ML17192A829

Loss of Offsite Power - Survey Status Rept

ML17192A829
Person / Time
Site:	Dresden
Issue date:	07/08/1980
From:	Scholl R Office of Nuclear Reactor Regulation
To:
Shared Package
ML17192A828	List: ML17192A827 ML17192A829
References
NUDOCS 8007250035
Download: ML17192A829 (10)

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• LOSS OF OFFSITE POWER.

-SURV-E'.'t-S:rA:rUS-RERORT--~_:----. _* ___.. ____

REVISION 1

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Prepared by*:

Raymond F. Scholl, Jr.; P.E Sys tema tic Eva 1 uati on Program Brar-:h Division of Licensing

• Peer review group:.o. Tandi M. Chiramal 8007250035

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. LOSS OF OFFSITE. POWER SUl{VEY STATUS REPORT AbstraCt:

This' report describes the methods for data analysis and the results of a survey of loss of power events at domestic nuclear power plants. *

==

Introduction:==

• . As a result of the staff efforts on several relat~d Generic Act{v~ties (e.g., A-35 and A-44) the staff became concerned about the accuracy of the a~ailable 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 iriformation specified in lable 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

~low~

l.. 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 C3use codes are presented in Table 3.

3. A map showing the distribution of the number of each type of failure as a: function of e~ch respondant pla~t was prepared.

This is presented as Table 4.

4.. The "age" of each plant was determined based on the date of*

its first ~eported loss of offsite po~er until March 3, 1980:

Thi_s 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 w~re set to ze~o.)

5.

The data of Table 4 was re-plotted as a function of age to yield failufe rates (failures/year).*

6.

The data was subjected to several,different ~rtalyses to.

determine if it could be characterized on a generic.basis.

These attempts were not generally successful 1 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 g~neri~ basis, each plant was evaluated, for each of the causes, to determine if its failure experie~ce 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.

1.

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 stanqard deviation of 3.73 failures/year..

2.

3.

There have been 85 tota~ losses of -0ffsite 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 s~andard ~eviation of 5.89 hours0.00103 days <br />0.0247 hours <br />1.471561e-4 weeks <br />3.38645e-5 months <br />.

4. *The mean time to partial recovery (from a total.lo.ss 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 />..

5.

The ~uration 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 />.

6.

An attempt was made to obtain a least ~'1uares fit of the mean valv! of the time of outage vs. the percentag~ of offsite power l OS t ( % lines).

No SU.Ch fit was achieved (confidence level was less than 95%).

7.

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 />.

8.

The mean voltage drop is 8.98% with a standard deViation of 15.21.:.

9.

The mean frequency drop is 3.42 Hz with a standard deviation of 5.64 Hz.

10.. The mean frequency decay rate is l.42 Hz/sec with a standard deviation of 1.84 Hz/sec.

11.

The Dresden Units 2&3 reported the mos.t significant annual failure rates as noted below:

..... e.*

(a) Total failu~e rate 17.17 vs.a target of 13.47,

{b) Cause O failure rate 4 vs.a target of 2.97,

. ( c)

Cause 7 failure rate 0.67 vsia target of 0~63,

. {d)

Cause 9 f~ilure rate 3 v~ a target of 2:3a, (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 tatget of 1:67, (h)

Ca us~ 22 failure rate 3.83 vs. a target of 2.*84, and

( i) Cause 42 failure rat~ 0.17 v~ a target of -0~13.

12. Palisades has exhibited the s~cond larg~st number of target violations.

These are:

(a)

Cause 4 failure rat~ 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)

Ca~se 14 fai1ur~ rate of 0.23 v~. a target of 0.1, and (e)

Cause 29 fail~re rate of 0.93 vs. a.target of 0.45.

13. Pilgrim 1 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 failure rate of 0.25 vs. a target 6f 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 Poi~t* 3 had 3 target violations.

15. Turkey Point 4 had 2 t~rget violations.

16.

All other correspondents have had one or fewer target violations.

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..* e Conclusions l..

The loss of offsit~ power r~te is 2.29 failures/reactor year fOr ~

partial loss arid 0.24 failures/reactor year for total loss.*

2.

The Dresden and Pali~ades stations should be furth~~ evaluated to determine the causes for the target violations and to detennine

• 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 J.* Pursue the evaluati6n of Dresden 2 and Palisades~

2.

Obtain the data from the plants listed 1n Table 2.

• Data tables and resulting tomputer generated analyses are available*

from the author upon request..

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• TABLE 1

. REQUEST FOR ADDITIONAL. INFORt-lATION A.

For losses of offsite power where less than all offsite power was*

lost:.

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How many circuits to tlie offsite.network are nonnally availa.ble

• and how many w~re lost during the event?

2.

What was the cause of the event?

3.. Why did the other lines n6t fail when Some did fail?.

4.

Was any voltage increase or decre~se 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:

1.

How long was the*Power off?

How long for partial recovery?

. Please give details.

2.

If turbin~ trip occurred, how soon after did loss of offsite power occur?

3.

If power was retovered promptly (10 minutes or less), was it d0e 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, voltages 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 operati6n, etc.

6.

Date of Event.

C.

Were there any dther loss of offsite power ev~nts other than we have listed? If so, please give details of each event.

TABLE 2 PLANTS NOT PROVIDfNG THE DATA REQUESTED IN TABLE 1

• ORB#l

. 50-305 Kewaunee 50-338 North Anna-1 50-261 H.B. Robinson 2 50-230 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 Main~ Yankee 50-313 Arkansas l

• . 302.Crystal River 3 50-346 Davis-Besse l 50-269. Oconee l.

50:..270* Oconee 2 50-287

• Oconee 3 50-312 Rancho Seco 50-28~ Three Mile Island l 50-320 Three Mile Island 2

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' 4 5

7 9

10

, l 12 13 14 15 20 22 23 24

25.

28 29 31..

32 32 34 35 36 42

• TABLE 3

• Cause Not reported Unknowri Fai lur1!. in an instrument inverter with a second channel bypassed *.

• Turbine g~n~rattir voltage regulator failure.

Manual scram Circuit breaker trip during relay testing, improper yard switching operations,* improperly set relays, maintenance errors, relay testing errors, test eq1,1ipment failure, CT failure, maintenance outage~..

• Ground fault with or without protective relaying failure or with or without manual ~cram, bolted faults Protective relay failure Insulator failure (lightening arrester, transmission*line insulator, 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 s tonn Breaker failure Li ghten.i ng System undervoTt~ge Transformer winding failure Forest fires L5ghtening with breaker failure Construction activities.

Summer storm Systerr: collapse False relay operatiori 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 hittina pole System imballance

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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

.., 6. 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., 2*

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. Isl and 2 2.91 237 Dre.sden 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 CaJ vert Cliffs 2 4.09.

249 Dresden 3' 6.0 321 E. I. Hatch 1 2.43 250 Turkey Point 3.

6.01 324 Brunswick 2 4.94 251

• Turkey Point 4

6. 01 331 Duarie Arnold

. 254 Quad Cities l 4.52 333

-Fi tzPa trick 1.42 255 Palisades

. 8. 66 334 Beaver Valley 1 2.89 259 Browns Ferry l 5.92 335 St.Luciel

. 2;8 260 Browns Ferry 2 5.92 336

• Mi 11 stone 2 3.87 263 Monticello 8.96 344 Trojan 3.88

.. 255 Quad Cities 2 4.52 348 Farley l 2.46 266 PointBeach 1 9.07 409 Lacrosse 9.12 271 Vennont Yankee 7.84 272 Sa 1 er.i l 2.84

. 277 Peach -Bottom 2 5.8