L-2006-146, License Amendment Request No. 186 Intake Cooling Water Pump Allowed Outage Time Change Response to NRC Request for Additional Information
| ML063480087 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 12/12/2006 |
| From: | Jones T Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2006-146, L-2006-268 | |
| Download: ML063480087 (12) | |
Text
Florida Power & Light Company, 700 Universe Boulevard, P.O. Box 14000, Juno Beach, FL 33408-0420 10 CFR 50.90 F*PL L-2006-268 December 12, 2006 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington D. C. 20555-0001 Re:
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 License Amendment Request No. 186 Intake Cooling Water Pump Allowed Outage Time Change Response to NRC Request for Additional Information By letter L-2006-146 dated June 21, 2006, Florida Power and Light Company (FPL) submitted a license amendment request to revise the Turkey Point Unit 3 and 4 Technical Specifications (TS). The change would revise the allowed outage time for one intake cooling water pump from 7 to 14 days.
Additional information was requested by the NRC staff in discussions with FPL representatives on December 11, 2006. The attachment to this letter contains the FPL reply to the questions from the NRC staff. The original No Significant Hazards Consideration Determination remains valid with the information provided herein and no revision of the requested TS change is involved.
In accordance with 10 CFR 50.91(b)(1), a copy of this letter is being forwarded to the State Designee for the State of Florida.
Should there be any questions concerning the information contained herein, please contact James Connolly at (305) 246-6632.
I declare under penalty of perjury that the foregoing is true and correct.
Very truly yours, Executed on Terry p*.ens Vice President Turkey Point Nuclear Plant
Attachment:
Response to NRC RAI cc:
Regional Administrator, Region II, USNRC USNRC Turkey Point Project Manager Senior Resident Inspector, USNRC, Turkey Point W. A. Passetti, Florida Department of Health
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an FPL Group company
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 1 of 11 Attachment Florida Power and Light Company Response to NRC Request for Additional Information Regarding License Amendment Request No. 186 Intake Cooling Water Pump Allowed Outage Time Change NRC Question:
- 1.
Regulatory Guide 1.174 Tier 2 evaluation is intended to establish an early evaluation to identify and preclude potentially high risk plant configurations. The Configuration Risk Management Program (CRMP) can be used to determine such configurations. Tier 3 evaluation is the establishment of a CRMP at the time of the plant equipment outage.
The need for this third tier stems from the difficulty of identifying all possible risk-significant configurations under Tier 2 that will be encountered over extended periods of plant operations. Please identify for the 14-day outage time any high risk plant configurations that may occur and the compensatory measures/commitments to ensure these configurations do not occur during the extended completion time.
FPL Response:
Based on a review of the cutsets for corrective maintenance and preventative maintenance cases, the risk significant configurations involved common cause failures of intake cooling water (ICW) pumps and reactor coolant pump seal loss of coolant accident (LOCA) related scenarios.
Compensatory measures are not needed. The existing programs (Technical Specifications) and other notes in the On-Line Risk Monitor are considered sufficient because the scenarios have relatively low risk contribution. Due to low risk associated with one ICW pump being out-of-service for 14 days, no Tier 2 high-risk plant configurations are identified.
NRC Question:
- 2.
In Section 5.4.3 of the license amendment request, Tier 3 credits the capability at Turkey Point to perform a configuration-dependent assessment of the overall impact on risk of proposed plant configurations prior to, and during, the performance of maintenance activities that remove equipment from service. Risk is re-assessed if an equipment failure, malfunction or emergent condition produces a plant configuration that has not previously been assessed. Does this model credit recovery of the out-of-service equipment? If "yes" describe how the program will correctly assess and manage risk during online performance of the manufacturer's recommended maintenance, since the
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 2 of 11 intake cooling water pump (ICWP) will not be recoverable until the maintenance evolution is concluded.
FPL Response:
The On-Line Risk Monitor tool used does not credit the equipment out-of-service, i.e., it assumes that the probability of equipment that is out-of-service is 1.0. The risk assessment and management program (i.e., Maintenance Rule a(4)) requires the plant to assess the risk of the configuration and based on the calculated core damage frequency (CDF), incremental conditional core damage probability (ICCDP), large early release fraction (LERF), and incremental conditional large early release probability (ICLERP), manage the risk according to plant procedure 0-ADM-225, On Line Risk Assessment and Management.
NRC Question:
- 3.
How was common cause failure treated when calculating risk for corrective maintenance?
For preventative maintenance?
FPL Response:
In the case of corrective maintenance, common cause events for failure of all ICW pumps (due to the same cause) were set equal to their related beta factor probability.
In the case of preventative maintenance, common cause events for failure of all ICW pumps (produced in the cutsets that were obtained by the corrective maintenance case) were set with probability equal to nominal values (i.e., baseline values).
NRC Question:
- 4.
Please provide a detailed breakdown of the historical and estimated ICWP unavailability on all 3 ICWP's for preventative and corrective maintenance. Please include if the event on May 20, 2006, affected ICWP unavailability.
FPL Response:
Since this license amendment request (LAR) was originally submitted based on a model placed in service in January 2005, any events in 2006 were not included in the PSA model used.
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 3 of 11 For unavailability data, see the following mitigating systems performance indicator (MSPI) basis document tables covering 2002 through 2004 plus additional data through the 3rd quarter of 2006 from the Institute of Nuclear Power Operations (INPO) consolidated data entry (CDE) and the cognizant system engineer for all 6 ICW pumps. Note that the 59.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> shown for the 3B ICW pump unplanned unavailability in the 2 nd quarter of 2006 is for the May 20, 2006 flange replacement referred to in the question.
A bounding calculation was performed using twice the unavailability assumed in the original LAR. Results indicate a CDF increase of 11% which is in Region III (least risk-significant) of Figures 3 and 4 of Regulatory Guide 1.174. This is a slight increase from the results of the bounding analysis provided in the original LAR which showed a CDF increase of 9%. The LERF increase was negligible in both bounding analyses.
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 4 of 11 flo1r 1 T T~na,,aahl1-,
nhfn fcnr TOWJ. Pimn I A 1Q02 2Q02 3Q02 4Q02 1Q03 2Q03 3Q03 4Q03 1Q04 2Q04 3Q04 4Q04 (hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
-(hours)
(hours)
(hours)
Unplanned UA 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Planned UA 0.00 5.33 16.50 13.50 0.00 13.83 0.00 55.25 15.45 19.32 1.13 0.00 Critical Hours 2160.00 2183.00 2208.00 2209.00 1472.90 2095.20 2208.00 2209.00 2184.00 2183.00 1 2102.10 610.30 Total Planned Hrs 140.31 (2002 - 2004)
Total Unplanned Hrs 0.00 (2002 - 2004)
Total Critical Hours 23824.50 Baseline UA (2002 - 2004)
Generic Baseline Unplanned Planned Unplanned UA Baseline Planned&
[
5.89E-N 5..89E-03 U00.OOE+00 Unplanned UA
" -- ::,:,;. i 030.
3A ICWP 1Q05 2Q05 3Q05 Planned 46.93 43.32 130 Unplanned 0
0 0
4Q05 6
0 1Q06 0
0 2QO6 0.2 0
3QO6 13.5 0
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 5 of 11 Baseline Unavailability Data for ICW Pump 3B 1Q02 2Q02 3Q02 4Q02 1Q03 2Q03 3Q03 4Q03 1Q04 2Q04 3Q04 4Q04 (hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours) -(hours)
(hours)
Unplanned UA 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Planned UA Hours 17.00 2.17 0.00 4.58 0.00 17.75 33.78 0.00 21.67 0.00 0.00 0.00 Critical Hours 2160.00 2183.00 2208.00 2209.00 1472.90 2095.20 2208.00 2209.00 2184.00 2183.00 2102.10 610.30 Total Planned Hrs 96.95 (2002 - 2004)
Total Unplanned Hrs 0.00 (2002 - 2004)
Total Critical Hours 23824.50 Baseline UA (2002 - 2004)
Generic Baseline Unplanned Planned Unplanned UA Baseline Planned &
j7:
4.07E-NA Unplanned UA J
j________ 03 0:OOE+:0 3B ICWP Planned Unplanned 1Q05 2Q05 0
20.38 0
0 3QO5 0
0 4QO5 0
0 1Q06 0
0 2Q06 89.1 59.5 3QO6 16.3 0
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 6 of 11 Baseline Unavailability Data for ICW Pump 3C 1Q02 2Q02 3Q02 4Q02 1Q03 2Q03 3Q03 4Q03 1Q04 2Q04 3Q04 4Q04 (hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
Unplanned UA 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Planned UA Hours 15.95 17.33 12.92 29.02 53.25 62.86 0.00 0.00 0.28 24.67 0.30 0.00 Critical Hours 2160.00 2183.00 2208.00 2209.00 1472.90 2095.20 2208.00 2209.00 2184.00 2183.00 2102.10 610.30 Total Planned Hrs 216.58 (2002 - 2004)
Total Unplanned Hrs 0.00 (2002 - 2004)
Total Critical Hours 23824.50 Baseline UA (2002 - 2004)
Generic Baseline Unplanned Planned Unplanned UA UaelnePlanned UA 9.09E-~
03
.OOE+00 N
Baseline Planned &
9.09E-NA30 3C ICWP 1Q05 2Q05 3Q05 4Q05 1Q06 2Q06 3Q06 Planned 3.5 52.35 0
0 14.35 0.1 41.4 Unplanned 0
0 0
0 0
0 0
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 7 of 11 Baseline Unavailability Data for ICW Pump 4A 1Q02 2Q02 3Q02 4Q02 1Q03 2Q03 3Q03 4Q03 1Q04 2Q04 3Q04 4Q04 (hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
Unplanned UA 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Planned UA Hours 0.00 24.91 0.00 76.75 0.00 0.00 3.42 4.37 0.00 36.12 0.00 12.35 Critical Hours 1944.00 2026.20 2208.00 2209.00 2160.00 2183.00 2208.00 1506.10 2184.00 2141.90 2208.00 2187.50 Total Planned Hrs 157.92 (2002 - 2004)
Total Unplanned Hrs 0.00 (2002 - 2004)
Total Critical Hours 25165.70 Baseline UA (2002 - 2004)
Plann~edUnplanned Generic Baseline Unplanned UA Baseline Planned &
6.28E-.NA Unlane U 0.OOE+00 NA Unplanned UA 03.
4A ICWP 1Q05 2Q05 3Q05 4Q05 Planned 29.54 0 0
0 Unplanned 0
0 0
0 1Q06 2Q06 3Q06 1.5 67.1 0
0 0
0
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 8 of 11 Baseline Unavailability Data for ICW Pump 4B 1Q02 2Q02 3Q02 4Q02 1Q03 2Q03 3Q03 4Q03 1Q04 2Q04 3Q04 4Q04 (hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
Unplanned UA 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Planned UA Hours 0.00 2.17 14.25 7.62 5.83 0.42 20.67 0.00 86.50 0.00 0.00 0.00 Critical Hours 1944.00 2026.20 2208.00 2209.00 2160.00 2183.00 2208.00 1506.10 2184.00 2141.90 2208.00 2187.50 Total Planned Hrs 137.46 (2002 - 2004)
Total Unplanned Hrs 0.00 (2002 - 2004)
Total Critical Hours 25165.70 Baseline UA (2002 - 2004) 25165.70_BaselineUA Planned Unplanned Generic Baseline Unplanned UA Baseline Planned &
4 5.46E-N 5.46EU03nlneUA103 0.OOE+00 NA Unplanned UA I
111,
03::
4B ICWP 1Q05 2Q05 Planned 21 15.97 Unplanned 0
0 3Q05 0
0 4Q05 19.17 0
1Q06 2
0 2QO6 2.1 0
3Q06 0
0
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 9 of 11 Baseline Unavailability Data for ICW Pump 4C 1Q02 2Q02 3Q02 4Q02 1Q03 2Q03 3Q03 4Q03 1Q04 2Q04 3Q04 4Q04 (hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
(hours)
Unplanned UA 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Planned UA Hours 0.00 3.25 116.52 0.28 0.00 4.42 0.00 0.00 18.98 60.12 0.00 0.00 Critical Hours 1944.00 2026.20 2208.00 2209.00 2160.00 2183.00 2208.00 1506.10 2184.00 2141.90 2208.00 2187.50 Total Planned Hrs 203.57 (2002 - 2004)
Total Unplanned Hrs 0.00 (2002 - 2004)
Total Critical Hours 25165.70 Baseline UA (2002 - 2004)
Generic Baseline Unplanned Planned Unplanned UA Baseline Planned &
8.09E-NA Unplanned UA 03 0.OOE+0.
4C ICWP Planned Unplanned 1Q05 2Q05 3Q05 4Q05 1Q06 2Q06 3Q06 0
0 0
0 0
0 0
0 0
0 0
0 0
0
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 10 of I1 NRC Question:
- 5.
What is the entire scope of the probabilistic safety assessment model? Please include what modes are modeled.
FPL Response:
The Turkey Point PSA model is limited scope level 2, at-power, and internal events only.
Shutdown and external events are not included in the PSA model.
NRC Question:
- 6.
Please provide changes to the model during the most recent model update since the individual plant examination of external events (IPEEE).
FPL Response:
The major changes in the most recent model update include the modeling of nitrogen backup for the atmospheric dump valves (ADV), modeling of the recovery event of switching the auxiliary feedwater (AFW) Train 1 steam supply to the "B" steam generator given a steam generator tube rupture (SGTR) in the "C" steam generator, and the addition to the model of a vessel rupture initiating event.
NRC Question:
- 7.
Please provide an explanation of the difference in core damage frequency and large early release frequency for corrective maintenance and preventative maintenance.
FPL Response:
The differences in the CDFs and LERFs for the corrective versus preventive maintenance cases are due to the treatment of the common cause failure probabilities. For the corrective maintenance case, an ICW pump failure is assumed, therefore, the probability of the other two pumps failing for the same reason (common cause) was set to the relevant beta factor. This beta factor is substantially greater than the common cause failure probability itself, which consists of the product of the beta factor and the independent failure probability. For the preventive maintenance case, there is an ICW pump out-of-service for elective maintenance, i.e., there has
FPL Letter L-2006-268 Response to NRC Request for Additional Information License Amendment Request No. 186 Attachment Page 11 of 11 not been an ICW pump failure. Therefore, the common cause failure probabilities were left at their nominal values.
NRC Question:
- 8.
Clarify the statement found in section 5.2 of the license amendment request that states "A longer [allowed outage time] allows more maintenance to be accomplished during a given on-line maintenance period and would therefore improve maintenance efficiency. Thus, total ICWP unavailability may be reduced with proposed change." Why does core damage frequency increase?
FPL Response:
More efficient and effective maintenance will improve component reliability and thus reduce total ICWP unavailability. However, the PSA model is based on past performance data and does not reflect the reduction of unavailability.
- 9. In section 5.4.1.3, the statement, "the revised fire estimates for the cable spreading room are at least two orders of magnitude lower than that reported in the original Turkey Point IPEEE" is in conflict with the next sentence which states, "Although the IPEEE fire risk model has not been updated..." Please clarify this discrepancy.
FPL Response:
The IPEEE fire risk model consists of many fire zones (including the cable spreading room and over one hundred other fire zones). In addition, it is based on a screening approach; the "best-estimate) core damage frequency is not easily calculated. The cable spreading room and control room were analyzed in more detail for specific applications.