ML18045A893
| ML18045A893 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/08/1980 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Nielson L AFFILIATION NOT ASSIGNED |
| References | |
| NUDOCS 8007180463 | |
| Download: ML18045A893 (9) | |
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LOSS OF OFFSITE POWER SURVEY STATUS REPORT REVISION l
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Prepared by*:
Raymond F. Scholl, Jr.; P.E Systematic Evaluation Program Brar~h Division of Licensing
- Peer review group:
D. Tondi M. Chiramal
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LOSS OF OFFSITE POWER SUKVEY STATUS REPORT Abstract: This report describes the methods for data analysis and the results of a survey of loss of power events at dorrestic nuclear power plants.
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Introduction:==
As a result of the staff efforts on several related Generic Activities (e.g., A-35 and A-44) the staff became concerned about the accuracy of the available loss of offsite power data. This concern, along with the results of the Lewis Study, lead the staff to request that all nuclear power plants provide the information specifted in Table 1.
Of the 69 licensed nuclear power plants, 20 did not respond.
These plants are identified in Table 2.
Discussion:
The steps in data reduction and analysis are summarized below.
- 1.
The data was sorted into Tyoe A or B data in accordance with Table 1.*
- 2.
For each event a cause code was assigned.
The cause codes are presented in Table 3.
- 3. A map showing the distribution of the number of each type of failure as a function of each respondant plant was prepared.
This is presented as Table 4.
- 4.
The "age" of each plant was determined based on the date of its first reported loss of offsite power until March 3, 1980.
This date is presented as Table 5.
(Because Duane Arnold,
reported that no loss of offsite power events, the age could not be established and all data fields were set to zero.)
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TABLE 1 REQUEST FOR ADDITIONAL INFORMATION A.
For losses of offsite power where less than all offsite power was lost:
l.
- 2.
- 3.
- 4.
How many circuits to the offsite network are normally available and how many were lost during the event?
What was the cause of the event?
Why did the other lines not fail when some did fail?
Was any voltage increase or decrease experienced just prior to or during the outage? If so, please give details, voltages reached, decay rate, affects on equipment operation, etc.?
- 6.
How long was power unavailable from the circuit?
- 7.
Date of Event.
B.
For losses of all offsite power:
- l.
How long was the Power off?
How long for partial recovery?
Please give details.
- 2.
If turbine trip occurred, how soon after did loss of offsite power occur?
- 3.
If power was recovered promptly (10 minutes or less), was it due to automatic or manual actions?
- 4.
Was any voltage increase or decrease experienced just prior to or during the outage? If so, please give details, voltage~ reached, affects, etc.
- 5.
Was any frequency decay experienced just prior to or during the outage? If so, please give details, lowest frequency reached, decay rate, affects on equipment operation, etc~
- 6.
Date of Event.
C.
Were there any other loss of offsite power events other than we have listed? If so, please give details of each event.
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TABLE 2 PLANTS NOT PROVIDING THE DATA REQUESTED IN TABLE 1 ORB#l 50-305 Kewaunee 50-338 North Anna 1 50-261 H.B. Robinson 2 50-280 Surry 1 50-281 Surry 2 50-295 Zion 1 50-304 Zion 2 ORB#3 50-325 Brunswick 1 50-366 E.I. Hatch 2 ORB#4 50-368 Arkansas 2 50-309 Maine Yankee 50-313 Arkansas l 50-302 Crystal River 3 50-346 Davis-Besse 1 50-269 Oconee 1 50-270 Oconee 2 50-287 Oconee 3 50-312 Rancho Seco 50-289 Three Mile Island l 50-320 Three Mile Island 2
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- Code 1 ?
lo 11 i 2 3
4 5
7 9
10 11 12 13 14 15 20 22 23 24 25 28 29 31 32 33 34 35 36 42 Cause Not reported Unknown TABLE 3 Failure in an instrument inverter with a second channel bypassed.
Turbine generator voltage regulator failure Manual scram Circuit breaker trip during relay testing, improper yard switching operations, improperly set relays, maintenance errors, relay testing errors, test equipment failure, CT failure, maintenance outages Ground fault with or without protective relaying failure or with or without manual scram, bolted faults Protective relay failure Insulator failure (lightening arrester, transmission line irtsulator, transformer bushing, pot head, cable insulation)
Turbine runback due to loss of control rod position indication Lightening with redundant line(s) out of service for maintenance Inadequate line height Foreign conducting object Overload Winter stonn Breaker failure Lightening System undervoltage Transformer winding failure Forest fires Lightening with breaker failure Construction activities Surrmer storm System collapse False relay operation with redundant line(s) out of service for maintenance Mechanical failure of conductors or stays or supporting structures other than code 36 Automatic. scram Motor vehicle hitting pole System imba11ance
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TABLE 5 3 Indian Point 7.62 278 Peach Bottom 3 5.8 10 Dresden 1
- 13. 31 282 Prairie Island 1 2.91 29 Yankee Rowe 16.73 285 Ft. Calhoun 6.51 133 Humboldt Bay 9.29 286 Indian Point 3 2.63 155 Big Rock Point
- 8. 1 293 Pilgrim 1 8.04 206 San Onofre 1
- 12. 12 296 Browns Ferry 3 5.92 213 Haddam Neck
- 11. 85 298 Cooper 4.03 219 Oyster Creek
- 12.
301 Point Beach 2 9.07 220 Nine Mile Point 6.29 306 Prairie Island 2 2.91 237 Dresden 2 6.0 315 D.C. Cook 1 5.04 244 Ginna
- 9. 17 316 D.C. Cook 2 5.04 245 Mi 11 stone 1 8.69 317 Calvert Cliffs 1 6.2 247 Indian Point 2 7.62 318 Calvert Cliffs 2 4.09 249 Dresden 3
-6.0 321 E.I. Hatch l 2.43 250 Turkey Point 3
- 6. 01 324 Brunswick 2 4.94 251 Turkey Point 4
- 6. 01 331 Duane Arnold 254 Quad Cities 1 4.52 333 Fi tzPa trick 1.42 255 Palisades 8.66 334 Beaver Valley 1 2.89 259 Browns Ferry 1 5.92 335 St. Lucie l 2.8 260 Browns Ferry 2 5.92 336 Millstone 2 3.87 263 Monticello 8.96 344 Trojan 3.88 265 Quad Cities 2 4.52 348 Farley 1 2.46 266 Point Beach 1 9.07 409 Lacrosse 9.12 271 Vennont Yankee 7.84 272 Sa 1 em 1 2.84 277 Peach Bottom 2 5.8
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- 5.
The data of Table 4 was re-plotted as a function of age to yield failure rates (failures/year).*
- 6.
The data was subjected to several different analyses to determine if it coJ1d be characterized on a ~eneric basis.
These attempts were not generally successfull because of the large scatter in the data.
However, all attempts are identified in the results below.
- 7.
Beyond the attempts to characterize the data on a generic basis, each plant was evaluated, for each of the causes, to determine if its failure experience was significantly different from the average.
Significant was defined as a "target" valve (failures/
year) greater than or equal to the mean plus three standard deviations.
Results:
The following are the numerical results of this study.
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- 8.
- 9.
- 10.
- 11.
There have been 806 reported total and partial losses off offsite power.
This represents a mean failure rate of 2,29 failures/year with a standard deviation of 3.73 failures/year.
There have been 85 total losses of offsite power reported by the 49 respondants.
This represents an average rate of 0.24 failures/year.
The mean duration of a total loss of offsite power is 3.88 hours0.00102 days <br />0.0244 hours <br />1.455026e-4 weeks <br />3.3484e-5 months <br /> with a standard deviation of 5.89 hours0.00103 days <br />0.0247 hours <br />1.471561e-4 weeks <br />3.38645e-5 months <br />.
The mean time to partial recovery (from a total loss of offsite power) is 1.83 hours9.606481e-4 days <br />0.0231 hours <br />1.372354e-4 weeks <br />3.15815e-5 months <br /> with a standard deviation of 4.54 hours6.25e-4 days <br />0.015 hours <br />8.928571e-5 weeks <br />2.0547e-5 months <br />.
The duration of a partial loss of offsite power is 10.36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> with a standard deviation of 162.61 hours7.060185e-4 days <br />0.0169 hours <br />1.008598e-4 weeks <br />2.32105e-5 months <br />.
An attempt was made to obtain a least ~~uares fit of the mean valv: of the time of outage vs. the percentage of offsite power lost (%lines).
No such fit was achieved (confidence level was less than 95%).
The mean duration of outage due to liqhtning strikes is 0.62 hours7.175926e-4 days <br />0.0172 hours <br />1.025132e-4 weeks <br />2.3591e-5 months <br /> with a standard deviation of 4.19 hours2.199074e-4 days <br />0.00528 hours <br />3.141534e-5 weeks <br />7.2295e-6 months <br />.
The mean voltage drop is 8.98% with a standard de~iation of 15.21%.
The mean frequency drop is 3.42 Hz with a standard deviation of
- 5. 64 Hz.
The mean frequency _decay rate is L42 Hz/sec with a standard deviation of 1.84 Hz/sec.
The Dresden Units 2&3 reported the most significant annual failure rates as noted below:
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{a) Total failure rate 17.17 vs.a target of 13.47,
{b) Cause 0 failure rate 4 vs.a target of 2.97,
{c) Cause 7 failure rate 0.67 vs.a target of 0.63,
{d) Cause 9 failure rate 3 vs. a target of 2.38,
{e)
Cause 12 failure rate 0.17 vs. a target of 0.12,
{f) Cause 13 failure rate 0.5 vs. a target of 0.5, (g)
Cause 15 failure rate 2 v~ a target of 1.67, (h)
Cause 22 failure rate 3.83 vs. a target of 2.84, and (i) Cause 42 failure rate 0.17 v~ a target of 0.13.
- 12. Palisades has exhibited the second largest number of target violations. These are:
(a)
Cause 4 failure rate 3.59 v~ a target of 2.29, (b)
Cause 5 failure rate 0.93 vs. a target of 0.55, (c) Cauase 11 failure rate of 1.5 vs. a target of 0.67, (d)
Cause 14 fa i 1 ure rate of 0.23 vs. a target of 0.1, and (e)
Cause 29 failure rate of 0.93 vs. a target of 0.45.
- 13. Pilgrim l has exhibited the third largest number of target violations. These are:
(a) Cause 13 failure rate of 0.87 vs. a target of 0.5, (b)
Cause 20 fa i1 ure rate of 0.25 vs. a target of 0.22, (c) Cause 35 failure rate of 0.12 vs. a target of 0.09, and.
(d)
Cause 36 failure rate of 0.37 vs. a target of 0.20.
- 14. Turkey Point 3 had 3 target violations.
- 15. Turkey Point 4 had 2 target violations.
- 16. All other correspondents have had one or fewer target violations.
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J Conclusions
- 1.
The loss of offsite power rate is 2.29 failures/reactor year for a partial loss and 0.24 failures/reactor year for total loss.
- z.
The Dresden and Palisades stations should be further evaluated to determine the causes for the target violations and to determine if suitable modifications can be made to reduce these rates.
- 3.
Depending on the results of the Dresden 2 and Palisades further evaluation, consideration should be given to similar studies of the Pilgrim station.
Recommendations
- 1.
Pursue the evaluation of Dresden 2 and Palisades.
- 2.
Obtain the data from the plants listed in Table 2.
- Data tables and resulting computer generated analyses are available from the author upon request.
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