ML071380410
| ML071380410 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 05/17/2007 |
| From: | Adrian Muniz Plant Licensing Branch III-2 |
| To: | DTE Energy |
| muniz A, ADRO/DORL/415-4044 | |
| References | |
| TAC MD2618 | |
| Download: ML071380410 (4) | |
Text
From:
Adrian Muniz To:
gastonr@dteenergy.com Date: 05/17/2007 1:49:33 PM
Subject:
Fermi 2 - Extension of the Completion Time for an Inoperable Emergency Diesel Generator(TAC. MD2618)
Mr. Gaston:
By letter dated July 12, 2006, Detroit Edison Company submitted a license amendment request to modify Conditions, Required Actions and Completion Times associated with the inoperability of one or more emergency diesel generators in Technical Specification 3.8.1 for Fermi 2. On November 27, 2006, the NRC staff sent, informally via electronic mail, questions regarding the proposed change.
L. Raghavan, NRR Branch Chief, in a phone conversation on May 16, 2007, expressed his concerns to you regarding the lack of a response to the information requested. He requested and you agreed, to provide a response by May 23, 2007.
For your convenience, I am including the questions as an attachment to this electronic mail.
Sincerely, Adrian Muniz Fermi 2 Project Manager CC:
Lakshminaras Raghavan Mail Envelope Properties (464C95AD.C03 : 4 : 10066)
Subject:
Fermi 2 - Extension of the Completion Time for an Inoperable Emergency Diesel Generator(TAC. MD2618)
Creation Date 05/17/2007 1:49:33 PM From:
Adrian Muniz Created By:
AXM8@nrc.gov Recipients Action Date & Time dteenergy.com Transferred 05/17/2007 1:50:08 PM gastonr (gastonr@dteenergy.com) nrc.gov TWGWPO03.HQGWDO01 Delivered 05/17/2007 1:49:40 PM LXR1 CC (Lakshminaras Raghavan)
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Delivered & Opened DRAFT REQUEST FOR ADDITIONAL INFORMATION AMENDMENT REQUEST TO EXTEND COMPLETION TIME FOR DIESEL GENERATORS FROM 7 DAYS TO 14 DAYS FERMI 2 By letter dated July 12, 2006, Detroit Edison proposed changes to Fermi 2 Technical Specifications for extending the completion time (CT) for an emergency diesel generator (EDG) from the current 7 days to 14 days. In order for the Nuclear Regulatory Commission (NRC) staff to proceed with its review of the proposed change, the following information is needed:
1.
The NRC staff has required in the past that the power source that will be available as a backup to the inoperable EDG must have capacity equal to or greater than the capacity of the inoperable EDG. In addition, the technical specification (TS) should contain requirements to demonstrate by testing, before taking one EDG out of operation for an extended period, that the power source is available and functional and the TS should contain requirements to take action when the power source becomes unavailable during the extended EDG outage duration. Please discuss how the above NRC staff requirements would be satisfied.
2.
Since the Combustion Turbine Generator (CTG) 11-1 is being used as a backup to an inoperable EDG during the extended EDG outage, please provide the following information:
A.
What is the capacity of the CTG 11-1?
B.
Specify the time it will take to manually connect the CTG 11-1 to the safety bus.
C.
Does CTG 11-1 meet the requirements of NUMARC 87-00, Appendix B and RG 1.155?
D.
Are CTG 11-1 system components in a maintenance and monitoring program?
E.
Please specify loads it will be powering and their power requirements.
3.
Please discuss what type of communication protocol has been established between the control room operator at Fermi and the transmission system operator? Is the transmission system operator notified in advance that the EDG is going to be taken out for an extended period of time?
4.
Discuss and provide information on the reliability and availability of offsite power sources relating to the proposed change. The discussion should include duration, cause, date and time of each loss-of-offsite power (partial or complete) event.
5.
Provide the reliability and unavailability of all EDGs in the last few years. Also, discuss the impact of CT extension on EDG unavailability per Maintenance Rule.
6.
It is staffs understanding that the purpose of the requested amendment is to allow an increased outage time during plant power operation for performing EDG inspection, maintenance, and overhaul, which would include disassembly of the EDG. EDG operability verification after a major maintenance or overhaul may require a full load rejection test. If a full load rejection test is performed at power, please address the following:
a.
What would be the typical and worse-case voltage transients on the 4160-V safety buses as a result of a full-load rejection?
b.
If a full-load rejection test is used to test the EDG governor after maintenance, what assurance would there be that an unsafe transient condition on the safety bus (i.e., load swing or voltage transient) due to improperly performed maintenance or repair of a governor would not occur?
c.
Using maintenance and testing experience on the EDG, identify possible transient conditions caused by improperly performed maintenance on the EDG governor and voltage regulator. Discuss the electrical system response to these transients.
d.
Provide the tests to be performed after the overhaul to declare the EDG operable and provide justification of performing those tests at power.
7.
The staff noticed that Required Actions A.3 and A.5 related to CTG 11-1 are being proposed to be deleted. Provide justification for deleting these Required Actions, specifically when CTG 11-1 is being used as a backup to the inoperable EDG during the EDG CT extension.
8.
The staff believes that certain compensatory measures are needed during the extended EDG CT to assure safe operation of the plant. In the past, other licensees have provided the following regulatory commitments in their EDG CT extension requests.
Provide a discussion as to how you would address each commitment listed below as it relates to Fermi 2.
The extended CT will be typically used to perform infrequent (i.e., no more frequently than once every 24 months) diesel manufacturers recommended inspections and preventive maintenance activities; No maintenance or testing that affects the reliability of the train associated with the OPERABLE EDG will be scheduled during the extended CT. If any testing and maintenance activities must be performed while the extended CT is in effect, a 10 CFR 50.65(a)(4) evaluation will be performed.
A alternate power source with capacity equal to or greater than the capacity of the inoperable EDG will be available as a backup to the inoperable EDG. After entering the extended CT, this source will be verified available every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and treated as protected equipment.
The scheduling of EDG preplanned maintenance will be avoided during seasons when the probability of severe weather or grid stress conditions are high or forecasted to be high.
The system load dispatcher will be contacted once per day to ensure no significant grid perturbations are expected during the extended allowed outage time. Also, the system load dispatcher should inform the plant operator if conditions change during the extended CT (e.g., unacceptable voltages could result due to a trip of the nuclear unit).
Component testing or maintenance of safety systems and important non-safety equipment including offsite power systems (auxiliary and startup transformers) that increase the likelihood of a plant transient or LOOP will be avoided. In addition, no discretionary switchyard maintenance will be allowed.
TS requirements of verification that the required systems, subsystems, trains, components, and devices that depend on the remaining EDG(s) are operable and positive measures will be provided to preclude subsequent testing or maintenance activities on these systems, subsystems, trains, components, and devices.
Steam-driven feedwater pump will be controlled as protected equipment, and will not be taken out of service for planned maintenance while an EDG is out of service for extended maintenance.
Any component testing or maintenance that increases the likelihood of a plant transient would be avoided; plant operation should be stable during the EDG CT.
(This condition could include consideration of degraded or out-of-service balance-of-plant equipment.)