ML20064B400
| ML20064B400 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/04/1990 |
| From: | Shelton D CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1852, NUDOCS 9010160311 | |
| Download: ML20064B400 (2) | |
Text
__
^
g gg l'
DensW C. Shelsen 300 Medeon Amue t
Vee President.Nuciser
- Toisdo, OH 436524001 Demisese (419)249 2300 L
Docket Number 50-346 l
1,1 cense Number NPF-3
^
Serial Number 1852 o
' October 4. 1990 United States Nuclear Regulatory Commission
)
Document Control Deok l
Vashington, D. C. '20555 Subject Containment Hydrogen Purge System Use During Plant Operation l
l Gentlemen:
This letter provides an updated status regarding venting-of containment for-pressure control during power operation at the Davis-Besse' Nuclear Power Station (DBNPS), Unit 1 (previously addressed in Toledo Edison (TE) letter Serial Number 1525, dated August 1, 1988), The information contained herein was discussed with Mr. P. M. Byron, Nuclear Regulatory Commission (NRC) Senior l
Resident Inspector, DBNPS, and Mr. A. H. Hsia, NRC/ Office of Nuclear Reactor l
Regulation (NRR) Backup Project Manager, DBNPS, on August 29, 1990, and August 30, 1990, respectively.
i The DBNPS Technical Specification 3/4.6.1,4-(Containment Systems, Internal 1
Pressure) limits primary Containment internal pressure, as a function of-differential pressure with the Shield Building, to between +25 inches and -14 inches water gauge (V.G.) during Operational Modes 1~, 2, 3 and 4.
These; limits ensure the Containment vill not exceed its design pressure of 40 psig j
during Loss of Coolant Accident conditions or its design negative pressure differential with respect to the annulus atmosphere of 0.5 psi.
1 i
During power operation the week of August 27, 1990, the internal pressure q
differential between the containment and.the annulus atmospheres reached 17 inches V.G.
This increase was investigated and determined to be the result of j
both an increase in the temperature of Service Water supplied to the 1
Containment Air Coolers and an increase in outside ambient temperature. Both J
conditions slightly reduced the normal heat transfer rate from containment.-
The decrease in heat transfer caused Containment temperature to be elevated such that it affected Containment pressure. Additionally, the variation in the barometric pressure outside the containment may also have affected the differential pressure between Containment and the annulus.
While the Containment temperature and the containment-to-annulus pressure differential j
remained vell within the bounds of the Technical ~ Specifications, the pressure i
9010160311 901004 PDR ADOCK 05000346 P
PDC 4
l I
.)
-OperatinD Componres j'
0 Cleveioad Electnc lituminating Toledo Edson
.2
Dockat Nu:.ber 50-346 Lic:n:0 Number NPF-3 g
Serici Nu bar 1852 Page 2 l
increase was viewed as undesirable. Therefore, a vent path was proposed i
through the Containment Hydrogen Purge (CHP) System piping to a temporary filtrntion unit (as described in letter Serial Number 1525) to reduce the i
Serial Number 1525, Toledo Edison stated that the CHP system would be used to pressure differential between the Containment and the annulus.
In letter reduce the differential pressure between the Containment and the annulus during plant heatup and power ascension. The current proposal was reviewed in light of the information contained in letter Serial Number 1525 and NRC Branch l
Technical Position (BTP) CSB 6-4.
It was determined that the justification provided in Attachment I to letter Serial Number 1525 was applicable for power i
operation as well as plant heatup and power ascension. That is, the radiological dose calculations performed for the evaluation in letter Serial Number 1525 vere performed utilizing source terms applicable to full power o
conditions, and, therefore, justified the use of the CHP System in-l' e n
configuration described therein during power operation.
Based on the above, Toledo Edison believes that the use of the CHP System during power operation (as well as during plant heatup and power ascension during Modes 1 through 4 as described in letter Serial Number 1525) is justified.
It is Toledo Edison's intent to utilize the CHP System during Mode i
1 power operation for those periods of increasing Containment pressure differential with the annulus when such increases can be attributed solely to increased service water and/or outside ambient air-temperature and their I
effeet on Containment temperature, changes in barometric pressure, or in accordance with the conditions stated in letter Serial Number 1525.
t Should you have any questions or require further information, please contact Mr. R. V. Schrauder, Manager - Nuclear Licensing, at (419) 249-2366.
l Very truly yours, hw Q RMC/mmb cci P. M. Byron, DB-1 NRC Senior Resident Inspector A. B. Davis, Regional Administrator, NRC Region III r
A. H. Hsia, NRC/NRR DB-1 Backup Project Manager H. D. Lynch, NRC/NRR DB-1 Senior Project Manager I
Utility Radiological Safety Board h
~ -,. ~,
--.-..,,.,,