ML20029A753

Annual Rept 1990 Illinois Advanced Triga Facility. W/

ML20029A753
Person / Time
Site:	University of Illinois
Issue date:	12/31/1990
From:	Miley G, Pohlod C, Williams J ILLINOIS, UNIV. OF, URBANA, IL
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
NUDOCS 9103040211
Download: ML20029A753 (12)

Text

.. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Uniwrsits of Illinois oceanment of courge or Inginrenng l

at Uihili$ Champaign Nutlest liigin-ning 214 Nmleas i ngineering 217 333 2295 1 aterator y 217 333 2906 f.it 10.1 South Goodwin Avenue i

Utliana.11. bi t401 2Vk4 February 28, 1991 Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission 1 White Flint North 11555 Rockville Pike Rockville, Md 20B52 i

Attention: Document Control Desk

Dear Sir:

~

SUBJECT:

ANNUAL REPORT: Illinois Advanced TRIGA Reactor License No. R-115 Docket No. 50-151 The following is written to comply with the reoutrements of Section 6.7.f.

of the Technical Specifications and the conditions of Section 50.59 of 10 CFR.

The outline of the report follows the numbered sequence of section 6.7.f of the Technical Specifications.

Yours truly, boI ) o 9

Craig S'. Pohlod Reactor Supervisor I

fQ.

p,w q.tJ

1. ohn G. Williams J

Reactor Laboratory Director i

.}

!!t 64 gay

, George H. Miley. Chafrman-1 Nuclear Reactor Committee s

6brwlw.. sue N'

BarclayG.Jpp'es,I/tjid Department-pfNuclear Engineering l

//

cc: Regional Administrator, Region III, USNRC 9103040211 901231

~

,fl gDR ADOCK0500g1

L i

ANNUAL REPORT JANUARY 1, 1990-DECEMBER 31,1990 IlL IN0lS ADVANCE 0 TRIGA FACILITY LICENSE R-115 1.

EUMMARY OF OPERAllNG E Q UJ101CE A. htrpjry af U3fg12 The reactor on the average, was scheduled f or use 30.2 hout s per week and was in operation 18.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> per week. Scheduled time decreased about 11% from last year, and actual coerational hours decreased about in. These decreases were due to a temporary decrease in research re'ated to nuclear pumped lasers and the investigation of radiation ef fects on optical materials.

In the following table, the per cent of time for different activities is litted. Scheduled time is that time reserved for a given operation, and it includes scheduling more than one reactor facility for use at the same time, while operating time is from start-up to shutdown for all the scheduled activities.

(ATEGORY ECMLQ!&[D QPERATING Research Projects 9.2%

9.9%

Irradiations 63.2%

68.7%

(Research & Service)

Education and Train'ng 18.7%

13.6%

Maintenance and Measurements 8.9%

7.8%

Presently there are two individuals with a Seniot Operator License and four individuals with an operators License. The f acility operates with a 40 hour4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> week schedule, a staf f of three and one quarter full time equivalent operators and one full time reactor health physicist.

Mr. Richard Holm (SRO) and Mr. Brian Golchert (RO) received their operator licenses in November.

P. Performance (htrgteristiqji 1.

eve 1 E10?f!LLk9ML1J1nd Diaggigr MeaqpImeats These checks were made on the B & C Hexagonals during the month of April. The pulso number at the time of the checks was 10,048. For the eighteen elements in this region, the.s was an average decrease in the length of about 3 mils. The accuracy of a given measurement is estimated at 10 mils. There was no change in the diameter of the fuel elements checked.

There were 280 pu'ses in 1990, bringing the total since 1969 to 10,24'.

i For a standard $ 3.00 pulse, the values for pulse height, reactor period and fuel temperature were the same as measured in previous years.

2.

Bta_qtlyitY (pntrol Poh: The measured reactivity values of the control rods have shown essentially no change. Variations between successive measurements are seldom greater than 5%.

2 Cor e Peactiylty: The not loss of reactivity attributed to fuel burnup during the year was S 0.49. This value was determined by a comparison of the cold cr1tical menon-free control rod position at the beginning and at the end of the year and correcting for core reactivity gained by the hddition of fuel during the year. Two fuel elements were added to the reactor core in February which resulted in a not r eactivity gain of $ 0.61. Based on an estimated 2 (10,5) cents per HW-day of operation, the r eactivity loss for the year would have been approximately 1 0.46.

II.

TAPIllATION OF TM PGY AND PULSIRQ A* kd2MfNJ 1NNMlbflCM 1YDe oGT!1ritign Tim <tJhril hu; tat _(1&hn) 0-10 kW 209.9 0.03 10.1kW-250LW 89.7 13.55 250.1FW-1.5MW E47.5 531. ti 7 Pulsing SL4d

__ L.D Total 972.0 547.01 B.

Pulsing EU h L S1Lu WLT11C

$1.00-1.70 27 1.71-2.00 14 2.01-2.30 0

2.31-2.80 12 2.81-3.19 227 Above $3.19

__Q Total 280

• -Became of the type of operation, the Hours Critical time includes instances where the reactor is not critical in the normal sense. These include the time to reach criticality during a start-up, the time between pulses during continuous pulsed operation and short periods of time during sample irradiations when samples may be removed or added.

III. DEAC10R SCRAMS There were 31 unplanned scraras and no emergency shutdowns during this time period.

These scrams were attributed to Instrument Halfunction (17),

Operator / Operator Trainee Error (12) and Esternal Causes (2). This is fewer than average for the facility over the past several years.

Linear power (14)

This is a power level scram required by the Technical Specifications. It occurs when the s1gnal on any power range exceeds about 108% of that range.

I Eight (8) of these screms were due to electronic noise problems. The source of this noise has not been found as it is intermittent. The Mode Switch is cleaned periodically and old capacitors, usually electrolytic are replaced as they are identifieci as f ailed or f ailing. One (1) of these scrams occurred when the drive

3 cords for the Linear Channel and Log N Channel became fouled in the inking system. The cords were tightened and the inking system has been r eplaced, Five (5) of these scrams occur red due to operator / trainee error. Iwo of the five occur red due to the operator f ailing to reduce power in a timely f ashion af ter cornplet ing a per 1od measurement dur ing a control rod calibration. Two of these scr ams occurred when the operator was setting up a Square weve oporat ion and failed to place the range switch on the correct rango. The last of these sciams occurred when a trainee moved a control rod too f ar while the reactor was at full power. The prompt jump in power due to control r od movement at full power cari be suf ficient to cause power to ciceed 10A if the control rod is moved continuously for raore than several seconds instead of being jogged or shimmed for a second or so.

Eat 1 ELM ram (302 k

This scram is not required by the Technical Specifications, it occurs when the period is 3 seconds or less with the Mode Selector Switch in Automatic or Steady State position. Two (2) of these scrams occurred either when the period circuit was placed in operation at too low a power level or when the true power level was taasked by high gamma current and therefore the period limiter circuit could not effectively drive the Regulating Rod in to prevent the Period Scram.

Adjustment of the Log-N Channel is not practical af ter every shutdown. This scram in usually caused by operator trainees or student operators wN] are not yet f amiliar with this behavior.

Eight (8) of these scram were due to circuit noise of an unde'sermined origin. The High Voltage Power f.upply is suspected as the cause of these scrams.

The problem appears to b9 Intermittent.

L;pq of Pow n,R.1 These two (?) loss of power scrams were caused by momentary interruptions of electrical power to the building due to an electrical storms.

EL1EaLLElM lll This scram 15 not required by Technical Specifications. The scram occurs if power level e*ceeds 1.0 MW without adequate coolant fles (approx. 550 gam) in the primary coolant loop. This scram will also occur when adequate secondary cooling (approx. 900 gpm) is not available and power is groater than 1.0 MW.

Two (2) scrams occurred due to the operator /oper ator t rainee f alling to establish Primary Coolant flow before Increasing power level above 1 MW.

One (1) of these scrams occurred due to difficulties in maintaining secondary flow while starting up the secondary system in the winter line-up. The cooling tower is drained over night and 1t is not refilled until it is needed.

Start up while "he tower is filling sometimes leads to the introduction of air slugs into the coolant loop.

An air slug in the secondary coolant system will allow the secondary flow switch to trip the sccandary pump which in turn trips l

the primary pump, and this will cause a scram if the power level is greater than 1.0 MW.

4 LQw Water tevel (2)

These scrams occurred due to accidental actuation of the Back-Up tow level Scram while the Back-Up Float Switch for the 3 gpm Hak e-Up/ECCS was being inspected. There are separate micro switches to actuate the Low Level Scram and the 3 9pm Make-Up/ECCS, but both are activated by the same float. The first one of these occurred due to the ficat being jostled during inspection. The second occurred due to a dropped screwdriver striking the switch housing.

IV. Maintenqntqa It is estimated that about 520 hours0.00602 days <br />0.144 hours <br />8.597884e-4 weeks <br />1.9786e-4 months <br /> (10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per week) were spent on maintenance-related activities. Only 140 of these hours are reflected in the Summary of Operations.

These hours account for time when normally scheduled activities could not be carried out due to the need to make necessary repairs to the reactor system or for that time when the reactor was schedules to perf orm survoillance activities. The sigmfic?at items of maintenance are given below.

Auxiliary Coolina SYStent;, The pump motor for the Auxiliary Cooling System Pump failed. This motor ran almost continuously for 30 years. An exact replacement for it was not available. The pump and motor were both replaced. The replacement pump is fabricated from stainless steel as aluminum pumps are not available except as special orderL, 1he performance characteristits of the new pump and motor exceed those of the old pump and motor.

Cmttcle Recorder Inkinn SYit&mi The inking Systems for the tin, ar and tog N Channels were replaced. The replacement syr, tem uses replaceable ink Lartridges.

The oid inking systems relied on capillary action to keep the ink flowing onto the chart paper. The old system required a lot of attention to keep the ink flowing and of ten too much ink flowed, creating a mess. The new system does not rely on ink reservoirs and several feet of capillary tubing so there is less likelihood cf the tubing becoming f ouled with the recorder drive cords, and there are no ink spills to clean up. Performance of the new system is superior.

Console Fev Switch: Several wafers on the Conaole Key Switch were replaced because they appeared worn. Switch inspection and replacement is part of an on-going attempt to reduce electronic noise in the control panel circuitry.

Intrusion Systar!u The battery pack for the Intrusion System was replaced because of its inability to keep the alarm relay energized. This battery pack had been in use for several years.

Radiation Monitorina System: 1ho Tracerlab Area Radiation Monitoring ( ARH)

System failed several times during the year. This system is over thirty years clo and is tube powered. One failure was the result of a failed resistor in the high Voltage power supply. The other failures were the result of failed transistors and/or capacitors in the individual ARM units. Presently there are nine functioning ARMS in the facility; three are required by Technical Specifications for operation, i

__--m

^^^ -"

1 5

Gut.ilutMLA1LRO112f1 T he Alartn circuit of the Cont inuous Air Monitor (CAM) failed due to a shorted f i li, e r capacitor. When this circuit fails. It causes the buildirig exhaust air to be directed to a charcoal filter bank before it exits the building.

V.

Con;illions Urder $11mJdd9_qL1LEBM There was ono 50.59 review car ried out during 1990 r elated to the system descr iption and operations as described in the Safety Analysis Report. This 50.59 teview dealt with Squaremave operntion above 1.0 MW and below 0.3 HW.

This 50.59 review of Squarewave operation came about because of a distrapancy that has existed between the TRIG /. Operating Procedures and the TRIGA Safety Analysis Report since operations beg 6n in 1969. Due to the nature of th)s situation, a copy of the 50.59 review and a historical review of this discr epancy is attached to this annual report.

Three e>per iment s were t ev10wed and appr oved during 1990 under the conditions of 100FR50.59. Iwo of these esperiments involve Nuclear Pumped Laser research and one involves evaluation of radiation effects on the dielectric characterictics of electrical insulators.

The two laser experirnents r eviewed and approved in 1990 are continuations of previously performed experiments. Both experiments require the placement of laser cells adjacent to the TRIGA core in the Thru Beam Port. The laser cells are evacuated and ther filled with the gas of interest for the esperiment. The TRIGA is then pulsed. The typical pulse size is t 3.00. One experiment looks for direct lasing of the gas in the cell while the looks f or indirect lasing.

Hazards associated with these laser experiments are radiological. There are two radiological hazards associated with these type of experiments. One is the activation of the later carriage. The other is the production of radioactive gases inside t he lar,er cells.

Doobure f rom the laser carriage is minimized by selection of structural material and handling practices. These carriages are f abricated f rom aluminum and additional components which may be used edded to the carriago, such as valves for the vacuum system are usually shiehid with flex-boron.

Additional controls, such as specif ying a minimum waiting time be handling the carriage f urther reduce exposures f rom the carriage. Bot h calculations and experience indicate that this type of carriage can be used with minimal exposures to the experimerters. This type laser carriage has been used with this type of laser experiment for twenty-five years.

Control of radioactive gases f or these experiments is accomplished through the use of the following as appropriate, cold trap, hold up volume and charcoal filters, The cases evacuated f r on the laser cell pass through the cold tr ap and 3

then to the holding tank. The volume of the holding tank is large (3 ft) 3 compar ed to the largest laser cell (0.09 f t ). The gases are then allowed to decny and after a suitabl3 t irne period, released through the charcoal filters and into the building exhaust stack through a bank of absolute filters.

No

4 6

significant exposures or releases to the environment could result f rom the failure of either of these systems.

The experiment.which is performed to evaluate radiation ef fects on the dielectric charactaristics of electrical insulators involves the placement of I

a test cell (a resonant cavity) in the Thru Beam Port adjacent to the THIGA i

core. The TRIGA is pulsed and the experimenters look for changes in the resonant f requency of the cavity during the pulse. The hazard with this experirnent is also i

radiological. The same precautions taken with the laser carriages are taken with the test cell including the use of flex-boron. Sample change out is accomplished after a suitable waiting time to allow for decay of copper and alurainum isotopes.

Other precautions involve the use of portable shielding and tools with long handles.

VI.

Release of Rad.Laaglive Materials Argon-41:

Average-concentration to environs via exhaust:

9.7 E-8 uCi/ral Total release: 3.128 mci Monthly range 94-465 mci l

Tritium:

Estimation of 3,0 mci release from the evaporation of water in the reactor tank. This is based on the measured concentration of H-3 and water usage for the year.

Effluent =(t,anitary sewer): tess than 10 uCi (approx. 8.0 uCi) of beta-gamma f

emitting material was released with an average concentration of 9.4 E-7 uC1/ml.

VII. Environmental Survevg__

There were no environmental surveys performed in 1990 other than routine radiological monitoring.

Contamination surveys are performed regularly in the

}

Nuclear Reactor Laboratory. See Section VIII.

VIII. Personnel Radiation Exnosure and Sur_y_evs Within_the Fagility A. Personnel Exoosure Twenty-nine persons _were assigned film badges at the facility. Five

~

were full time employees, while tho' others averaged less than twenty hours per week in-the facility. The badges are sent to R.S. tandauer of Glenwood Illinois for-processing. -' The table below gives the whole body deep dose equivalent received by those who were assigned film badges during 1990.

Dose Eaujvalent (REMS)

Mmber of Individuals

-No Heasurable Exposure 2

j 0.01-0.10 22 0.10-0.25 5

l Above 0.25

__Q Total 29

...a.-

• ~

7 The highest indhidual dose equivalent was 250 mill 1 rems. This was receiveJ by the Reactor Health Physicist, who handles most of the samples which at e removed f rom the reactor core. Five other individuals received a dose couivalent above 100 millirems. All of these individuals received this dose equivalent as a result of handling radioisotopes and/or special experimental apparatus. All doses received by students not assigned film tadges and visitors are recorded on self-reading dosimeters and were less than 10 millirens each.

LCont hmination Surveys Emear samples from various locations around the laboratory are taken at periodic intervals. The removable contamination is determined by counting the smears with a gas flow proportional counter.

The maximum gross beta contamination is usually found in the vicinity eere

-the irradiated sumple containers are handled. There were 3,810 samples irradiated during the year.-In the samnle_ area the contamination varied f rom-approximately 100-40,000 dpm/100 cm' or 4.5 E-07 to 1.8 E-4 uCi/cm'. In the control room area 2

2 the maximum was 160 dpm/100 cm or 7.2 E-07 uCi/cm. Smears from other areas of 2

the labctet.ory showed a maximum of 5,000 dpm/100 cm or 2.3 E-05 uCi/cm?. Cloan 2

ur of these ateas always results in levels of less than-1000 dpm/100-cm or 4.5 E-6 uC1/cm'. Surveys for alpha contamination were less than 15 dpm/iO0cm or 2

6.8 E-8 uC1/cm'.

IX.

htgitar Reactor Committeg Dr. George H. Miley continued as Chairman of the Nuclear Reactor Committee for the 1990-1991 academic year.

Dr. Miley is a Professor of. Nuclear Engineering. He is the former Chairman of the Nuclear Engineering Program from the mid - 1970's through the mid 1980's and has served on the Nuclear Reactor Committee previously. "1e following members remain-' on the Nuclear _ Reactor Committee: Dr. John G. 71111ams, Associate Professor of Nuclear Engineering; Dr.

Sheldon Landsberger Associaire Professor of Nuclear Engineering; Dr. Abderrafi Ougouag, Assistant Professor of Nuclear Engineering; Mr. Hector Handel, Campus Radiation Safety Of ficer; Mr. Craig Pohlod, Reactor Supervisor (ex-of ficio); __Hr. -

Mark Kaczor, Reactor Health Physicist (ex-officio). All are previous members of this comittee except for Mr. Kaczor.

Mr. Mark Kaczor was hired as Reactor Health Physicist to replace Mr. Netl Barss, who left the University of Illinois to take a position with the U.S.

Department of. Ener0y. Mr. Kaczor was previously employed by Illinois Power Company. Mr. Kaczor has a strong background in nuclear - power plant health physics.

1

l e

HISTORICAL INFORMATION ABOUT SQUARE-WAVE OPERATION The following information relative to Square-wave Operation is the result of conversations with Mr. Gerald P.

Beck and Mr.

Jerry Logan of General Atomics.

Mr. Beck is the previous Reactor Supervisor and the Principal Author of the Advanced TRIGA Safety Analysis Report (SAR). Mr.

Logan has been an engineer with General Atomics predating the i

Advanced TRIGA SAR.

Mr. Beck indicated that he wrote the description of Square-wave Operations (Section VII.B. SJ, STEM DESIGN in the SAR) f rom some i

materials provided by General Atomics. He also stated that at the time he wrote the SAR (mid 1967), he was unfami1iar with Square-wave Operation. Mr. Beck felt he had correctly described Square-wave Operation, although he dtw, not remember discussing it with anyone from General Atomics.

Mr. Logan indicated that no Range Switch Interlock such as the one described in the SAR was ever incorporated in a'iy TRIGA. Mr.

Logan also said that he knew of no reason why Square-wave Operation should not be allowed below 300 kW or above 1.0 Mw as long as adequate core cooling was available.

?

Mr. Beck also stated that after the cooling system design was evaluated, it was suggested that the maximum Steady State Power requested in the license should be increased to 1.5 MW. He does not recall if this suggestion was made by the University of Illinois or by General Atomics. He does recall that it was made well ofter the SAR was completed. He also believes that 1.0 MW should have been changed to 1.5 MW wh6n the SAR was revised in January 1911.

Mr. Beck indicated that it was his understanding that once the Technical Specifications were approved, the SAR ceased to exist as I

a living document. He indicated this was part of an agreement between Headquarters USAEC/USNRC and the Nuclear Engineering Program. He further suggeste d that a review of the USAEC/USNRC Inspection Reports from the early 1970's might reveal some useful information on this topic, e, search for these reports is currently in progress.

1 l

The Square-wave Section of the Reactor Start-up and Operation Procedure is virtually unchanged since -the early 1970's. This-section describes Square-wave Operations up to 1.5 MW. The only lim 1tation on Square-wave Operation is that the Forced Cooling

- System must be in operation prior to Square-wave Operation above 1.5 MW.

l 1

i e

y y

.-.p w

r -. - - -. -

wr-e-

.e-em--

r-e.-r--%

er

.s---.-r,w,--

i e..

G.

UN:\\'ERSITY OF ILLINOIS

50. 59 ret'!EW OF THE TRIGA SQUARE-WA\\'E PROCEDURES 1.

Does thia change to the TRIGA Square-wave Procedures constitute a change to the Advanced TRIGA Reactor as described

- the TRIGA Safety Analysis Report (SAR)?

Yes.Section VII.B.i EQdes of ODeration and Control of the SAR describes Square-wave Operation as limited to power levels between 0.3 and 1.0 MW.

The change allows Square-wave Operation to any power up to the maximum Steady Stato limit of 1.5 MW.

Section VII.B.1.b.

Sagare-wave Ooeration describes an interlock which prevents initiation of a Square-wave unless the RANGE SWITCH is on the 1 MW Range. This interlock does not exist. Consultation with Ceneral Atomics revealed that such an interlock has not been part of any TRIGA.

2.

Does the change to the TRIGA Square-wave Procedures consti tute a change to the procedures as described in the TRIGA SAR?

Yes.Section VII.B.1.b

$sgaro-wave Ooeration of the SAR describes Square-wave Operation as 11m1ted to power levels Detween 0.3 and 1.0 MW.

The change allows Square-wave Operation to any power up to the maximum Steady State limit of 1.5 MW.

3.

Does this change to the TRIGA Square-wave Procedures involve tests or experiments not described in the TRIGA SAR?

Yes, but only as pertains to Square-wave Operations below 0.3 MW and between 1.0 MW and 1.5 MW.

4.

Does this change to the TRIGA Square-wave Procedures involve a change to the TRIGA Technical Specifica tions for opera tlon?

No. Square-wave Mode of operation is defined in the Technical Specifications as f ollows: "1. 9 Smiare-wave Hoce - The reactor is in Square-wave Mode when the Reactor Mode Select 1on Switch is in the Square-wave position. In th's mode, the reactor power is increased on periods less thare one second, is held at constant power by automatic motion of the control rods, and is then reduced by shutting the reactor down.

f

.The only other specific reference to Sq'Jare-wave Operation in the Technical Specifications appears in Section 3.4 Reactor l

Instrumentation. In this section it is specified that there must be a minimum of two operable Reactor Power Level measuring cha,1nels.

I t

l l

4 y

.g.

S.

Does the change tc the TRIGA Square-wave Procedures involve

}

an unreviewed safet.v question as defined in 10CFR 60.59(a)(2)?

(1) The change to the Square-wave Procedures does not increase the probability of occurrence o r_

the consequences of an accident or malfunction of equipment important to safety previously evaluated in the SAR.

(ii) The change to the Souare-wav# Procedures does not create the possibility for an accicent or malfunction of a different type than any evaluated previously in the SAR.

(iii) The change to the Souaro-wave Procedure does not reduce the margin of safety as defined in the basis for any technical specification.

For Steady State Operation above 1.0 MW, it is necessary to establish Primary and Secondary System coolant flow first.

Failure to establish Primary and Secondary System coolant flow or loss of _ Primary or Secondhry coolant flow with power level above 1.0 MW will result in a Loss of Flow Scram.

Since Square-wave Mode is a suecialized type of Steady State Operation, it is also necessary for Primary and Secondary System coolant flow to be established if power level is to exceed 1.0 MW.

The Loss of Cooling Scram ensures that adequate cooling is availabio for operation above 1.0 MW. The Linear Power Scram provides protection against over p.

er operation that could lead to exceeding Fuel Temperature limitations (1.5 MW Range) and ensures that the TRIGA is shut down if power exceeds the j_

selected Range setting for Linear Power.

This ensures a positive indication of oower level prior to Square-wave Operation. These scrams are functional in the Steady _ State

-Mode, Automatic Mode and Square-wave Mode of Operation.

An interlock'.prevants insertion.of transients if the pc-ar level is greater than 250 kW (presently set to.i kW). This interlock is functional in all modes of operation.

The TRIGA is_ approved for_ reactivity transients up to $4.60.

A reactivity addition of this size will not result in Fuel lL Temperature exceeding.its safety limit,- even 1f the Insertion is made with an initial power of 250 kW.

j I

A Square-wave to 1.5MW requires the - initial adddition of approximately

$1.00 of reactivity.

Addition of

$1.00 of reactivity v1a pulsing from low power would result in a peak power of approximately 1.8 MW.

If the pulsing rod fails to drop a steady state power of approximately 185 kW would result. This transient is much less severe than the one which

a..

. would result from the $4.00 pulso permitted by Technicci Specifications.

A Square-wave to 300 kW requires

't h e initini addition of approximately 30.70 of reactivity.

Addition of 10.70 of reactivity via pulsing from low power would result in a peak power of approximately 550 kW and a steady state power of eporoximately 125 kW.

Reictivity loss for 1.5 MW operation is appioximately $ 3. f> 0 (with flow). Reactivity loss for 300 kW io approximately $1.45 (without flow).

n Squaro-wave operation bridges the gap between Steady State Operation and Pulsing Operation. The aspects of Square-wave Operation which reflect Steady State Operation have been reviewed and are subject to the same limitations which apply to Steady State Operation.

The aspects of Scuare-wave Operation which reflect Pulsing Operation have been reviewed and are subject to the same limitations which apply to Pulsing Operation.

No safety significance exists relative to Square-wave Operation below 300 kW. No saf ety significance exists relative to Square-wave Operation between 1.0 MW and 1.5 MW.

M I

/ThO Date Prepared by:

/ I M el d ate 8

Reviewed by:

+

/

,6