ML20148H870
| ML20148H870 | |
| Person / Time | |
|---|---|
| Site: | Rhode Island Atomic Energy Commission |
| Issue date: | 06/06/1997 |
| From: | Tehan T RHODE ISLAND, STATE OF |
| To: | Mendonca M NRC (Affiliation Not Assigned) |
| References | |
| NUDOCS 9706130011 | |
| Download: ML20148H870 (4) | |
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l STATE OF RHODE ISLAND AND PROVIDENCE PLANTATIONS !
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l .) h. l RHODE ISLAND ATOMIC ENERGY COMMISSION l Nuclear Science Center South Ferry Road l Narragansett, R.I. 02082-1197 ;
June 6, 1997 Docket No. 50-193 Mr. Marvin Mendonca, Senior Project Manager ;
Non-Power Reactors, Decommissioning and l l Environmental Project Directorate Division of Reactor Projects - III/IV/V ,
U.S. Nuclear Regulatory Commission
_l Washington, D.C. 20555 '
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Dear Mr. Mendonca:
I This letter concerns a request for an amendment of the RIAEC license by I changes to the Technical Specifications. Inconsistencies were discovered concerning the RINSC safety limits, limiting safety limit settings, and the Safety Analysis Report. The RINSC staff has completed a thorough review of the Technical Specifications, Safety Analysis Report, and industry standards l and requests the following changes.
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- 1. page 12 Section 2.1.1 Safety Limits in the Forced Cony. Mode )
i FROM: Reactor Thermal Power, P Reactor Coolant Flow through the Care, m Reactor Coolant Inlet Temperature, Ti Height of Water Above the Top of the Core, H l l
TO: Reactor Thermal Power, P j Reactor Coolant Flow through the Core, m '
Reactor Coolant Outlet Temperature, To l Haight of Water Above the Top of the Core, H FROM: 1. The true value of reactor pc wer (P) shall not exceed 2.4 MW and the true value of flow (m) shall not be less than 1580 gpm.
l 2. The true value of reactor coolant inlet temperature (Ti) at power levels up to 2 MW shall not exceed 1150F,
- 3. The true value of the reactor coolant outlet temperature shall not exceed 1250F.
- 4. The true valt.e of water height above the active core (H) shall not be less than 23.54 feet while the reactor is operating at any power level. !
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To: 1. The true value of reactor power (P) shall not exceed 2.4.MW.
- 2. The true value of reactor coolant flow (m) shall not be-less
.than 1580 gpm.
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- 3. The true value of reactor coolant outlet temperature (To) shall not exceed 1250F.
- 4. The true value of water height above the top of the core (H) shall not be less than 23.54 feet while the reactor is operating at-any power level.
Basis for Change: The RINSC discovered that the above mentioned Technical Specification had included both reactor coolant inlet and outlet temperature as safety limits. Currently, the RINSC only has automatic action (scram) for the outlet temperature. The RINSC has investigated these limits and determined that the use of either inlet or outlet temperature provides sufficient protection to the reactor fuel. ANSI /ANS-15.1-1990 states that an important process variable to monitor is either reactor coolant inlet or outlet triperature due to the fact that these two temperatures are coupled thermally based on power and flow. l The RINSC agrees and also believes that the outlet temperature is a better representation of the actual coolant temperature exiting the core and therefore more ;
- j. conservative. Additionally, the thermal hydraulic analysis j l (Part B of the SAR) shows that with the proposed safety E
limits for forced convection (power, coolant flow, pool level, and coolant outlet temperature) fuel clad temperature limits will not be exceeded. The analysis does not evaluate reactor coolant inlet temperature, but rather reactor j' coolant outlet temperature (Part B, Table B of the SAR),
l coolant flow, and power level. Finally, inquiries were made to other similar research reactors and the results showed that approximately 50% (MIT, RINSC) have outlet temperature safety limits while the other 50% (UVA, Lowell, Mich) have inlet temperature safety limits.
- 2. page 13 Section 2.1.1 Safety Limits in the Forced Cony. Mode From: Bases:
The basis f or - forced convection safety limits is that the ;
calculated maximum cladding temperature in the hot channel of the l
) most compact core will not be exceeded. The inlet temperature
, shall apply to all power levels up to the 2 MW licensed power
- level. The thermal hydraulic analysis (Part B, of the SAR) shows l-
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that.with this inlet temperature, the outlet temperature will not j exceed the outlet temperature scram setting technical specification at the safety limit of 2.4 MW.
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To: Bases:
The basis for forced convection . safety limits .is that the calculated maximum cladding temperature in the hot channel of the L most compact core will not be exceeded. The thermal ~ hydraulic l- analysis (Part B of the SAR) shows that if the safety limits are not exceeded the coolant will not reach the onset of nucleate boiling even at the safety limit of 2.4 MW. Additionally, the limit on coolant outlet temperature will prevent exceeding the-temperature limit for the cleanup system resin.
Basis for Change: The current bases states that with the referenced inlet temperature, the outlet temperature scram setpoint will not
- be reached. However, after further investigation, the SAR
!. states that with an inlet temperature.of 108.140F at 2.MW I
and 1715 gpm flow, .the outlet temperature would be 122.450F. The outlet temperature scram is set <= 1210F.
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The change to the bases is a clarification from the SAR and the addition of the cleanup system. resin temperature limit.
l- 3. page 14 section 2.2.1 Limiting Hafety system settings (F.C.)
'FROM: Specification:
The . limiting safety system settings for reactor thermal power (P), primary coolant flow through the core (m), height of water above'the top of the core (H), and rcactor coolant inlet (Ti) and exit temperatures (Te) shall be as follows:
I j Parameter LSSS
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P (Max) 2.3 MW m (Min) 1600 gpm H (Min) 23.70 ft i Ti (Mar.) ll1.00F Te (Max) 121.00F TO: Specification:
The limiting safety system settings for reactor therr al
, power (P), primary coolant flow through the core (m), height j of water above the top of the core (H), and reactor coolant
- . outlet temperature (To) shall be as follows
. To (Max) 121.00F l f Basis for change: See above.
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- 4. page 22 Required Safety Channels -
Table 3.1 Add:
Reactor Reactor Safety Minimum Operating Mode System Comnonent/ channel Recuired Function in Which Recuired Pool Temperature 1 Automatic Natural Scram at Convection 1260F Basis for change: Technical Specifications Section 2.1.2 and 2.2.2, Safety Limits and LSSS, require that there be a pool temperature automatic action. The safety channel, however, was not included in Table 3.1. This addition provides consistency within the Technical Specifications.
Enclosed are the new Technical Specifications pages. If there are any questions regarding these changes, you can reach me at (401) 789-9391.
Sincerely, Lw Terry _han Dire. r i
cc: Tom Dragoun, U.S. NRC, Region 1 ,
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