ML102110049

University of Maryland Responses Request for Additional Information Regarding the License Renewal for Maryland University Training Reactor

ML102110049
Person / Time
Site:	University of Maryland
Issue date:	07/28/2010
From:	Al-Sheikhly M Univ of Maryland
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC ME1592
Download: ML102110049 (9)

Text

UNIVERSITY OF Building 090 College Park, Maryland 20742-2115

• MARYLAND GLENN L. MARTIN INSTITUTE OF TECHNOLOGY 301.405.5207 TEL 301.314.2029 FAX www.mse.umd.edu A. JAMES CLARK SCHOOL OF ENGINEERING Departmentof Matenals Science andE*tnneering July 28, 2010 Document Control Desk United States Nuclear Regulatory Commission Washington, D.C. 20555-0001

Reference:

University of Maryland, Request for Additional Information Regarding the License Renewal for the Maryland University Training Reactor, Docket No. 50-166, License No. R-70 (TAC NO. ME 1592)

Enclosed are the University of Maryland's responses to technical RAIsl and 3-5 presented in the NRC's April 6, 2010 Request for Additional Information.

The University's response to technical RAI 2 depends on the progress of the Idaho National Lab. The University will submit that response to the NRC as soon as possible after we receive it. We anticipate that will be sometime before the end of August.

If there are questions about the information submitted, please write to me at:

Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 or email me at mohamad@umd.edu. I would appreciate it if you would copy Prof. Robert Briber on any such correspondence: Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115; rbriberpumd.edu.

I declare under penalty of perjury that the foregoing responses are true and correct.

Sincerely,

/6)

Mohamad Al-Sheikhly Professor and Director Maryland University Training Reactor Enclosure cc: Robert Briber 4OcQO

OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR ADDITIONAL INFORMATION UNIVERSITY OF MARYLAND, MARYLAND UNIVERSITY TRAINING REACTOR, LICENSE NO. R-70DOCKETNO. 50-166 The U.S. Nuclear Regulatory Commission (NRC) staff is continuing the review of your application for renewal of Facility Operating License No. R-70, dated May 12, 2000, Safety Analysis Reportfor the Maryland University Training Reactor (2000 SAR). During our review, questions have arisen for which we require additional information and clarification. Our review conformed to the Interim Staff Guidance on the Streamlined Review Process for Research Reactors, NUREG-1537, Part 1, NUREG-1537, Part 2 and Title 10 of the Code of FederalRegulations (10 CFR). Please address and provide the requested information to the following:

NRC RAI #1:

"Requirements for limiting conditions for operations are addressed in 10 CFR Section 50.36(c)(2).

NUREG-1537, Part 1, Section 4.5.3 Operating Limits provides an acceptable way of meeting the 10 CFR Section 50.36(c)(2) requirements by establishing a shutdown margin with the most reactive control rod withdrawn from any operating conditions. Chapter 4, Section 4.5.3 of the 2000 SAR provides a discussion indicating that the shutdown margin is $0.9 with the core at maximum excess reactivity of

$3.5 and most reactive control rod Shim IIwithdrawn. Please identify the steps leading to the $0.9 value with the two control rods inserted having $2.3 and $2.7 reactivity worths."

Response: The shutdown margin specified in the license submittal (90 C)was apparently a misinterpretation of the method used to calculate the value.

Based on control rod calibrations and data from reactor operation, the calculated cold critical condition reactivity is $6.40. With the highest worth rod (Shim 2: $2.88) in the full out position, the reactor shutdown margin is $3.52 with no experiments in place. Technical Specifications require shutdown margin to be greater than $0.50 and, therefore, a maximum of $3.02 is available for experiments.

The Technical Specification limit on experiments is $3.00. However, at the critical position, the excess reactivity is $1.30, and the Technical Specifications limits the excess reactivity to $3.50, which means, under this limit, the maximum experimental worth is $2.20. This is more restrictive than the $3.00 experimental Technical Specification limit.

Assuming the excess reactivity experimental limit of $2.20, the shutdown margin is $1.32, which is $0.82 greater than the $0.50 minimum required.

UMD Responses to NRC Technical RAIs of April 6, 2010 July 28, 2010 Page 2 of 8 NRC RAI #3:

"According to 10 CFR Section 20.1301 (a) (1) the total effective dose equivalent (TEDE) to individual members of the public from the licensed operation cannot exceed 0.1 rem (1 mSv) in a year. Section 11.1.1.1 of the 2000 SAR estimated that in a typical operation year the total Ar-41 release would be 100 mCi. In your response to RAI 46 dated September 4, 2004 University of Maryland estimated that the occupational dose from the argon-41 (Ar-41) release would be 177 mrem. Please discuss the potential maximum dose consequences to the maximally exposed member of the public, due to potential release of Ar-41 from the facility and discuss whether it is in compliance with 10 CFR Section 20.1301(a)(1)."

Response

Compliance with 10 CFR 20.1301(a)(1) due to potential release of Ar-41 from the facility, can be achieved through the use of the COMPLY code with the following parameters:

• Release rate of Ar-41 in Ci/yr = 0.1 Ci/yr [2000 SAR Section 11.1.1.1 Airborne Radiation Sources];

• Release Height of 7 meters [Building height which is equal to the louver height on the ceiling of the Reactor Building];

• Building Height of 7 meters [2000 SAR Section 3.1 design criteria];

• There are 2 stacks on the roof of the building;

• Distance to receptor is 8 meters and is located directly outside of the building;

• Building width of 14 meters [2000 SAR Section 3.1 design criteria];

• Default mean wind speed used: 2.0 m/s.

The effective dose equivalent is shown to be 0.1 mrem/year. Refer to the report, Attachment 1 to this document, using the COMPLY Code run with these parameters.

NRC RAI #4:

"According to 10 CFR Section 20.1201 (a) the occupational dose limits for adults, the total effective dose equivalent to an adult may not exceed 5.0 rems (0.5 Sv). Section 13.2.1 of the 2000 SAR discusses the Maximum Hypothetical Accident (MHA) providing dose consequences to the member of the public in compliance with 10 CFR Section 20.1301 'Dose limits for individual members of the public.' Please discuss the potential maximum dose consequences to an adult due to the MHA considering the facility evacuation plan and whether it is in compliance with 10 CFR Section 20.1201(a).

Response

The potential Maximum Dose Consequences are based on the following assumptions:

1. The adult is an occupational worker in the reactor at the time of the MHA;

2. All activity is released instantaneously to the volume of the reactor facility;

UMD Responses to NRC Technical RAIs of April 6, 2010 July 28, 2010 Page 3 of 8

3. All ventilation systems fail - however, the most conservative approach assumes no ventilation and therefore no removal constant based on air flow out and into the reactor building;

4. No decay assumptions are made during the MHA;

5. Regulatory Guide 1.4 C.2 is applied as acceptable assumptions for dose conversions;

6. The MHA is defined in 13.2.1 of the SAR;

7. Regulations regarding 10 CFR 20.1201(a) states:

a) The licensee shall control the occupational dose to individual adults, except for planned special exposures under § 20.1206, to the following dose limits.

(1) An annual limit, which is the more limiting of--

(i) The total effective dose equivalent being equal to 5 rems (0.05 Sv); or (ii) The sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue other than the lens of the eye being equal to 50 reins (0.5 Sv).

(2) The annual limits to the lens of the eye, to the skin of the whole body, and to the skin of the extremities, which are:

(i) A lens dose equivalent of 15 rems (0.15 Sv), and (ii) A shallow-dose equivalent of 50 rem (0.5 Sv) to the skin of the whole body or to the skin of any extremity.

8. The inventory calculated is released inside the reactor proper - then doses due toexternal submersion in a cloud as well as intake due to iodine, strontium and cesium isotopes is calculated. The TEDE = DDE + CEDE; where DDE is the deep dose equivalent, and CEDE is the committed effective dose equivalent. The dose limits are calculated to determine the effective dose to an adult evacuating the reactor in the event of an MHA.

9. Longest route traveled to evacuate the building 69 ft;

10. Walking speed of 4.0.mph [2.73 ft/sec] requires an evacuation time of 25 seconds;

11. Running speed of 6.0 mph [4.1 ft/sec] requires an evacuation time of 17 seconds; The next section presents the specific condition of 10 CFR 20.1201, the calculated potential dose and compliance with the applicable dose limit.

Condition of 20.1201 (a) (1) (i)

TEDE = DDE + CEDE

• DDE = Dose rate from infinite cloud with the receptor at the site of the cloud. The concentration should be the activity divided by the volume in the reactor space.

The DDE dose rate = Dy =.0.507 EY, avg X [rad/s] , where Xis the concentration [Ci/m 3] x the average gamma energy.

At a conservative evacuation time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, the DDE is 16.9 mrem.

= CEDE = internal dose from inhalation of fission products and the iodine isotopes - in this case the iodine activity from Table 13.2, and the Strontium and Cesium isotope activities from Table

UMD Responses to NRCTechnical RAIs of April 6, 2010 July 28, 2010 Page 4 of 8 13.3 can be used to calculate intake and the subsequent dose equivalents using the ALl for each isotope. Intake [Ci] = Br [0.02 m3/min] x C [Ci/m 3] x t [walking/running].

CDE organ = Intake [Ci]x 50 Rem/ALI [Ci]

The CEDE is symbolized by HEso = I WT HT.S0 where w, is the tissue weighting factor for organs and HT.so is the Committed Dose Equivalent CDE, the 50 year dose from an intake.

At a conservative evacuation time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, the CEDE is 348.7 mrem COMPLIANCE ACHIEVED: At a conservative evacuation time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, the TEDE [TEDE = DDE +

CEDE] is 365.6 mrem.

Condition of 20.1201 (a) (1) (ii)

DDE + CDE (organ or tissue) < 50 Rem - organ dose such as the thyroid; The DDE is determined as above and any attenuation by tissues can be taken into account; the CDE is determined from intake. and the ALl for the organs of interest..

COMPLIANCE ACHIEVED: At a conservative evacuation time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, the DDE and CDE is 11.6 Rem.

Condition of 20.1201 (a) (2) (i)

LDE at 300 mg/cm2 < 15 Rem, LDE is a lens dose equivalent at that depth, (DDE is at 1000 mg/cm 2) 3 c The beta dose rate to the lens of the eye: Db,eye 2.45 X 10-7 C Eavg euB,tx° mGy/h

• The beta ray absorption coefficient in tissue, UB,t = 18.6(Em -0.036)-1' 37 cm 2/g C = concentration in [Bq/m 3 ]

E = average beta energy COMPLIANCE ACHIEVED: At a conservative evacuation time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, the LDE is 0.21 mrem.

Condition of 20.1201 (a) (2) (ii)

SDE at 7 mg/cm 2 < 50 Rem , SDE is the shallow dose equivalent at that depth.

The beta dose rate to the skin Db, skin = 2.45 X10-7 C Eavg eUB,tx 0°°7 mGy/h COMPLIANCE ACHIEVED: At a conservative evacuation time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, the SDE is 0.874 mrem.

UMD Responses to NRC Technical RAIs of April 6, 2010 July 28, 2010 Page 5 of 8 NRC RAI #5:

According to 10 CFR Section 20.1301(a)(1), the total effective dose equivalent to individual members of the public from the licensed operation cannot exceed 0.1 rem (1 mSv) in a year. Section 13.2.3 of the 2000 SAR states that in a complete loss of coolant accident the dose rate at any point outside the biological shield would be less than 1.2 rem/hr at 1 hr after shutdown, and less than 31 mrem/hr at 8 hr after shutdown. Please provide accumulated dose results to the closest member of the public after a complete loss of pool water for the period of the hypothetical loss of coolant accident and indicate whether it is in compliance with 10 CFR Section 20.1301 (for example, at the perimeter of the rear parking lot, where the facility has a high-bay door providing no shielding to the outside).

Response

Given the data provided in Section 13.2.3 of the 2000 SAR, the dose rate at any point outside the biological shield would be less than 1.2 rem/hr at 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> after shut down and less than 31 mrem/hr at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after the shutdown. Using these stated values, and providing for no attenuation due to the roll-up bay door, the dose rate at the exterior perimeter fence, where a member of the public could be present, would be lessthan 17.5 mrem/hr at 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> after shut down and less than 0.5 mrem/hr, 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after shut down. These calculations utilize a distance of 8.28 meters, which is the shortest distance from the north side point of the biological shield through the roll-up door to the exterior fence line. Based upon these calculated dose rates and the response to the loss of coolant water scenario, the accumulated dose to a member of the public, present at the fence line, shall be less than 100 mrem, in compliance with the public dose limits cited in 10 CFR 20.1301.

UMD Responses to NRC Technical RAIs of April 6, 2010 July 28, 2010 Page 6 of 8 ATTACHMENT 1 COMPLY: VI.6. 7/21/2010 5:39 40 CFR Part 61 National Emission Standards for Hazardous Air Pollutants REPORT ON COMPLIANCE WITH THE CLEAN AIR ACT LIMITS FOR RADIONUCLIDE EMISSIONS FROM THE COMPLY CODE - V1.6.

Prepared by:

University of Maryland College Park Radiation Facilities UMCP Chemicaland Nuclear Engineering Mary Dorman 301-314-8336 Prepared for:

U.S. Environmental Protection Agency Office of Radiation and Indoor Air Washington, DC 20460

UMD Responses to NRC Technical RAIs of April 6, 2010 July 28, 2010 Page 7 of 8 COMPLY: Vl.6. 7/21/2010 5:39 Public Dose Compliance with Ar-41 UMTR SCREENING LEVEL 2 DATA ENTERED:

RELEASE RATES FOR STACK 1.

Release Rate Nuclide (curies/YEAR)

AR-41 5.OOOE-02 RELEASE RATES FOR STACK 2.

Release Rate Nuclide (curies/YEAR)

AR-41 5.OOE-02 SITE DATA FOR STACK 1.

Release height 7 meters.

Building height 7 meters.

The source and receptor are not on the same building.

Distance from the source to the receptor is 8 meters.

Building width 14 meters.

SITE DATA FOR STACK '2.

Release height 7 meters.

Building height 7 meters.

The source and receptor are not on the same building.

Distance from the source to the receptor is 8 meters.

Building width 14 meters.

UMD Responses to NRCTechnical RAIs of April 6, 2010 July 28, 2010 Page 8 of 8 Default mean wind speed used (2.0 m/sec)

COMPLY: Vl.6. 7/21/2010 5:39 NOTES:

Input parameters outside the "normal" range:

None.

RESULTS:

Effective dose equivalent: 0.1 mrem/yr.

• • • Comply at level 2.

This facility is in COMPLIANCE.

It may or may not be EXEMPT from reporting to the EPA.

You may contact your regional EPA office for more information.

END OF COMPLIANCE REPORT **********