ML20133L258
| ML20133L258 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 01/16/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20133L240 | List: |
| References | |
| NUDOCS 9701210542 | |
| Download: ML20133L258 (4) | |
Text
..
l G FIEQu U
4 UNITED STATES t
g g
NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 2066Mooi o
Y+9
,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 91 TO FACILITY OPERATING LICENSE NO. NPF-47 ff(IERGY OPERATIONS. INC.
RIVER BEND STATION. UNIT 1 DOCKET NO. 50-458
1.0 INTRODUCTION
By application dated May 30, 1996, the licensee (Entergy Operations, Inc.) for River Bend Station (RBS), Unit 1, requested an amendment to Facility Operating License NFP-47. The amendment proposed changes to Technical Specification (TS) Surveillance Requirement Section 3.8.3.4 regarding the pressure to be maintained in the start air receivers for the Division III emergency diesel generator. The staff has provided guidance for licensee's design and operation of starting systems for emergency diesel generators; see the Standard Review Plan 9.5.6 " Emergency Diesel Engine Starting System." One acceptable criterion is that receivers are to be sized and maintained at pressures which should be capable of cranking a diesel generator five times.
2.0 BACKGR0VND There are two standby diesel generators (DGs) designated as Division I DG (DG-1A) and Division II DG (DG-18); and one high pressure core spray power supply DG designated as Division III DG (DG-lC) at the River Bend Station, Unit 1 (RBS). The Division I and II DGs are started by admitting air to the cylinders of each diesel and if the diesel does not start, sufficient starting air remains for subsequent (or a total of five (5)) automatic or manual starts. The Division III diesel generator, however, has an air driven starter motor system and in an emergency, starting air is admitted to the starter motors untti the diesel starts or the air receiver tank is depleted of air.
With this starter motor arrangement, the requirement for sufficient starting air for five starts must be established on an equivalence basis, i.e., there should be sufficient air to attempt to start the diesel five times assuming the air supply was not continaous and each attempt provided sufficient air to start the diesel.
Currently, the TS requires 160 psig or higher of pressure to be maintained in each of the start air receivers for the three DGs. During an inspection conducted in the Spring of 1995, the staff identified that while this value is representative of a 5-start pressure for the Division I and II DGs, the capacity of Division III DG start air receiver at this pressure to provide 5 starts has not been established.
9701210542 970116 PDR ADOCK 05000458 P
1 By letter dated May 30, 1996, the licensee (Entergy Operations, Inc.) of RBS requested an amendment to Facility Operating License NFP-47. The amendment proposed changes to TS Surveillance Requirement Section 3.8.3.4 regarding the pressure to be maintained in the start air receiver for the Division III DG.
The proposed changes require the start air receiver for the Division III DG to be maintained at a pressure of equal to or higher than 200 psig. With the proposed change to the TSs, the licensee also clarified the starting air requirements for the Division I and 11 diesel generators at 160 psig.
3.0 EVALUATION Current TS Surveillance Reauirement Current TS Surveillance Requirement Section 3.8.3.4 requires that:
" Verify each required DG air start receiver pressure is 1160 psig."
Pronosed TS Surveillance Reauirement The licensee proposed to revise the above current TS Surveillance Requirement Section 3.8.3.4 in the following manner:
" Verify each required DG air start receiver pressure is:
a.
2 160 psig for DGs IA and IB; and b.
2 200 psig for DG 10."
In addition, the licensee revised the basis to reflect the above proposed TS Surveillance Requirement.
Current B uis Current basis associated with TS Surveillance Requirement Section 3.8.3.4, in part, states that:
For DG 1A and IB either the forward or the rear air start subsystem is capable of starting the respective DG when air receiver pressure is within limits. For DG IC both forward or rear air start subsystem must be within limits to start the DG.
Proposed Basis The licensee proposed to replace the above partial current basis associated with TS Surveillance Requirement Section 3.8.3.4 in the following manner:
For DG 1A and IB, each starting air system is sized to have the capacity for at least one emergency DG start attempt above the air pressure interlock, and multiple manual start attempts below the interlock, without recharging its start receiver (s).
i,
starting system is sized to have the capacity for at least five successive start attempts without recharging its air receiver.
For each DG, either the forward or rear air start subsystem has the capacity to satisfy these multiple start requirements.
With regard to Divisions I and II DG, each DG is provided with an air start 4
system which consists of two subsystems.
Each subsystem consists of one air compressor, one aftercooler, one air dryer, two air receivers, and associated i
piping, valves and controls. Each compressor is set to recharge its associated air receivers when the pressure drops to 235 psig and shuts off e
j-pressure of 160 psig to be maintained in each of the air receivers. Upon when the pressure reaches 250 psig. However, the RBS TS imposes a minimum receiving an emergency start signal, should the DG fail to start immediately, the DG continues to receive an automatic start attempt at cranking until the pressure in the air receivers falls to 120 psig. At this pressure, the air starting solenoid valves close to conserve starting air such that manual starts of the DG may be attempted. Normally with the air receiver pressure maintained above 235 psig, each air start system will have sufficient air inventory to start the associated DG eight times.
During the inspection conducted in the Spring of 1995, the inspection team reviewed the preoperational test results and concluded that both Division I and Division II DGs had demonstrated the capability of starting five times beginning with the start air receiver pressure at 160 psig and met the guidance descri!.ed in the Standard Review Plan (SRP) for DG start air system (see the NRC Inspection Report 50-458/95-10 dated July 6, 1995). Therefore, the inspection team found the Divisions I and II DG air receiver pressure maintained at 160 psig acceptable.
With regard to Division III DG, the air start system consists of two independent subsystems.
Each subsystem consists of one air compressor, one air dryer, one air receiver, two starting air motors, and associated piping, valves and controls.
Each compressor is set to recharge its associated air receiver when the pressure drops to 225 psig and shuts off when the pressure reaches 240 psig. The DG can be started with one bank of dual air starting motors. However, upon receiving a starting signal, both banks of dual air starting motors will crank the DG to ensure positive cranking.
The licensee performed DG-lC start air system tests which demonstrated that with the start air receivers initially pressurized to 200 psig, the air start system with the starting motors will be able to provide five DG start attempts. Since the compressors keep the receivers charged to between 225 and 240 psig, the licensee proposed to maintain the DG-lC start air receiver at a pressure equal to or higher than 200 psig as the Surveillance Requirement for Division III DG start air receiver.
Based on its review, the staff finds the above proposed changes to TS Surveillance Requirement Section 3.8.3.4 and the associated basis regarding the pressure to be maintained in the start air receiver for the Division III DG are consistent with the guidance described in the SRP and in NUREG-1434,
s 1 " Standard Technical Specifications, General Electric Plants, BWR/6."
Therefore, the staff finds them acceptable.
I
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Louisiana State Official was notified of the proposed issuance of the amendment. The State official J
had no comments.
l
5.0 ENVIRONMENTAL CONSIDERATION
i The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR l
Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types,
)
of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (61 FR 34892). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or i
environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
f 2
I The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, I
and (3) the issuance of the amendment will not be inimical to the common l
defense and security or to the health and safety of the public.
Principal Contributor:
D. Shum Date:
January 16, 1997 i
i
)
1 1