ML20041A116
| ML20041A116 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 02/12/1982 |
| From: | Parker W DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8202190118 | |
| Download: ML20041A116 (4) | |
Text
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DUKE POWElf COMPMY Powen llenmixo 422 SouTn Cnuncu Srnr.r.r. CnAnw?TE, N. C. aaaaa WI L LI AM O. PAR M ER, J R.
v.cr e...oro, February 12, 1982 n u,,,o.,ct,y 70.
Strane Pnoouctions 373-4083 Mr. Harold R. Denton, Director CD Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission S
Washington, D. C.
20555 IlECE!VED Attention:
Ms. E. G. Adensam, Chief D
FEBImgg2>.3 Licensing Branch No. 4 gy,%
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Enetreams M
Re: McGuire Nuclear Station
$f Docket Nos. 50-369, 50-370
'Ig s,
I vg, e.r
Dear Mr. Denton:
My letter of December 29, 1981 described Duke Power Company's plan for the operation of McGuire Unit 1 in light of the problems identified in two foreign plants with Model D steam generators. The technical justification for this program was provided in my letter of January 26, 1982.
In that letter we outlined the plan for operation of Unit I through February 15, 1982 and demon-strated that the technical specification criteria for steam generator tube plugging, using a very conservative analysis, uould not be exceeded.
As you are aware, since that program was defined Oconee Nuclear Station -
Unit I was shutdown on February 9, 1982 with a steam generator tube leak.
On February 11,1982 Unit 3 at Oconee developed indicatirn of a tube leak although at present is still operating. Both of these events have forced a re-evaluation of the McGuire Unit 1 operating plan. The plan for McGuire is to continue operation of McGuire Unit 1 through February 22, 1982 which is a one week extension of our original schedule. The analysis that was done to verify the acceptability of operation through February 15, 1982 was examined and updated to consider operation through February 22, 1982. This analysis is presented in Attachment 1.
The reasons for the decision to keep McGuire operating for an additional week are twofold:
(1) Manpower limitations, and (2) Potential for power shortages.
Duke Power Company contracted with B&W to perform the eddy current testing at McGuire. They performed the baseline inspection and the eddy current testing (ECT) in November and December after operation at 50% and 75% power. The availability of qualified people from B&W to. perform the eddy current at McGuire is limited. The following events have transpired in recent weeks, all of which involve the services of the same B&W non-destructive testing (NDT) personnel:
- 1) Steam generator tube rupture at Ginna
- 2) Makeup line leak at Crystal River 0
- 3) Oconee - Unit I steam generator tube leak'
- 4) Oconee - Unit 2 inservice inspection f
- 5) Oconee - Unit 3 leaking tube - (potential involvement)
- 6) McGuire - Unit 1 eddy current testing, Model D steam generator 8202190118 820212 0500036
] DR ADOCK
t Harold R. Denton February 12, 1982 Page 2 It was deemed necessary that B&W perform the eddy current examination on McGuire since they had performed the previous inspection. Additionally, the have worked closely with Duke Power Company in developing eddy current techniques to increase the sensitivity for detection of tube wear indications seen on foreign Model D steam generators. Additionally, the technical and quality assurance personnel in the Duke Power Company General Office who normally support unit outages for steam generator /NDT related work would have difficulty supporting ontage work on all three Oconee units (assuming Unit 3 is forced to shut down) and McGuire Unit I simultaneously.
Duke Power Company's system production capabilities are outlined below.
9144 Mw - System capacity w/o McGuire and Oconee (includes 380 Mw miscellaneous reduction) 9714 Mw - System capacity with McGuire @ 50% and w/o Oconee 9982 Mw - Forecast peak for February 9217 Mw - Maximum peak experienced in February to date 536 Mw - Spinning reserve requirement Peak load projection for February 15, 1982 assuming a low temperature of 300F is 8800 Mw.
Adding the spinning reserve requirement of 536 Mw means that total system generation including purchases must be 9336 Mw to meet this demand.
This could not be met without McGuire. More important, the potential for cold 0
weather in February still exists. Assuming a low temperature of 20 F, fore-casted load is in the 9400 - 9500 Mw range. With a low of 150 projected load is 9800 - 10,000 Mw.
With McGuire on line at 50% power, system capacity is 9714 Mw which should enable Duke to meet load demand and reserve requirements for the next w ek.
In summary, it is Duke Power Company's position that operation of McGuire Unit 1 through February 22, 1982 is justifiable for the reasons outlined above and will not result in any adverse safety consequences as described in Attach-ment 1.
Please advise if there are any questions regarding this matter.
I Vdry truly yours,s
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William O. Parker, Jr.
GAC/jfw Attachment
l s
n Harold R. Denton
' February 12,' 1982 Page 3 cc:
Mr.
P.' R. Bemis Senior Resident Inspector McGuire Nuclear Station
'Mr; James P. O'Reilly, Regional' Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta,' Georgia 30303 r
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McGuire Nuclear Station Steam Generator Wear Evaluation for Operation through February 22, 1982 Outlined below la a refinement of the calculation for the maximum tube wear on the single worst tube at McGuire for the operating period 1/1/82 - 2/15/82.
This revised calculation is based on a more accurate determination of the num-ber of days that we have operated or plan to operate at each power level prior to shutdown.
The wear rates used in the calculation below are identical to those used in our submittal of January 26, 1982.
For the period 1/1/82 - 2/15/82 Days Power level Wear rate (%/hr)
Total wear (%)
36 50%
.023 19.87 5
75%
.d52 6.24 4
90%
.061 5.86 1
100%
.0727 1.77 33.74 the total remaining wear available prior to reaching the tube plugging limit of 40% is 6.3%.
Operation at 50% for an additional 7 days would result in additional calculated wear of 7(days) x 24(hrs.) x.023(%/hr.) = 3.86%
When this value is added to the calculated wear through February 15, 1962 33.74 + 3.86 = 37.6%
the result shows that the technical specification criteria are not exceeded.
Described below is the basis for the wear rate values used above to emphasize the conservatism included in this calculation.
1.
The wear rate values for 50% and 75% power are based on the actual operation of McGuire and the eddy current inspections previously reported to NRC.
- However, these wear rates have been calculated independently of each other (no credit is taken in the 50% rate for the days spent above 50%).
The basis for detectability of the wear by eddy current is a 10% threshold, which we have established through laboratory testing as a conservative threshold number.
2.
The weer rates for 90% and 100% power are based on the single leaking tube at Ringhalc because eddy current data for McGuire are not available for these operating power levels.
These wear rates are conservative because they assume that no wear occurred prior to reaching that power level and that the wear rate did not increase at power 1cvels higher than the given power level. Wear rates calculated in the same manner from the Ringhals operating data for 50% and 75%
power have been shown to significantly overpredict wear at McGuire, based on our previotts inspections.