ML15349A894

University of Maryland - Request for Additional Information for License Renewal Pertaining to Thermal Hydraulics

ML15349A894
Person / Time
Site:	University of Maryland
Issue date:	12/02/2015
From:	Koeth T Univ of Maryland - College Park
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC ME1592
Download: ML15349A894 (7)

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Building 090

• UNIVERS MARYLAND ITYO College Park, Maryland 20742-2115 301.4105.4952 TEL 301.405.6327 FAX 609.577.8790 CELL koeth@umd.edu GLENN L. MARTIN INSTITUTE OF TECHNOLOGY A. JAMES CLARK SCHOOL OF ENGINEERING Department of MaterialsScience & Engineering Nuclear Reactor & RadiationFacilities Timothy W. Koeth, Director December 2, 2015 Document Control Desk United States Nuclear Regulatory Commission Washington, D.C. 20555-0001

SUBJECT:

UNIVERSITY OF MARYLAND - REQUEST FOR ADDITIONAL INFORMATION FOR LICENSE RENEWAL OF THE MARYLAND UNIVERSITY TRAINING REACTOR PERTAINING TO THERMAL HYDRAULICS (TAC NO. MEl1592)

LICENSE NO. 70; DOCKET NO. 50-166 Enclosed please find enclosed the response to the RAI dated September 10, 2015 for the University of Maryland Training Reactor (MUTR), License No. R-70; Docket No. 50-166.

I declare under penalty of perjury that this response is true and correct.

T oh* . 2Regards,

• .

• eth, Assistant Research Professor and Director University of Maryland Training Reactor & Radiation Facilities 74o30

Response to Request for Additional Information Facility Operating License No. R-70 The Maryland University Training Reactor Dockett No. 50-166 la. Fuel element type The drawing shown below should serve to identify the Fuel Type lb. Fuel Dimensions The drawing shown below provides detailed dimensions of the MUTR Fuel elements

ic. Fuel Cluster Adapters The drawing shown below provides dimensions of the four-rod fuel clusters including the top and bottom adapters The drawing below shows the fuel element spacing within the four rod fuel cluster.

i. Fuel cluster (4) Bottom grid plate adapter The drawing shown belowprovides more detailed dimensions for the lower grid plate adapter of the four-rod fuel clusters The drawing shown below provides a close-up of the bottom grid plate adapter.

ii. Top FE Stainless Steel Locking Plate The drawing below shows the top locking plate dimensions and close-up detail. The flow area can be calculated by using known dimensions and an image analysis software.

iii. Fuel cluster (4) top handle The drawing below gives dimension details of the top handle of the four-rod fuel clusters.

id. Thermal Hydraulics and Neutronic Calculations Thermal hydraulic and Neutronic calculations are not particularly relevant or safety significant when applied to the MUTR as a result of its low operating power and temperature. However, do to the potential consequences of high peaking factors and nucleate boiling, however unlikely, the MUTR staff intends to develop the knowledge and expertise to model the reactor core and provide simulations and calculations relating to thermal hydraulics and neutronics. To accomplish this, it is necessary to gain experience in both MCNP and TRACE codes. The initial steps have already been taken to acquire these codes and the plan moving forward is as follows:

December 2015 Obtain MCNP and TRACE codes January -June 2016 Obtain training and experience for MCNP code June - December 2016 Model MUTR Core in MCNP January-June 2017 Obtain training and experience for TRACE code June - December 2017 Perform thermal hydraulic & neutronics calculations January -June 2018 Prepare report of core analysis This proposed plan is subject to change as the MUTR staff learns more about the codes and the calculations that need to be performed through the course of the project. If any official submissions to the NRC are required 6 to 24 months, depending on the complexity of the requirements, should be included in the time estimated in addition to the schedule shown above.

le. Grid Plate Distance from bottom of the tank to the bottom of the fuel elements The top point of the fuel elements sits at an elevation of approximately 50 inches from the bottom of the reactor tank. Given a nominal fuel element length (tip to tip) of 29.875 inches, the bottom elevation of the fuel elements is approximately 20.125 inches from the bottom of the reactor tank ii. Grid plate holes that do not contain fuel are open or closed?

The grid plate holes that do not contain fuel, detectors, the start-up source, reflectors or the pneumatic irradiation port are open to flow during normal operation iii. Other flow channels There are no other penetrations in the core to allow coolant flow other than the FE adaptor in the grid plate.

iv. Grid spacing dimensions The grid spacing is 3.189" in the east-west direction and 3.035" in the north-south direction as shown by the drawing below.

"GRID PLATE ADAPTER if. Flow Rate The typical flow rate of the reactor coolant is by natural convection. The numbers quoting 120 gpm

• pertain to the primary water system which is not required to be used continuously during reactor operations and therefore should not be included in thermal hydraulic calculations.