ML043410136
| ML043410136 | |
| Person / Time | |
|---|---|
| Site: | U.S. Geological Survey |
| Issue date: | 12/07/2004 |
| From: | Alexander Adams NRC/NRR/DRIP/RNRP |
| To: | Day W US Dept of Interior, Geological Survey (USGS) |
| Adams A, NRC/N RR/DRIP/RNRP, 415-1127 | |
| References | |
| TAC MC5120 | |
| Download: ML043410136 (5) | |
Text
December 7, 2004 Mr. Warren Day, Reactor Administrator United States Department of the Interior Geological Survey Box 25046, MS 974 Denver Federal Center Denver, CO 80225-0046
SUBJECT:
UNITED STATES GEOLOGICAL SURVEY REQUEST FOR ADDITIONAL INFORMATION RE: USE OF ALUMINUM CLAD FUEL (TAC NO. MC5120)
Dear Mr. Day:
We are continuing our review of changes to the technical specifications (TSs) for the United States Geological Survey TRIGA Research Reactor which you submitted on November 16, 2004. During our review of your TSs changes, questions have arisen for which we require additional information and clarification. Please provide responses to the enclosed request for additional information within 60 days of the date of this letter. In accordance with 10 CFR 50.30(b), your response must be executed in a signed original under oath or affirmation.
Following receipt of the additional information, we will continue our evaluation of your TSs changes.
If you have any questions regarding this review, please contact me at (301) 415-1127.
Sincerely,
/RA/
Alexander Adams, Jr., Senior Project Manager Research and Test Reactors Section New, Research and Test Reactors Program Division of Regulatory Improvement Programs Office of Nuclear Reactor Regulation Docket No. 50-274
Enclosure:
As stated cc w/enclosure: See next page
December 7, 2004 Mr. Warren Day, Reactor Administrator United States Department of the Interior Geological Survey Box 25046, MS 974 Denver Federal Center Denver, CO 80225-0046
SUBJECT:
UNITED STATES GEOLOGICAL SURVEY REQUEST FOR ADDITIONAL INFORMATION RE: USE OF ALUMINUM CLAD FUEL (TAC NO. MC5120)
Dear Mr. Day:
We are continuing our review of changes to the technical specifications (TSs) for the United States Geological Survey TRIGA Research Reactor which you submitted on November 16, 2004. During our review of your TSs changes, questions have arisen for which we require additional information and clarification. Please provide responses to the enclosed request for additional information within 60 days of the date of this letter. In accordance with 10 CFR 50.30(b), your response must be executed in a signed original under oath or affirmation.
Following receipt of the additional information, we will continue our evaluation of your TSs changes.
If you have any questions regarding this review, please contact me at (301) 415-1127.
Sincerely,
/RA/
Alexander Adams, Jr., Senior Project Manager Research and Test Reactors Section New, Research and Test Reactors Program Division of Regulatory Improvement Programs Office of Nuclear Reactor Regulation Docket No. 50-274
Enclosure:
As stated cc w/enclosure: See next page DISTRIBUTION:
PUBLIC RNRP/R&TR r/f TDragoun MMendonca AAdams WBeckner OGC EHylton FGillespie CBassett DMatthews WEresian SHolmes Isaac GHill (2) PDoyle DHughes PMadden KWitt PYoung ADAMS ACCESSION NO.: ML043410136 TEMPLATE No.: NRR-106 OFFICE RNRP:PM RNRP:LA RNRP:SC NAME AAdams EHylton PMadden DATE 12/ 7/04 12/ 6 /04 12/ 7/04 C = COVER E = COVER & ENCLOSURE N = NO COPY OFFICIAL RECORD COPY
REQUEST FOR ADDITIONAL INFORMATION UNITED STATES GEOLOGICAL SURVEY DOCKET NO. 50-264
- 1. The regulations in 10 CFR 50.30(b) require requests for license amendments to be made under oath or affirmation. Please resubmit your entire application (including original cover letter) with a new cover letter under oath or affirmation.
- 2. Technical specification (TS) D.1. contains a limit on calculated steady state power level of any fuel element of 22 kW. The purpose of this limit was to ensure that the departure from nucleate boiling ratio at the hottest point in the reactor fuel would not fall below two, an acceptable safe condition. Your proposed changes to the TS apply this limit only to stainless steel fuel elements. Why is this limit not applicable to all fuel, including aluminum clad fuel placed in the core? If this limit is not applicable to the aluminum clad fuel, what power limit per fuel element is applicable for the aluminum clad fuel? Please revise your proposed TS appropriately.
- 3. Proposed TS D.3. discusses limiting measured fuel temperature in an aluminum clad element to 530 EC. This 530 EC temperature limit for aluminum clad fuel is the safety limit based on preventing the phase change in low hydride TRIGA fuel. The safety limit temperature is normally not used as the measured temperature limit because uncertainty in making the measurement results in needing to use a lower value. It appears that you do not possess the ability to measure the temperature in aluminum clad fuel elements.
Even if you did measure the fuel temperature, fuel temperature is not an input into the reactor safety system that would result in a scram.
The reactor safety system protects the integrity of the fuel cladding by initiating a scram if Safety Channel 1 or 2 exceeds 110 percent of full power. There is also a TS requirement that the reactor not be operated in a manner which would cause the measured fuel temperature to exceed 800 EC. Exceeding this limit does not result in any automatic action. Explain how the high power scram set point (1.1 MW) will prevent aluminum clad fuel elements from exceeding a temperature of 530 EC in the F and G rings. Does limiting the temperature of the thermocouple fuel element in the B or C ring to 800 EC provide additional protection of the aluminum clad fuel safety limit? Please revise your proposed TS appropriately.
- 4. Your application presents data on fuel temperature measurements in reactors. For measurements from the USGS reactor, where in the core was the thermocouple fuel element located?
- 5. Your application states that the maximum fuel temperature of stainless steel clad elements in the G ring of the reactor is approximately 180 EC. Please explain how this value was determined. What would the value be in the F ring?
- 6. Your application quotes data from GA showing that 3.08$ pulses did not produce fuel temperatures over 500 EC. Please provide a reference for this data.
- 7. Will transverse bend and longitudinal elongation measurements be made on the aluminum clad fuel received from VA before the fuel is placed into service? If so, what were the results of the measurements? If not, how will you ensure that the fuel meets the proposed TS requirements?
- 8. You have proposed measuring transverse bend and longitudinal elongation every 60 months. Because this is a new fuel type please consider a requirement to measure approximately 20 percent of the aluminum clad fuel annually. In addition, if any of the aluminum clad fuel exceeded the measurement limits, all aluminum clad fuel in the core would be checked. This would allow potential generic problems to be detected early, create a pool of data on aluminum clad fuel performance and result in a 60-month inspection schedule after the fourth year. The inspection schedule based on pulses would remain unchanged.
- 9. The accident analysis in the SAR for the USGS reactor discusses loss of reactor pool water. The analysis concludes that the maximum temperature reached in the core is 780 EC. While within the safety limit for stainless steel clad fuel, this temperature is greater than the safety limit for aluminum clad fuel. However, this analysis is for the hottest fuel element in the core. Please provide an analysis of the maximum temperature reached by a aluminum clad fuel element in the F and G ring following a loss of reactor pool water.
- 10. The accident analysis in the SAR for the USGS reactor discusses a reactivity accident where 3.00$ of reactivity is added to the reactor operating at a steady state power level of 1.4 MW. The results show a peak fuel temperature of 804 EC. While within the safety limit for stainless steel clad fuel, this temperature is greater than the safety limit for aluminum clad fuel. However, this analysis is for the hottest fuel element in the core.
Please provide an analysis of the maximum temperature reached by a aluminum clad fuel element in the F and G ring following a reactivity addition at power.
- 11. Controlling pH in addition to conductivity is important to prevent corrosion in systems with aluminum at elevated temperatures such as found on the surface of operating fuel elements. Information is available about corrosion protection of aluminum systems (see, for example, Handbook of Power Plant Chemistry, Hans-Gunter Heitmann, CRC Press, Boca Raton, 1993 or Criteria for Corrosion Protection of Aluminum-Clad Spent Nuclear Fuel in Interim Wet Storage, James P. Howell, Westinghouse Savannah River Company, WSRC-MS-99-00601). Controlling pH in the 5.5 to 7.5 range will minimize uniform corrosion. Please discuss the need to control pH in addition to conductivity and propose changes to TS C.2 as needed.