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{{#Wiki_filter:U USGS science for a changing world Department of the Interior US Geological Survey PO Box 25046 MS 974 Denver, CO 80225-0046 October 31, 2011 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555  
{{#Wiki_filter:U USGS science for a changing world Department of the Interior US Geological Survey PO Box 25046 MS 974 Denver, CO 80225-0046 October 31, 2011 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555


==Reference:==
==Reference:==
U.S. Geological Survey TRIGA Reactor (GSTR), Docket 50-274, License R-1 13 Request for Additional Information (RAI) dated September 29, 2010


U.S. Geological Survey TRIGA Reactor (GSTR), Docket 50-274, License R-1 13 Request for Additional Information (RAI) dated September 29, 2010
==Subject:==
Response to Question 6 of the Referenced RAI Mr. Wertz:
Question 6: NUREG 1537, Part 1 Section 4.3, "Reactor Tank or Pool," requests a description of the reactor tank and associated components. The description should include design considerations ensuring that no hydrodynamic, hydrostatic, mechanical, chemical, and radiation forces or stresses could cause a failures and should also discuss the locations of penetrations and attachment methods for other components and pipes. The GSTR SAR provides only physicaldimensions. Please describe the design of the reactor tank including any penetrations.
Response: Design details of the GSTR reactor tank (liner) were provided in our response to RAI Question 1, dated August 30, 2011. This same response provides details of the attachment of the reactor core structure to the tank bottom. All power instrument detectors, fuel storage racks, the water skimmer, the fuel inspection tool and sample holders are attached by bolting to the top lip of the reactor tank. The 6" vertical pump tube is attached to the tank wall by aluminum straps that were welded to the tank wall during the tank construction. There are 5 of these aluminum attachment straps, spaced at approximate vertical intervals of five feet and each strap is 1 inch wide and 0.125" thick. Cooling and purification piping are not attached to the tank.
The only penetration in the reactor tank (liner) is the vertical pump tube. This tube is 6 inches diameter for the top 20 feet 3inches, and 3inches diameter for the bottom 4 feet 9 inches. This tube penetrates the tank bottom, providing access to the bottom annulus, between the bottom of the tank liner and the original reactor tank bottom. This access is needed to check for possible water accumulation. An eductor pump is available to insert into the pump tube if it is needed to remove water from the annulus. The tube penetration through the aluminum bottom was made during the tank construction and it is sealed by welding the aluminum tube to the bottom. The pump tube is normally plugged at the top with a shield plug that contains both neutron and gamma shielding.


==Subject:==
Update on neutronic/thermal hydraulic analyses-The MCNP model for the existing core is done and the control rod worths have been benchmarked successfully. Another benchmarking to get the shape of the control rod worth curves to match the existing core data is being worked on now. We expect to have answers for all neutronics questions on the existing core configuration after this control rod worth curve benchmarking is successfully completed. A goal of November 23 has been set to have all of the MCNP analyses done on the limiting core configuration. This will result in most of questions 8-11 and 15.1 to be answered in the response submitted by November 30.
Response to Question 6 of the Referenced RAI Mr. Wertz: Question 6: NUREG 1537, Part 1 Section 4.3, "Reactor Tank or Pool," requests a description of the reactor tank and associated components.
The RELAP model and associated analyses will require more time due to extensive input data needed and the computer codes requiring long run times to converge to accurate results. It is hoped that the final questions (mainly question 12) can be answered by January 14; however this date may vary since we have no experience in performing these coupled neutronics/thermal hydraulics analyses. These analyses will be performed for both steady state and transient conditions.
The description should include design considerations ensuring that no hydrodynamic, hydrostatic, mechanical, chemical, and radiation forces or stresses could cause a failures and should also discuss the locations of penetrations and attachment methods for other components and pipes. The GSTR SAR provides only physicaldimensions.
Sincerely,
Please describe the design of the reactor tank including any penetrations.
(/
Response:
Tim DeBey USGS Reactor Supervisor I declare under penalty of perjury that the foregoing is true and correct.
Design details of the GSTR reactor tank (liner) were provided in our response to RAI Question 1, dated August 30, 2011. This same response provides details of the attachment of the reactor core structure to the tank bottom. All power instrument detectors, fuel storage racks, the water skimmer, the fuel inspection tool and sample holders are attached by bolting to the top lip of the reactor tank. The 6" vertical pump tube is attached to the tank wall by aluminum straps that were welded to the tank wall during the tank construction.
Executed on 10/31/11 Copy to:
There are 5 of these aluminum attachment straps, spaced at approximate vertical intervals of five feet and each strap is 1 inch wide and 0.125" thick. Cooling and purification piping are not attached to the tank.The only penetration in the reactor tank (liner) is the vertical pump tube. This tube is 6 inches diameter for the top 20 feet 3inches, and 3inches diameter for the bottom 4 feet 9 inches. This tube penetrates the tank bottom, providing access to the bottom annulus, between the bottom of the tank liner and the original reactor tank bottom. This access is needed to check for possible water accumulation.
Betty Adrian, Reactor Administrator, MS 975 USGS Reactor Operations Committee}}
An eductor pump is available to insert into the pump tube if it is needed to remove water from the annulus. The tube penetration through the aluminum bottom was made during the tank construction and it is sealed by welding the aluminum tube to the bottom. The pump tube is normally plugged at the top with a shield plug that contains both neutron and gamma shielding.
Update on neutronic/thermal hydraulic analyses-The MCNP model for the existing core is done and the control rod worths have been benchmarked successfully.
Another benchmarking to get the shape of the control rod worth curves to match the existing core data is being worked on now. We expect to have answers for all neutronics questions on the existing core configuration after this control rod worth curve benchmarking is successfully completed.
A goal of November 23 has been set to have all of the MCNP analyses done on the limiting core configuration.
This will result in most of questions 8-11 and 15.1 to be answered in the response submitted by November 30.The RELAP model and associated analyses will require more time due to extensive input data needed and the computer codes requiring long run times to converge to accurate results. It is hoped that the final questions (mainly question 12) can be answered by January 14; however this date may vary since we have no experience in performing these coupled neutronics/thermal hydraulics analyses.
These analyses will be performed for both steady state and transient conditions.
Sincerely, (/Tim DeBey USGS Reactor Supervisor I declare under penalty of perjury that the foregoing is true and correct.Executed on 10/31/11 Copy to: Betty Adrian, Reactor Administrator, MS 975 USGS Reactor Operations Committee}}

Latest revision as of 12:02, 12 November 2019

U.S. Geological Survey Triga Reactor (Gstr), Response to Question 6 of the Referenced RAI
ML11314A106
Person / Time
Site: U.S. Geological Survey
Issue date: 10/31/2011
From: Timothy Debey
US Dept of Interior, Geological Survey (USGS)
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML11314A106 (2)
v • d • e


Text

U USGS science for a changing world Department of the Interior US Geological Survey PO Box 25046 MS 974 Denver, CO 80225-0046 October 31, 2011 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Reference:

U.S. Geological Survey TRIGA Reactor (GSTR), Docket 50-274, License R-1 13 Request for Additional Information (RAI) dated September 29, 2010

Subject:

Response to Question 6 of the Referenced RAI Mr. Wertz:

Question 6: NUREG 1537, Part 1 Section 4.3, "Reactor Tank or Pool," requests a description of the reactor tank and associated components. The description should include design considerations ensuring that no hydrodynamic, hydrostatic, mechanical, chemical, and radiation forces or stresses could cause a failures and should also discuss the locations of penetrations and attachment methods for other components and pipes. The GSTR SAR provides only physicaldimensions. Please describe the design of the reactor tank including any penetrations.

Response: Design details of the GSTR reactor tank (liner) were provided in our response to RAI Question 1, dated August 30, 2011. This same response provides details of the attachment of the reactor core structure to the tank bottom. All power instrument detectors, fuel storage racks, the water skimmer, the fuel inspection tool and sample holders are attached by bolting to the top lip of the reactor tank. The 6" vertical pump tube is attached to the tank wall by aluminum straps that were welded to the tank wall during the tank construction. There are 5 of these aluminum attachment straps, spaced at approximate vertical intervals of five feet and each strap is 1 inch wide and 0.125" thick. Cooling and purification piping are not attached to the tank.

The only penetration in the reactor tank (liner) is the vertical pump tube. This tube is 6 inches diameter for the top 20 feet 3inches, and 3inches diameter for the bottom 4 feet 9 inches. This tube penetrates the tank bottom, providing access to the bottom annulus, between the bottom of the tank liner and the original reactor tank bottom. This access is needed to check for possible water accumulation. An eductor pump is available to insert into the pump tube if it is needed to remove water from the annulus. The tube penetration through the aluminum bottom was made during the tank construction and it is sealed by welding the aluminum tube to the bottom. The pump tube is normally plugged at the top with a shield plug that contains both neutron and gamma shielding.

Update on neutronic/thermal hydraulic analyses-The MCNP model for the existing core is done and the control rod worths have been benchmarked successfully. Another benchmarking to get the shape of the control rod worth curves to match the existing core data is being worked on now. We expect to have answers for all neutronics questions on the existing core configuration after this control rod worth curve benchmarking is successfully completed. A goal of November 23 has been set to have all of the MCNP analyses done on the limiting core configuration. This will result in most of questions 8-11 and 15.1 to be answered in the response submitted by November 30.

The RELAP model and associated analyses will require more time due to extensive input data needed and the computer codes requiring long run times to converge to accurate results. It is hoped that the final questions (mainly question 12) can be answered by January 14; however this date may vary since we have no experience in performing these coupled neutronics/thermal hydraulics analyses. These analyses will be performed for both steady state and transient conditions.

Sincerely,

(/

Tim DeBey USGS Reactor Supervisor I declare under penalty of perjury that the foregoing is true and correct.

Executed on 10/31/11 Copy to:

Betty Adrian, Reactor Administrator, MS 975 USGS Reactor Operations Committee

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