ML20217K881

Corrected First Page of Safety Evaluation Supporting Amend 44 to License R-28,changing Date in First Paragraph to 970930 & Date in Second Paragraph to Oct 1996

ML20217K881
Person / Time
Site:	University of Michigan
Issue date:	04/23/1998
From:	NRC (Affiliation Not Assigned)
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ML20217K866	List: ML20217K861 ML20217K881
References
NUDOCS 9805040184
Download: ML20217K881 (1)

Text

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, s* g NUCLEAR REGULATORY COMMISSION 2 WASHINGTON, D.C. 20655-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 44 TO FACILITY OPERATING LICENSE NO. R-28 UNIVERSITY OF MICHIGAN DOCKET NO. 50-2

1.0 INTRODUCTION

By letter dated April 2,1998, the University of Michigan (licensee) submitted proposed changes to the Ford Nuclear Reactor Technical Specifications (TSs) to add a reactor pool coolant inlet temperature rundown for the control rods, if the inlet temperature equals 114*F in the forced convection mode. The licensee also modified the TSs to include in Table 3.1 a pool tempera-ture rundown at a pool temperature equating 129*F, which already exists as a Limiting Safety System Setting (LSSS) in the Natural Convection Mode (see existing TSs 2.2.2.1).

2.0 EVALUATION The licensee has added, as a TS requirement, an automatic rundown of the control rods if the pool inlet temperature equals 114*F and the thermal power level is greater than 1.6 Mw. The ,

actualinstallation of this rundown feature took place on September 30,1997, and was i approved by the Safety Review Committee.

This rundown was added because it was discovered in October 1996 that the automatic rundown of the pool outlet temperature, with an LSSS set at 129*F, may not assure that the t inlet temperature Safety Limit (SL) of 116*F would be met if the coolant rate through the

( reactor was increased. The possibility of this happening was observed when the nominal l coolant ficw was increased from 990 gallons per minute (gpm) to 1180 gpm. It was noted that i the outlet temperature was 126.2*F and the inlet temperature was 114.8*F. Thus, the inlet temperature was 1.2*F from the SL while the outlet temperature was 2.8*F from the automatic l rundown. The licensee took care of this situation on an interim basis by lowering the outlet temperature rundown to 126*F, but later decided to install an automatic rundown on the inlet temperature and set it at 114*F, which is 2*F below the SL of 116*F to allow for measurement errors.  !

The staff finds that the inlet temperature safety channel rundown provides automatic protective action to prevent exceeding the 2 Mw reactor coolant inlet temperature SL of 116*F under all anticipated operating conditions, and finds it acceptable. ,

l The licensee also added, in Table 3.1 of the TS (page 13), a pool temperature rundown to be l activated at a pool temperature of 129*F when the reactor is opersted in the natural cunvection flow mode. This rundown already exists since an LSSS in the natural convection mode of 9005040184 900423 ENCIOSURE PDR ADOCK 05000002 P PDR  :