ML051050259

The U.S. Geological Survey Is Herein Responding to Request for Additional Information Dated March 10, 2005. Concerns USGS Amendment Request to Research Reactor Facility License (No. R-113, Docket 50-274) to Allow Use of Aluminum Clad Triga

ML051050259
Person / Time
Site:	U.S. Geological Survey
Issue date:	04/11/2005
From:	Day W US Dept of Interior, Geological Survey (USGS)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC MC5120
Download: ML051050259 (10)

Text

USGS science fore changing world Department of the Interior US Geological Survey Box 25046 MS-974 Denver CO, 80225 April 11, 2005 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington DC 20555 Gentlemen:

The U.S. Geological Survey is herein responding to your request for additional information (TAC No. MC5120) dated March 10, 2005.

This concerns the USGS amendment request to its research reactor facility license (No. R-113, Docket 50-274) to allow the use of aluminum-clad TRIGA fuel in the core.

Correspondence concerning this response should be directed to Tim DeBey, Reactor Supervisor.

Sincerely, Warren Day Reactor Administrator I declare under penalty of perjury that the foregoing is true and correct.

kxecuted on 4/11/05 I

..A.

ADOpO

REQUEST FOR ADDITIONAL INFORMATION UNITED STATES GEOLOGICAL SURVEY DOCKET NO. 50-264

1. Your answer to question 3 of our request for additional information (RAI) dated December 7, 2004, discussed fuel temperature in the F and G rings when limiting the measured temperature of a stainless steel clad fuel element to 8000C in the B ring. Technical Specification (US) D.3 also allows the instrumented fuel element to be placed in the C ring, where fuel temperatures could be lower than in the B ring. Limiting the measured fuel temperature to 8000C in the C ring could result in higher temperatures in the F and G rings than would result from limiting measured temperature to 8000C in the B ring. Please provide maximum fuel temperatures in the F and G rings if the measured temperature of 8000C is taken from an instrumented fuel element in the C ring. (Note that your answer to question 9 below may change the 8000C temperature in this question.)

Response: In reference to question 9 of this document and our response, we are proposing to limit the measured temperature in (stainless steel) fuel elements to 7500C in the B-rng and 667 *C in the C-ring.

The table below shows the expected measured fuel temperatures in the B, C, F, and G-ings under these maximum fuel temperature conditions. As shown, the F and G-ring fuel temperatures would be 447-C and 383C, respectively. These values are below the proposed 500C fuel temperature limit for aluminum-clad fuel elements.

C-F-

B-ring ring ring F-Cooling peak B-peak C-peak ring G-ring G-medium temp ring A temp ring A temp AT peak ring A Description temp C C

T CC) C T

}°).

tempC TIC)

S.S.-

Temp limit conditions 60 750 690 667 607 447 387 383 323

2. The instrumented fuel element contains multiple thermocouples at different locations in the fuel element. Because of this, the temperature reading from the element may not be the true maximum temperature of the fuel in the element. Discuss the accuracy of your measured temperatures as compared to true temperature and the impact this has on the various temperatures given in your RAI request responses.

Response: There are several inaccuracies that can occur in the fuel temperature measurement One is electronics error from the temperature measuring instrument, an Action Pak AP4350-0003 thermocouple transmitter (see attached data sheet). This instrument has an accuracy of +0.25% of span with a cold junction compensation error of + 1C. The result would be an eror of +4.8C at 750-C.

The other error occurs from the thermocouple not being at the actual location of peak temperature in the fuel element. For steady state operations, this erroris from vertical mispositioning and it is approximately 10*C. During pulsing operations this erris 25% ofthe measured temperature. The error during pulsing is larger because it is a radial positioning eror during the rapid transient: i.e., the peak temperature occurs near the fuel cladding and not at the element centerline. For example, during pulsing operations an indicated temperature of 400"C would equal an actual peak temperature in the fuel element of 500-C.

This information is taken from Figure 111-21 of the University of Illinois SafetyAnalysis Report, dated 1969.

This figure is attached.

This potential inaccuracy impacts our response as follows: For steady state operations, it should be assumed that the peak fuel temperature is really 15C higher than indicated. Since none of the allowed I

steady state operations show that the F or G-ring temperatures are within 15*C of the 500C proposed limit (see Table in Question I response above), there is no impact to the operational safety.

During pulsing operations, the expected measured fuel temperature in the F-rng from a $3.00 pulse is 233*C. Applying the expected error of 25% plus 5C instrument error gives a true peak fuel temperature of 296@C, much less than the 500-C proposed limit. The G-ring temperature would be less, at 252VC true peak temperature (see table below). Therefore the impact of these errors on the temperatures in our previous answers is that the temperatures are still well below the safety system limit of 5000C and there is no impact to the operational safety of the GS7R.

B-ring Cooling peak B-C-ring C-F-ring F-G-nng G-medium temp ring A peak ring AT peak ring AT peak ring AT Description temp C C

T C) temp C LC)temp C CC) temp C CC)

Nominal $3 pulse -

measured temp 20 400 380 354 334 233 213 198 178 Nominal $3 pulse -peak calculated temp 20 500 480 442 422 296 271 252 227

3. What was the wt% of the fuel in the instrumented fuel element used to measure the fuel temperatures given in your responses to our RAI? If the fuel wt% of the instrumented fuel element is different than the fuel wt% of the aluminum clad fuel, explain what effect the difference in fuel wt% has on the conclusions presented in your RAI response.

Response: The instrumented fuel element used to measure the fuel temperatures in the RAI responses was a 8.5 wt%, stainless-steel clad element with a 15Flong fuel section. The aluminum-clad fuel elements are 8.0 wt% with 14"long fuel sections. This gives the aluminum-clad fuel elements -12.2%

less uranium loading than the instrumented fuel element that was used to measure the fuel temperatures.

The effect would be that the aluminum-clad fuel would generate less power per element and therefore the temperatures would be lowerthan calculated. This makes our RAI response conservative.

4. Your answer to question 3 of our RAI contains fuel temperature data based on a coolant temperature of 50"C. However, your TSs allow a bulk pool temperature up to 600C. Please present the data on fuel temperature assuming a coolant temperature of 600C.

Response: The fueltemperatures were recalculated for the condition of the coolant temperature of 600C and the results are given below. The net result is that the F and G-ring fuel temperatures increase by 5 0C.

lCooling l

F-ring F-1 Description of GSTR medium B-ring peak B-Ipeak ring AT G-ring peak ring A7 operation.

temp 0C temp 0C ring AT(rC) temp C fC temp C CC)

Normal I MWops 21 344 323 202 181 172 151

-ring at 800C 60 800 740 475 415 406 346 2

5. Your original application contained a table with a set of temperature measurements. For the 1 MW steady state measurement take in March of 2002, where was the instrumented fuel element located in the core.

Response: The March, 2002 fuel measurement supplied in the original application was taken in an instrumented element located in the C-rng (location C-5) of the GSTR.

6. Discuss the maximum fuel temperatures in the aluminum clad fuel at the reactor high power setpoint of 1.1 MW.

Response: If the GSTR was operated at 1.1 MW with the pool water temperature at 60"C, the measured fuel temperatures would be as shown in the table below. Also shown, for reference, are measured fuel temperatures at normal 1.0 MW operation.

B-ring Cooling peak B-C-ring C-F-ring F-G-ring G-medium temp ring AT peak ring AT peak ring AT peak ring AT Description temp C C

)

temp C fC) temp C CC) temp C (C)

Normal I MWops 21 344 323 305 284 202 181 172 151 Max. 1.

MWops 60 415 355 373 313 259 199 226 16 These data show that fuel temperatures in the F and G-rings are well below the proposed 5000C limit for aluminum-clad fuel. If an instrument/ocation error of 15"C for steady state operations is applied to the calculated values for 1.1 MWoperations, the F and G-ring peak temperatures are 274"C and 2410C, respectively.

7. Your answer to our RAI question 10 was based on a coolant temperature of 500C. However, your TSs allow a bulk pool temperature up to 600C. Please present the data on fuel temperature assuming a coolant temperature of 600C.

Response: This question is identical to question 4. See question 4 for our response.

8. You have proposed changes to TS D.7. It appears that your proposed wording would remove the flexibility to have a core with less than 100 fuel elements operate with a power level greater than 100 kW.

Please provide a justification for your proposed change to the TS.

Response: A historical look at the fueling of the GSTR shows that the initial fuel loading for full power operations in 1969 contained 78 fuel elements. By January 1975, the core loading had reached 101 fuel elements and it has not gone below 100 fuel elements for the last 31 years. No future requirement is seen foroperation ofthe GSTR at >100 kWwith <100 fuel elements in the core. In fact, having a small core is detrimental to the neutron flux in several of our irradiation facilities. The requirement for 100 elements or more helps to reduce the power produced by each fuel element in the core, thus limiting the peak fuel temperatures and giving a safer operation.

3

9. TS D.3. contains a fuel temperature limit of 800*C for fuel temperature. However, General Atomics in report E-117-833, 'The U-ZrHx Alloy: Its Properties and Use in TRIGA Fuel," discusses a steady-state operational fuel temperature design limit of 7500C based on consideration of irradiation-and fission-product-induced fuel growth and deformation. Please discuss.

Response: The operating history of the GSTR has been such that the existing limit of 800fC has not presented a safety threat; however, the reduction of this limit to 75(°C would be prudent and would not affect the GSTR operations. The maximum fuel temperature would occur in a B-ring element, nearest the center of the core. Because of the GSTR Technical Specification allowance for measuring fuel temperature in either the B or C ring, we are herein proposing differing maximum indicated fuel temperature limits for the two locations. The C-ing fueltemperature limit wouldneedto be lower than 75d'C in orderto assure that the maximum fuel temperature (B-ring) would not exceed 7500C.

The nominal power production in a C-ing element is 886 of the nominal power produced in a B-ring fuel element. Assuming a pool water temperature of 6(PC, a maximum fuel temperature of 75(PC in a B-ing element would correspond to a maximum fuel temperature of 6670C in a C-ring element. (see table below)

C-F-

B-ring nng ring F-G-ring Cooling peak B-peak C-peak ring peak G-medium temp ring A temp ring A temp AT (

temp ring A Description temp C C

T (CC)

C T

CC)

C T CC)

Temp limit conditions 60 750 690 667 607 447 387 383 323 As a result of this information, it is proposed to make the following revision to Technical Specification D.3: to limit the measured fuel temperature to 750 0C for B-ring measurements and 667 0C for C-ring measurements. The proposed change is given below. This proposedchange supercedes the proposed change to D.3 in our February submittal. We propose to not specify a limit on the aluminum-clad fuel in the F and G rings for two reasons: (1) the limits being imposed upon the B and C-rng fuel temperatures will inherentlyprotect the F and G ring fuel elements from exceeding 500 C, and (2) no instrumented aluminum-clad fuel elements are available to provide the associated measurements. The necessary calculations to support the safety of the aluminum-clad fuel elements in the F and G rings have been provided in the documents supporting the license amendment request.

Current wording:

D.3. Fuel temperatures near the core midplane in either the B or C ring of elements shall be continuously recorded during the pulse mode of operation using a standard thermocouple fuel element.

The thermocouple element shall be of 12 wt' uranium loading if any 12 wt* loaded elements exist in the core.

The reactor shall not be operated in a manner which would cause the measured fuel temperature to exceed 800 6c.

Proposed wording:

D.3.

Fuel temperatures near the core midplane in either the B or C ring of elements shall be continuously recorded during the pulse mode of operation using a standard thermocouple fuel element.

The thermocouple element shall be of 12 wtl uranium loading if any 12 wt* loaded elements exist in the core.

The reactor shall not be operated in a manner which would cause the measured fuel temperature to exceed 7500C in a stainless steel clad element in the B ring or 667'C in a stainless steel clad element in the C ring.

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1.0 2.0 4,0 5.0 6.0 TEMPERATURE Vs. REACTIVITY INSERTION

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-**FIGURE 11 - 21 9

XAction Pak AP4350 Isolated Thermocouple ACTION INSTRUMENTS Transmitter

• Isolates, Linearizes and Transmits

• Plug-in Input-Ranging Modules for Type J,K,T,E,R,S,B

• 1000 Volt Isolation

• Wide-Ranging Input and Output Adjustments

• Switch-Selectable Voltage/Current Outpul Ranges

• Three-Year Warranty The Action Pak AP4350 transmitter combines niany useful features in one rugged, reliable package. The AP4350 will accept a thermocouple input directly, and linearize, isolate, and transmit the equivalent temperature reading for data acquisition, Indication, or control.

Using plug-in modules, the AP4350 can be easily reconfigured In the field for any popular thermo-couple type (J, K, 7, E, R, S, B). Additionally, wide-ranging adjustments allow for virtually any input range to be accommodated. Furthermore, the output is field-selectable for a variety of ranges, both for DC voltage and current.

Input signal conditioning includes cold-junction compensation and linearization for the thermocouple input signal. Also, the input is isolated from the output up to 1000VDC or peak AC. The AP4350 combines a high-performance signal conditioner, linearizer, and isolator in a cost-effective, easy-to-.

use solution for Industrial measurement and control.

CALIBRATION The AP4350 Thermocouple Transmitter can be set for a wide variety of outputs, and the input can be adjusted for any span within the selected thermo-couple range down to 10% of the range.

Ranging modules may be changed by removing the case with four screws on the bottom. The four circuit boards can be removed from each other (see photo), and the range module'is plugged into the input board.

To set up and calibrate the AP4350, remove the top cover. First set up the output range desired using the settings In the Switch Selection Table. Next select whether calculations will be in degrees F or C, and set S4-1 accordingly (S4-1 on for 0C, off for IF).

Also set S4-2 depending on whether the minimum input value is greater than zero degrees, or positive (S4-2 on), or negative (S4-2 off).

Now calculate gain and offset from the following formulas:

TS GAIN = 100% x 10x (TH-TL)

OFFSET = 100% x Tj Where TS = effective span from Input Range Table TH = high temperature, corresponding to maximum output TL = low temperature, corresponding to minimum output.

Next set percentage offset and gain on S2 and Si, respectively, using the table below. (Note that switches are turned OFF to enable that percentage.)

POSITION l

2 l

3 4 l5 l6 7

8 OFFADDS 1

l 4 l810 l

Switch SI (offset) or S2 (gain)

All switches off = 165%

All switches on = 0%

Adjust zero and span potentiometers to set output minimum and maximum with desired Inputs TL and TH. It may be necessary to adjust the percentage up or down 1% or 2% to get exact calibration.

NOTE: Be sure to use the correct thermocouple wire and a compensated thermocouple simulator or 721-0330B

1.

N "I

calibrator, or other known thermocouple source to calibrate the AP4350.

EXAMPLE 1: We want our Type J thermocouple Input to range from 450° F to 1100° F, with a corresponding output of OV to + 10V. With the proper Type J module installed (dash 0001), we set S5-1 on and S5-2 off (voltage), and S3-1, 4 & 6 off with S4-2, 3 & 5 on (Switch Selection Table). Since we are calculating in degrees F and our offset is positive (4500 F), we set S4-1 off and S4-2 on.

Next we calculate gain and offset:

TS 1440 GAIN = 100% x lxT

-TL 100% ~lX (1040 S2 = 20% + 2% + 1% = S2-6, S2-2, S2-1 off, all others on OFFSET = 100% x -5° = -13%

S1 = 8% + 4% + 1% = S2-4, S2-3, S2-1 off, all others on

.1 I

INPUT RANGE TABLE Dash TC Nuimber Tvnn TS Input Range IAAn tAn

• - iPt x0I 8000 AF t

7 5 000

---

I 1 ux6bu bbuu AP4350-0001 J

800° C 1440° F - 80FC to+ 7500 C

-1 1 0° F to +1 320°1 F We set S2-6 off and S2-2 off with the rest of S2 positions on (20% + 2% = 22%)

OFFSET TL

=

100% x

-45

= 31%

We set S1-6 off, S1-5 off and S1-1 off with the remainder of S1 positions on (20% + 10% + 1% =

31%). We adjust zero and span so that with our 45 00 F input the output is OV, and with 11000 F input the output is 10V.

EXAMPLE 2: Output 4-2OmA, input Type T, -500C to + 1250 C (dash 0006) S5-1 off S5-2 on (current)

S3-6 off with S3-1 through S3-5 on (4-2OmA). S4-1 on (degrees C) and S4-2 off (negative offset).

-GI

=10%x 400

.=0 X400 GAIN = 100% x 1Ox (125-50) = 100% x lOX 175 100% x 4400 = 23%

-0002 J

4000 C 720° F -1 50° C to +399.9° C

-235° F to +399.90 F

-0003 K

12000C 2160°F -140°C to +1370 0C

-220e F to +25000 F

-0004 K

400°C 7200 F -1000C to +399.9° C

-150°F to +399.9°F

-0005 E

8000C 14400 F 00 to +8000C

+32°F to +14500 F

-0006 T

4000C 720° F - 800C to +399.9° C

-1 IO" F to i 399.9° F

-0007 R

160000 2880DF +3000C to +1760°C

+550° F to +32000 F

-0008 S

16000C 28800 F +300°C to +17600 C

+550° F to +32000 F

-0009 B

16000C 28800F +4000C to +18200C

, +750' F to +33000 F Switch select for degrees F.

SWITCH SELECTION TABLE Mode.

S5 1

2 3

4 5

6 1

2 2-10V ON ON ON ON ON OFF Voltage 1-5V ON ON ON F

ON OFF ON 0-10V OFF.

ON ON OFF ON OFF 0-5V OFF ON OFF ON OFF ON O-2V OFF.-

ON

.ON OFF ON ON 0-1V OFF ON OFF ON ON ON 4-2OmA ON ON ON ON ON OFF 2-10mA ON ON ON ON OFF ON Current 1-5 mA ON ON ON OFF ON ON 0-2OmA.

OFF ON ON OFF ON OFF.

OFF ON 0-10mA OFF ON OFF ON.

OFF ON 0-5 mA OFF OFF ON OFF ON ON

• 0-1 mA OFF OFF ON ON ON ON 0-l1mA may program but not recommended

CONFIGURATION SWITCH LOCATIONS Fine Span Adjust Fine Zero Adjust PF togammabl; T Output Range Switches 1

Coarse Zero (Offset) Switch ioaing Iransmlc 0anoo o

Current Switch ON en co fF p" s2 i

Offset Polarity

,a ;7l And F/C Switch

-~--- Coarse Span (Gain) Switch MAJOR COMPONENT SUBASSEMBLIES Base Assembly Input Board Plug-In Thermocouple Range Module Case Output board Switch Board Top Cover

1.

DIMENSIONS MOUNTING HARDWARE k..

APS-8 00 a (22 SLOTS 1355 Dinernions in miinwtmn inches)

I I

107 (4.21) 117 (4.61)

I

= r ts.110 (32)

TERiMINAL SCREW

-290 e

03 cm )

s

-yp.

F ~

i ~ ~ iCHANNiEL 2',

TRACK C1

)1 50mm Length)

'730 D

enn sions in millimtose (Inch'")

(292 Ho 4-D ose B reckeS A nuiIbIe.

i SPECIFICATIONS Inputs Wide-ranging inputs and outputs, field-selectable via top accessed DIP switches and potentiometers.

Ten to one adjustability/turn down range. Plug in modules for thermocouple Input types J,K,TE,R,S,B.

Outputs Field-rangeable: 0-10V, 2-10V, 0-5V, 1-5V, 0-1V, 4-2OmA, 0-1GmA.

Voltage Outputs: 10mA drive capability.

Current Outputs: 10V compliance capability.

Accuracy

• 0.25% of span.

Noise and Ripple 0.1% of span, rms.

Response Time 200mSec typical.

ORDERING INFORMATION Model No.

Description AP4350-OOOX Transmitter with ranging module (see table).

Stability Zero: +/- (0.02%/aC plus 2.pV/ 0 C).

Span: t 0.01%/"C.

CJC Error i 1"C, typical.

Conversion Time 50OmSec.

Common Mode Rejection 120dB, DC-6OHz.

Power 110V + 15% AC; 5GHz -400Hz. 4W Max.

Environmental 00 C to +60C C.

Isolation Input to output, or either Input or output to power line: 1000V DC or peak AC.

Burnout Open thermocouple detect: goes to minus overrange.

How To Order Specify AP4350-OOOX according to the 4-digit dash number from the Input Range Table. To order modules separately, specify V042 and the desired 4-digit dash number V042-OOOX.

Ranging modules may be ordered separately (ranging module required for operation).

V042-OOOX Extra ranging module (see table) to change transmitter range.

Action Instruments, Inc.

8601 Aero Drive San Diego, CA 92123 USA TWX: 910-335-2030 (619) 279-5726 Data Sheet 721-0330B Printed In USA May 1986 Action Instruments Europe, Inc.

St. James Works St. Pancras. Chichester P0194NN, West Sussex, England TLX: 869331 ACTION G Telephone: (0243) 774022 ACTION INSTRUMENTS