies were shipped for off-site disposal while eighty-four barrels of solid. waste containing 670 millicuries were durmmed during the same period. At all times the concentration of waste products discharged or shipped from the site was well below the maximum permissible. No gaseous waste was discharged from the plant during June. The following contact radiation levels were. measured during June with the plant in a cold, borated, depressurized condition: Location Radiation Level on Contact No.1 Charging Pump 35mr/hr .No. 2 Charging Pump h0mr/hr No. 3 Charging Pump 35mr/hr Charging Line (in pipe chase) 18mr/hr Main Coolant Bleed Line (in pipe chase) 50mr/hr I Activity-Dilution Decay Tank $0 mr/hr - h r/hr Waste Holdup Tank 10-100mr/hr Gas Surge Drum 0.02mr/hr Shutdown Cooling Pump 1.5 r/hr Shutdown Cooling Exchanger 150-250 nr/hr t

..%s .6-(] Location Radiation Level on Contact Low Pressure Surge Tank'Disenarge Line 250mr/hr t Low Pressure Surge Tank Bottom 7 r/hr Ion Exchange Pit 0.2-0.5 mr/hr. Pressurizer Shell 0.h-20 nr/hr No. 1 Loop Pump 80-90nr/hr Main Piping 50-250mr/hr No. 2 Loop Bypass Valve h5mr/hr Main Piping 60-100mr/hr No. 3 Loop-Bypass Line - 30-50mr/hr Main Piping 80-100mr/hr No. h Loop Check Valve 20 mr/hr Main Piping h0-h00 mr/hr Radiation levels in the working area during cutting.of instrumen-tationsealson.thereactorheadwereh0to60mr/hrwithtemporary3/hinch ,J' thick lead shielding in place around adjacent control rod drive mechanism housings. Contamination on the reactor head and in the control rod dr mechanismareaasaresultoftheoperationwas3,000to30,000dpm/ftgve Removal of the remaining control rod drive mechanism coil stacks increased radiation levels by a factor of two at the reactor stud annulus and by a factor of four in the general area of the shield tank cavity. While coil stack removal had been scheduled for completion early in the reactor head c-removal preparations, they were left in position until their shielding effect for nearby operations was no longer needed. Radiation Levels at the inside edge of the vessel head flange during initial lif ting and prior to flooding the shield tank cavity were: Head raised 2 inches 1r/hr Head raised 12 inches 1 5 to 5 r/hr Head raised 2h inches h to 8 r/hr Measurements made by dosimeters inserted under the center of the head indicated the. total radiation from the head plus that from the core was 6 to 8 r/hr with the head raised 12 to 2h inches. During the descent of the reactor head through the vapor container - equipment hatch to the railroad flat car, the following radiation levels were 'O V s

3 .o. (^) measured 'at ground level: Measured Head Location Height above Ground Radiation Top of Equiprent Hatch 85 feet 2mr/hr Bottom of Equipment Hatch-33 feet 20mr/hr Below Equipment Hatch 12 feet 50mr/hr Following flooding of the shield tank cavity radiation levels of 15 to 30 mr/hr were measured over the edge of the cavity. General area levels on the charging floor at the same time were 0.2 to 1 mr/hr. Radiation levels increased in the vicinity of the jacking pump 'on the charging floor as the pumping of contam-inated water progressed. Radiation levels of 100 to 200 mr/hr were measured at a distance of three feet from the pump. The pump was. partially shielded by stacking concrete blocks to a height of four feet (thickness of eight inches). This mduced the radiation level outside the shield to 2 to 5 mr/hr. At the same time, a source of uncontaminated water was provided. General area contamination levels of 200 to 20,000 dpm/ft2 were measured on the pharging floor. Isolated locations on the charging floor exhibited a higher degree of contamination as a result of temporary placement of ccntaminated articles on the charging floor. In two areas maintenance on contaminated equipment removed 2 from the shield tank cavity produced contanination levels of 50,000 to 200,000 dpm/ft, At the end of the period general area radiation levels on the charging (3 floor were 1 to 5 mr/hr with levels of.10 to 30 mr/hr measured near the edge of the L / thield tank cavity.: Ogneralareacontaminationlevelsonthechargingfloorwere 2,000tolb,000dpm/ft. By the end of June a radiation level of 20 to 30 mr/hr was measured over the edge of the spent fuel pit. The radiation level on contact with the side of the fuel pit cooler was 50 to 80 mr/hr. Radiation levels measured after drainage of the secondary side of No. 2 p steam generator were 80 mr/hr at the manhole opening and 2 r/hr at the hand hole d cpenings.- -The maximum personnel exposure as measured by film badges for the month of May 1962 was 300 mr while the average was 10 mr. Dosimeter readings for the month of June 1962 indicated a maximum cxposure of 910 mr with an average personnel exposure of h80 mr. June 1962 film ba4y resulta'will be reported in the July 1962 Operation Report. The exposures indicated for May and June include all station personnel-plus ten temporary personnel assigned at the plant for the refueling operation. Continuous monitoring of off-site airborne activity during June indi- . cated levels consistent with pre-operational values. .DO

.3 I, In Plant T' rainirg ji One engineer from the Selni z : lear project completed an assignment i ' et the plant durirg June while two Selni representatives continued in their plant cssignments. i One Stone & Webster engineer and four sponsor company engineers term-inated plant assignments during the period. One sponsor company engineer remianed in training. Plant Operations Attached is a summary of plant operating statistics for the month of 4 June 1962. Since the plant was shutdown throughout the period the plot of daily average plant load has been omitted. 0 5 O 1 O. ~ 3 O'

O O o o O+-

• ~.

YANKEE ATOMIC EIECTRIC COMPANY - OPERATI!G

SUMMARY

JUNE 1962 MONTH TEAR TO IRTE EIECTRICAL 10A1 0 369,173,700 1,330,521,000 Gross Generation Sta. Service (whila Gen. Incl. Losses) EWH O 30,028,3h9 107,560,h31 WH 0 339,1h5,351 1,222,%c,569 0 8.13 8.08 Net Generation Station Service Sta. Service (While Not Gen. Incl. Losses) KWH 365,Jh0 1,309 391 11,h01,109 f Ave. Gen. For Month 10( 0 KW 0 Ave. Gen. Runnirg PLANT PERPNMANCE 28.78 Net Plant Efficiency 11,858 Btu /KWH Not Plant Heat Rate-lb.0$ Lbs. Steam / Net KWH Circulating Water Inlet Temp. 0F Maxinna 0F 0 $$.9k 6h.88 ~ Minimum Plant Operating Factor MONTH CORE I TO DATE NUCLEAR O 262 262 Times Critical 0 13,2h7.h3 13,2h7.h3 HRS Hours Critical 0 30 30 HRS. 0 8_628 5 8628.$ Times Scrassied Equivalent Reactor Hours 8 h85 left NWD/mtU 0 83h9 83h9 Average Burnup of Core Control Rod Position at Month End Equilibrium at U Group 1 Rods out-inches Oroup 2 Group 3 Shut down Group h for refuelirg Group $ Group 6 - -}}