ML19263C057
| ML19263C057 | |
| Person / Time | |
|---|---|
| Site: | Neely Research Reactor |
| Issue date: | 01/23/1979 |
| From: | Marlone Davis Neely Research Reactor, ATLANTA, GA |
| To: | Desiree Davis Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7902020227 | |
| Download: ML19263C057 (4) | |
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GEORGI A INSTITUTE OF TECHNOLOGY SCHOOL OF NUCLEAR ENGINEERING ATLANTA GEORGI A 30332 F R AN K H. N E ELY NUCLE A R HESE ARCH CE NTER T E LE PHON E: (404)894-3600 January 23. 1979 U.S. Nuclear Regulatory Commission Division of Operating Reactor Washington. DC 20535 Attention: Mc D. K.
Davis, Chief Operating Branch #2 Gentlemen:
REFERENCE:
Docket 50-160 This letter answers questions raised in response to our September 13, 1978 request for modification of Appendix A to license R-97.
Paragraph I Organizational Changes The administration of the Nuclear Research Center was transferred from the Engineering Experiment Station to the School of Nuclear Engineering. The modified organization chart reflects the change in organization. There is no change in the operation staff of the reactor nor in the operation and responsibility of the Radiation Safety Office. The change in organization is not in conflict with ANS 15.8.
Paragraph II Item 2 From Appendix A to R-97 dated December 29, 1964, the GTRR operated at power levels up to 1 IW with a D20 flow set-point of 900 GPM until October 1974.
In the Mk I core (10 plate eleme would not have exceeded 3.3 (10)gt) the max 4 mum local heat flux at one MW BTU /hr-ft".
In the Mk II reference Cory (16 plate element) the maximum heat flux at one MW is % 2 (10)" BTU /hr-ft the heat transfer at these low heat fluxes is adequate to insure that the fuel temperature in the MkII core is less that that in the MK I core i.e.,
the cladding is thinner (0.010 in vs 0.020 in) and the plate is thinner (0.050 in vs 0.060 in).
Since the scram point is to be set at 1000 rather than 900 gpm the operation is more conservative than in the Mk I core.
The operation is well within the safe regime as shown in Figure II-l of the current Appendix A to R-97.
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Paragraph II Item 3 Specification 3.1.d leads to a less safe condition than is desired because the shim-safetys cannot be individually calibrated with the reactor critical. Only as a group can the reactivity of the shim-safetys in the critical reactor be measured and then only from the just critical configuration. The modification will allow a rod-interchange calibration of the controls to be performed for the re-quired periodic surveillances.
Paragraph II Item 4 This is to satisfy a request originating from I & E division of the USNRC.
The second paragraph in the basis should be changed to read: Specifications 3.1.b, 3.1.c and 3.2.e provide assurance that the core will remain sub-critical during loading changes and shim-safety blade maintenance or in-spection.
Paragraph II Item 5 Modify table 3.2 as shown on the enclosed table.
Paragraph II Item 6 It is requested that 4.la (page 28) be modified to read Shim-safety blade reactivity worths and the shutdown margin shall be measured annually and whenever a core configuration is loaded for which shim-safety blade worths have not been measured.
Paragraph II Item 6 It is preferable that the shutdown margin be measured rather than calculated siace for any safety related parameter such as shutdown a calculation is less credible than the measured result.
The ECCS system is not necessary for the 1 MW operation. Experiments at MIT (see MIT operations Memo #98 cecember 25 1965 by S. T. Brewer) and in England (see AERE-M1317 1964 by R. Panter) show that for similar fuel operating at this power level temperatures would be less than 450 C in the event of a LOCA.
Fbre details on these items will be furnished at your request.
Very truly ours, L/WW4 Monte V. Davis Director MVD:lrm
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TABLE 3.2
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SAFETY RELATED INSTRUMENTATION REQUIRED FOR OPERATION 1-I' 7
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Minirum No. Required Function
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Instrumentation Setpoint Mode 1 Mode 2
..s Linear power level measurement and 1
1 input for the automatic control Pico ammeter. channel mode I
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Alarm and prevents startup High building radiation
<10 mr/hr or 2x normal 5
SMw Background Gas monitor 1
1( )
Initiates containment isolation Filter assembly monitor 1
1(b)
Initiates containment isolation
_s.
Kanne chamber
. Initiates containment isolation 1
1 1
1(b)
Initiates containment isolation D 0 Leak detection system 2
Particulate monitor 1
1 Initiates containment isolation 2(b)
Alarm and prevents startup Emergency cooling tank level <280 gal.
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(a) Area monitors shall be located on the experimental level, the reactor top, in the reactor b5s'ement, and in an area that will be allow changes in reactor coolant radioactivity to be detected.
(b) -
4 Either channel may be bypassed for a period not to exceed 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> for test, repair or calibration.
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