ML20215G353
| ML20215G353 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 10/15/1986 |
| From: | Fiedler P GENERAL PUBLIC UTILITIES CORP. |
| To: | Zwolinski J Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8610200328 | |
| Download: ML20215G353 (5) | |
Text
_ - _ - _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
e GPU Nuclear Corporation NUDIM[
10o Interpace Parkway Parsippany. New Jersey 07054-1149 (201)263 6500 TELEX 136-482 Wnter's Direct Dial Number:
October 15, 1986 Mr. John A. Zwolinski, Chief Operating Reactors Branch No. 5 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Zwolinski:
Oyster Creek Nuclear Generating Station (0CNGS)
Docket No. 50-219 License No. DPR-16 Maximum Drywell Temperature lupplemental Information With your letter of November 22, 1985, you requested supplemental information to GPU Nuclear's letter of August 1,1985, which submitted Topical Report 5024, " Evaluation to Increase Normal Drywell Temperature Operating Limit".
Your request included the following items:
1.
The Appendix A Technical Specifications (TS) for Oyster Creek do not have limiting conditions for operation or Surveillance requirements on the maximum allowable drywell temperature.
Either propose the appropriate technical specification or provide the justification for not needing these TS before the restart from Cycle 11 refueling outage; 2.
Provide the alcorithm for detennining the drywell bulk temperature and a justification for the algorithm, or propose a TS for the drywell peak temperature; and 3.
Provide the evaluation on the aging effects of the 150*F drywell bulk temperature on the electrical equipment environmentally qualified under 10 CFR Part 50.49.
ge f*
s\\
8610200328 861015 N b' ht. 0*
PDR ADOCK C5000219 P
PDR O
4P g
GPU Nucleur Corpc ation is a subsniiary of GeneralPubhc Utihties Corporation
1
. Drywell Bulk Temperature In response to items one and two.there are existing controls for monitoring and maintaining the drywell bulk temperature at or below 150*F. The drywell bulk temperature is detemined by an algorithm as described in the OCNGS Procedures. This algorithm applies weighting factors to the drywell themocouple readings to account for their location in the geometry of the containment volume. The attached summary of Calculation No.
C-1302-838-5360-003 includes this algorithm and its design basis.
During nomal plant operation, the control room operator monitors and receives a warning of an increasing drywell cooling fan supply air temperature via a l
recorder and alam. With an indication of increasing outlet fan temperature, OCNGS Procedure 2000-0PS-3024.09, Drywell Cooling System - Diagnostic Restoration Actions first requires a calculation of the drywell bulk temperature, and then provides for remedial action by the verification of key components or systems such as the Reactor Building Closed Cooling Water System, and drywell fans and coolers.
If these actions prove ineffective and the bulk temperature exceeds 150*F, then the operator enters Emergency Operating Procedure EMG 2000-3200.02 which provides methods of controlling and reducing the drywell temperature.
The existing OCNGS procedures already recognize the importance of the drywell bulk temperature and do provide a measure of assurance on the manner in which the plant is being operated. The main difference between the GE BWR-Standard Technical Specifications (3/4.6.1.7) and the OCNGS procedures is the stipulation of a time period for remedial action when the desien basis is not met.
In order to clarify this point, GPUN is proposing, in lieu of a T.S.,
the inclusion, prior to restart, of an eight hour time limit in the procedures for the remedial action.
If the design basis cannot be met within eight hours, GPUN will place the reactor in the shutdown condition.
Environmental Qualification (EQ) of Equipment t
The results of the (EQ) investigation for a drywell bulk temperature of 150*F, in Volume I (Figure 1.1) was not significantly different from that previously l
considered for detemining the qualified life of the Volume I equipment. Our evaluation has determined that there is no need to immediately replace the l
qualified electrical equipment in this region.
Target Rock globe valves, Pyco Temperature Elements and their associated cables are located in Volume II of the drywell.
The Volume II temperature corresponding to the bulk temperature of 150*F is calculated to be 205*F for the Target Rock valves and their associated cables, and 198*F for the Pyco temperature elements and their associated cables. The analysis of these l
temperatures, which has been evaluated and appropriately documented, demonstrates that there is no need to immediately replace this equipment and their associated cables, i
l l
1 3163f
/ With the absence of any qualified electrical equipment in Volume III, there is no change in its status.
Although it has been determined that there is no need for immediate replacement of the qualified equipment located in the drywell for a 150 F bulk temperature, the replacement of equipment will still be required, and will be addressed in the Plant's maintenance program.
This letter has been written in response to your request for supplemental infonnation.
If you have any further questions, please contact Mr. Michael Laggart, Manager BWR Licensing, at (201) 299-2341.
Very truly yours, n>}
e B.7Eedie'r '
ce President and Director Oyster Creek RFW/pa cc: Dr. Thomas E. Murley, Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 NRC Resident Inspector Oyster Creek Nuclear Generating Station Forked River, NJ 08731 Mr. Jack N. Donohew, Jr.
U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Phillips Building, Mail Stop 314 Bethesda, MD 20014 i
I 3163f
. =
ATTACHMENT I DRYWELL BULK TEMPERATURE ALGORITHM
SUMMARY
1.0 OBJECTIVE 1.1 Determine drywell volume fractions for the four sets of thermocouples (T/C 100 A thru E, T/C 103 A thru E, T/C 104 A thru E, T/C 105 A thru C) used to calculate drywell bulk temperature.
The volume fractions will be used to calculate a weighted average for drywell bulk temperature based on the volume each T/C set is assigned.
2.0 ALGORITHM
- 2.1 The weighted average calculation for drywell bulk temperature is:
TB = (Avg. T/C 100 x VIA/Vt) + (Avg. T/C 103 x VIB/Vt) +
(Avg. T/C 104 x VII/Vt) + (Avg. T/C 105 x VIII/Vt)
Where:
TB = Drywell Bulk Temperature V
= Drywell Volume Fractions (i.e., VIA, VIB, VII, VIII)
Vt = Drywell Total Volume T/C = Thermocouple 2.2 Figure 1-1 defines the drywell volume boundaries and thermocouples locations.
3.0 ASSUMPTIONS 3.1 The temperature stratification in the drywell was divided into four volumes based on available thermocouples locations.
3.2 Drywell vents and CR0 room volumes were included in the total drywell volume (V )+
t If the operator cannot immediately determine the drywell bulk temperature, the operator can monitor the drywell temperature by averaging the inlet temperatures of the operatino drywell recirculation fans.
If fewer than three fans are running, the operator averages the temperatures of the GEMAC narrow and wide range level reference legs (Panel 8R recorder).
3163f
'J
}
e FIGURE l-1 DRYWELL BULK TEMPERATURE ALGORITHM VOLUME B0UNDARIES AND THERM 0 COUPLE LOCATIONS
,/
b *-
es.sn'
=
,sw
'W M pe=t-I 0
/
M. hT D,e y
t I
/
e
,/
Vxs g
hI D T/c, tos A A6 l
\\
\\
\\
I,tLM' 431 8 y hI, T/C,IC6 A b w 6 g
TA f
/
l l
t t
.,l
/
l N
l N-
., - _ _ - - _. -.. - - _ _ _ -. - _.. _ _ _ ~ -. -. _, _ _ _ _ _, _. _ _ _. _ _ - _. _ _
.., _,,,. -.. _..A00000165 _44_.
_,