ML20245G850

Forwards Armed Forces Radiobiology Research Institute Triga MARK-F Reactor Facility Annual Rept 1988. Revised Pages 3-39,3-43,4-22,4-23 & 4-24 of SAR Also Encl

ML20245G850
Person / Time
Site:	Armed Forces Radiobiology Research Institute
Issue date:	03/29/1989
From:	Irving G DEFENSE, DEPT. OF, DEFENSE NUCLEAR AGENCY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20245G854	List: ML20245G850 ML20245G878
References
NUDOCS 8905030249
Download: ML20245G850 (6)

Text

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'DEFEN5E NUCLEAR AGENCY ARMED FORCES RADIOBIOLOGY RESEARCH INSTITUTE BETHESDA, MARYLAND 20814 5145 a

AFtutI/DIR 29 March 19H9 i

l SU BJ i:CT Annual Report for the Armed Forces Ra<t i ob io l og y Research I ns L i tu t.e 's TRIGA Reactor, hicense R-84, Docket. 50-170 ini .t - . o .,n e ; n . r p ; ii i . . .umn.-- o ri :; s:oo ; i s, m :, m . i ,ni, ,. +

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h e ac t o f- at tho Armed forces R ad i o b i o l o g ,s Research InstiLolo.

Triis re po r t is s u bm i t. t.ed in ac co rdance w i t.h reiin t rotnorit s f oiimi i :-

the reactor Technical Specifications ( l. i ce n se R-84, Do"kot 50-170 Section 6.6. Also enclosed are ( ooies of Lne pages in the faciiiLy Sa fe Ly Analysis Repo r t (SAR) L na t. were changed based on 10 CFR 50.59 safely analyses. These pages are 3-39, 3-13, 4-22. 1-23 and 4-24 and represent a one for one replacement for exi5 Ling SAR pages, ploase (ontact either Mr. Mark Moore (202) 295-1290, or me at (202) 295-1210 if you have any questions o r commen t.s concernirg the ra po r t.

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GEORGE IRVING, iI Colone1, USAF, BSC Director 1icensee, R-84 Cf: Regional Administrator, Region I USNRC Inspector (Mr. Williams)

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cycle, logarithmic, strip-chart recorder mounted on the CAM itself. The units have a sensitivity range of 50 cpm to 50 x 103 cpn and a nminal accuracy of +10 percent.

The units have a time constant which is inversely proportional to the count rate, being 200 seconds at 50 cpn and l

1 second at 50,000 cpn. We units have the capability of actuating alarms at two adjustable radiation levels. ,

%e primary reactor room CAM is located in the southwest corner of the reactor room and is visible frm Rom 3156. The air sampled by this CAM is taken from approximately 18 inches above the reactor pool surface inside the core support structure. The air is passed through a hose to the CAM. The air is exhausted by the CAM back to the reactor room. The primary reactor room CAM forms an integral part of the reactor room containment capability, in that when the primary CAM high-level alarm is ,

activated, the supply and exhaust dampers to the reactor room in the ventilation system are automatically closed to isolate the reactor rom air volume.

The backup reactor rom CAM is located along the west wall of the reactor rom and is visible from the control room and Rom 3158. We air sampled by this CAM is taken directly frm above the warm drain located along the east side of the reactor pool. The air is exhausted by the backup CAM back to the reactor room.

A description of the CAM's alarms, locations and read-out is given in Table 3-2 and Figures 3-12 through 3-14. We alarm setpoints can be found in the appropriate AFRRI internal document.4 Additionally, CWy1 a

flashing visual light on the reactor auxiliary instrumentation console in j the reactor control room will 'be illuminated when the priinary reactor room CAM is set in the TEST roode during testing.

3.6.3 Stack Monitoring Systems The stack monitoring systems consist of the stack flow monitor, the stack particulate monitor, and the stack gas tronitor. These systems provide data about the radioactive effluents discharged through the AFRRI stack.

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Table 3-3. We radiation alarm setpoints can be found in the appropriate AFRRI internal documents.4 3.6.3.3 Stack Gas Monitoring System The stack gas nonitor (SGM) system is a NaI scintillation detection systs which samples exhaust air frm the reactor stack. The air is passed through a filter to remove particulate before being analyzed.

This systs will detect those effluents which have been released into the reactor stack, and reports the average Ar41 concentration at the sample point every six hours on a printout. An hourly report of the Ar41 concentration for the previous 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> is printed at the end of each day.

We stack gas monitor system is capable of activating alarms at two levels. . Additionally, a flash mg visual light on the reactor auxiliary CkagtA instrumentation console in the reactor control rom will be illuminated If O'CU when the stack gas mmitoring system low count warning is activated or when the stack gas monitoring system pump motor is turned off. The i location of the systen readouts and alarms are illustrated in Table 3-3. (

. The setpoints for the radiation alarms can be found in the appropriate AERRI internal documents.

3.6.4 _P_e_rimeter Monitoring j A perimeter nonitoring program is conducted by AFRRI primarily to l 1 measure environmental doses re ived from dionuclides produced by the AFRRI-TRIGA reactor, particularly Ar41 However, significant anounts of other gama-emitting radimuclides generated by all the radiation sources at AFRRI are also measured.

The perimeter mmitoring system ccnsists of a large ntrnber of j stations, each equipped with a thernolumin scent dosimeter (TLD), which detects X-ray and ganma radiation from 1 mR to 1,000 R. The TID has a mini-n detectable dose generally below that produced by background i radiation. Fading of the TID is not significant for the exposure periods used. I l

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4.11 REACKR INSTRUMENI'ATION he AERI-TRIGA reactor core is monitored by a variety of detectors.

One thernoccuple frm each of the two instrumented fuel ele.ents emprise two of the detectors. A fission detector, two or nore ion chambers, and a cerenkov detector emprise the remaining reactor detectors. These < Mil I detectors are utilized to provide at least five independent ' channels' which $ 0u.@

monitor the pwer level and fuel temperature of the core during steady state operation and at least three independent ' channels' which nonitor the pwer level and fuel temperature of the core during pulse operations." A

" channel" is the cmbination of a detector, interconnecting cables or lines, amplifiers, and output device (s) which measure a specific variable. The six channels utilized in the AFRRI-TRIGA reactor include: the multirange linear '

channel, the wide-range log channel, high flux safety channel one, high flux safety channel two, and fuel temperature safety channels one and two. Some of these channels, in addition to having readouts on the reactor console, form part of the reactor scram logic circuitry, and the system of rod withdrawal prevent interlocks.

4.11.1 Multirange Linear Channel The multirange linear channel reports reactor pwer frm source level

( 10 3 thermal watts) to full steady state power (1 MWt). The output of the fission detecter, fed through a preamplifier, serves as the channel input.

We multirange linear channel consists of two circuits: the count rate circuit, and the campbelling circuit. For power levels less than 1 kilowatt (t), as celected on the pwer range select switch, the count rate circuit is utilized. The count rate circuit generates an output voltage proportional to the number of pulses or counts received frm the fission detector. Hence, the output is proportional to the neutron population and tha reactor power level. For steady state pwer levels at or above 1 kilowatt (t), as selected on the power range select switch, the campbelling 4-22 1

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circuit is utilized. The campbelling circuit generates an output voltage proportional to the reactor power level by a verified technique of noise envelope amplitude detection and measurement. known as campbelling. The output from the appropriate circuit is fed to an amplifier which supplies a signal to the strip chart recorder located on the reactor console. We power level is scaled on the strip chart recorder or indicated on a digital voltmeter for precise reading between 0 and 100 percent of the power indicated by the power range selected switch on the console. The digital b W ISDec89 voltmeter is connected into the test points on the linear amplifier circuit provided by the manufacturer for the purpose of measuring the output of the multi-range linear channel. The strip chart records the output for all steady state modes of operation but not during pulse operation.

4.11.2 Wide-Range Icq Channel The wide-range log channel also measures reactor power fran source level

( 10 3 thermal watts) to full steady state power (1MWt). The circuitry of this channel is very similar to that of the multirange linear channel. The preamplifier output of the same fission detector feeding the multirange linear channel is also fed into the count rate and campbelling circuits of the wide-range log channel. The outputs of these two circuits are log amplified and then sumed in a summing amplifier. We suming amplifier supplies a signal to the strip chart recorder located on the reactor console. The power level is indicated on a 104ecade log scale (10 3 watts (t) to 1 MW(t)). The strip chart records this output for all steady state mades of operation but not during pulse operation.

During certain steady state modes, the wide-range log channel also measures the rate of change of the power level, which is displayed on the period / log meter located on the reactor console.

%e wide-range log channel forms part of the rod withdrawal prevent interlock system. The channel activates variable set point bistable trips 4-23 I

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in the rod withdrawal prevent interlock system (Section 4.12) if source level neutrons ( 10 3 thermal watts (t)) are not present, if the reactor power level is above 1 kilowatt (t) when switching to the pulse mode, if a steady state power increase has a period of 3 seconds or faster during certain steady state modes, or if high voltage is not supplied to the fission detector.

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4. '.1. 3 High Flux Safety Channels One and Two '

High flux safety channels one and two report the reactor power level as measured by. independent power monitors (ion chambers or Cerenkov detector) placed above the core.

High flux safety channels one and two are independent of one another but operate in identical manners during steady state operation. Each channel l

consists of an ion chamber placed above the core and the associated q .A electronic circuitry. The steady state power level, as measured by the two sr o u. 6 high flux safety channels, is displayed on two separate meters located on I the reactor console.

During pulse operation, high flux safety channel one is shunted and the sensor for high flux safety channel two is switched to a third, independent detector. High flux safety channel two measures the peak power level during the pulse (NV channel). The NV channel output is displayed on the strip chart recorder located on the reactor console. The NVT channel output is displayed on the reactor console NVT meter, q Knobs for each channel, located on the reactor console, allow the channels to be checked for calibration. Switching these knobs to any node from operate (i.e., to the zero or calibrate positions) causes an immediate reactor scram. Ioss of high voltage to any of the ion chambers also causes an immediate reactor scram.

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