ML20065R991
| ML20065R991 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/20/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20065R982 | List: |
| References | |
| NUDOCS 8210290385 | |
| Download: ML20065R991 (3) | |
Text
.
w:
1%,
UNITED STATES NUCLEAR REGULATORY COMMISSION
{
g c
-l wasmucioN, D. C.20655
- ...../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 48 TO FACILITY OPERATING LICENSE NO. NPF-3 TOLEDO EDISON COMPANY A'ND CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1 DOCKET NO. 50-346 1.0 Introduction 4
By letter dated May 5,1932 (No. 003), The Toledo Edison Company requested amendment to Facility Operating License No. NPF-3 for the Davis-Besse Nuclear Power Station, Unit No.1.
The amendment would modi.fy the Tech-nical Specifications (TSs) to allow a change in the calculational method 4
for determining the maximum allowable high flux trip setpoint when one or more safety valves on any steam generator are inoperable. The amendment would revise Table 3.7-1 and Bases 3/4.7.1.1 of Appendix A to License No.
2.0 Discussion and Evaluation I
{
Overpressum pmtection for the steam generator secondary side is pro-t-
vided by 18 safety valves - 9 per steam generator. The specified valve lift settings and relieving capacities are in accordance with the require-
{
ments of Section III of the ASME Boiler and Pressure Vessel Code,1971 edition. This Code requires that valve lift settings and relief capacities r
be such that the steam system pressure will not exceed 110% of system design pressum of 1050 psig in the event of the most severe anticipated f_
operational transient.
I The most severe anticipated operational transient from the viewpoint of
{
detemining relief capacity is a turbine trip from maximum permissible power coincident with a loss of condenser heat sink.- Under these condi.
tions, the entire steam generation must be relieved through the safety '
valves.
The ASME Boiler and Pressure Vessel Code requires that the required relieving capacity be obtained by the use of at least two pressure-relief valves. Thus, it is pemissible to operate with one or more of the in-stalled safety valves inoperable as long as: 1) at least two safety valves per steam generator are operable and 2) the reactor high flux trip-point is reset to provide a corresponding reduction in the required relieving capacity.
5 8210290383 821020 DR ADOCK 05000346 PDR e
e
._____m.
e.
08-1 The total installed relieving capacity for the 18 safety valves is 14,174,922 lb/hr or about 7,087,500 lb/hr per steam generator at 1155 psi g.
This is equivalent to 120% of the steam flow at 100% rated themal power. The current TSs allow for operation with inoperable safety valves
)
but uses the total installed relieving capacity as the normalizing basis
~~
for detemining the required high flux trip setpoint. Thus, the TSs do not give full credit for the excess installed relieving capacity. Toledo Edison Company proposes to revise the method for detemining the high flux
(
trip setpoint. The proposed method would use the required relieving l
capaci ty, 6,585,000 lb/hr per steam generator, as the normalizing basis.
3 This change would allow credit for excess installed flow relieving capacity permitting operation at higher power than currently allowed in the event q
of one or more inoperable safety valves.
l Toledo Edison Company also proposes changes to Table 3.7-1 of the TSs con-sistent with the proposed revised method described above. This table specifies the Inemal power restriction as a function of the nunber of inoperable safety valves on any steam generator and ensures that a minimum of two safety valves per steam generator will be operable as required by the ASME Boiler and Pressure Vessel Code.
We have reviewed the licensee's proposed change to the equation for detemining the high flux trip setpoint as a function of the number of inoperable safety valves and the proposed changes to Table 3.7-1 of the TSs. We conclude that these changes are acceptable. The changes will l
pemit operation with a higher trip setpoint but will maintain adequate L
relieving capacity.
k 3.0 Environmental Consideration We have detemined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant envirorrnental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental impact statement, or negative declaration and environ-mental impact appraisal need not be prepared in connection with the issuance of this amendment.
4.0 Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated, does not create the possibility of an accident of a type different from any evaluated previously, and does not involve a significant reduction in a margin of safety, the amendment does not involve a significant hazards cor. sideration, (2) there is reasonable assurance i
mx...
x m.._.,m.,, _
y_
a.
08-1 that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Dated: October 20, 1982 The following NRC personne1 have contributed to this Safety Evaluation:
~
A. De Agazio.
I t
i h
I I
?
- r,
~
3 o
w
=w e - im et 7 h6 *ph '*
""~"it MgM.D A '