ML20056E455
| ML20056E455 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/18/1993 |
| From: | Hampton J DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9308240077 | |
| Download: ML20056E455 (11) | |
Text
Il I
Duke 1buer Company J. W. HArtun Oconee Nuclear Site
\\ke Pmsident PO Bax ilt9 (803)M534990thce Seneca. SC3%i9 (803)M53%4 Fax DUKEPOWER August 18, 1993 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555
Subject:
Oconee Nuclear Site Docket Nos. 50-269, -270, -287 Inspection Report 50-269, -270, -287/93-20 Reply to Notice of Violation Dear Sirs By letter dated July 20. 1993 the NRC issued a Notice of Violation as described in Inspection Report No. 50-269/93-20, 50-270/93-20, and 50-287/93-20.
Pursuant to the provision of 10 CFR 2.201, I am submitting a written response to the violation identified in the above Inspection Report.
Very truly yours, f
7 J. W. Hampton f
cc:
Mr. S. D. Ebneter, Regional Administrator U. S. Nuclear Regulatory Commission, Region II Mr. L. A. Wiens, Project Manager Office of Nuclear Reactor Regulation l
Mr. P. E. Harmon Senior Resident Inspector Oconee Nuclear Site j
.'. '4 0 3 C
v-p
/
?
f 9308240077 930818 E
8 PDR ADOCK 05000269 is G
PDR lhenext on recycw gxper-
1 l
Violat' ion 269.270.287/93-20-03. Severity Level IV Oconee Technical Specification 6.4.1 requires that the station be operated and maintained in accordance with approved procedures.
Operating Procedure OP/1/A/2000/041, Keowee - Mode of Operation, Section 2.3 requires the Keowee generator load to be no greater than 60 megawatts.
This restrictive change was effective on January 15, 1993, to resolve possible overspeed trip concerns.
Administrative Policy Manual for Oconee Nuclear Station, Section 4.2.6, and Station Directive 2.2.1, Station Procedures, Section 5.0, require major procedure changes to be prepared, reviewed and approved prior to implementation.
Contrary to the above, these requirements were not met in that on June 2, 1993, l
the maximum operational load requirements for Keowee were changed and implemented by internal memorandum in lieu of an approved procedure change. Furthermore the maximum analyzed load was exceeded for short periods of time on several occasions.
I
RESPONSE
1.
The reason for the violation, or if contested, the basis for disputing the violation:
The reason for this violation is that Oconee and Keowee Operations personnel did not provide the Keowee Operators with the proper guidance for the new limits provided by Design Engineering in the resolution of PIR 0-093-0041.
This is considered a Management Deficiency.
The resolution of PIR 0-093-0041 provided the Keowee Operators with a new limit of 75 W e.
The ability to operate at this limit was dependant on a function of Lake Keowee and Lake Hartwell pool elevations.
Oconee and Keovee Operations requested that Design Engineering provide a margin of error, conservative to the actual lake level limits, to allow for any measurement errors in lake level determination.
Design Engineering provided this curve (see attached Operability Evaluation for PIR 0-093-0041).
Ilowever, no margin was requested or incorporated to allow for Keowee Hydro governor drift above 75 W e.
Consequently, when the Keowee Operators set the generator at 75 We, governor drift caused the generator output to slightly exceed 75 We on occasion. This failure to account for the governor drift is the root cause of this incident.
The Keowee Operators should have been instructed to set the generator up at some output less than 75 We to account for governor drift.
The inspection report references the controlling operating procedure, OP/0/A/2000/41.
The 60 We limit referenced in this procedure was j
incorporated as a " restricted change". This restricted change was valid j
until the resolution of PIR 0-093-0041.
Calculation 050-6003 (Rev. 1) provided new limits that superseded the guidance in the restricted change, therefore the restricted change that incorporated the 60 We limit was technically " expired" and no longer valid (reference Operations Management Procedure 1-9, Section 8.5).
The expiration of a restricted change does 1
4 i
NRC Vi'olation Response 93-20-03 Page Two not require the review and approval process characteristic of normal procedure changes because the condition of the expiration is previously evaluated when the restricted change is issued.
During the investigation into this
- incident, two administrative discrepancies were found associated with the implementation of new load limits of calculation 0S0-6003. First, the expiration of the restricted procedure change associated with the 60 MWe limit was not properly documented per OMP l-9, Section 8.5 (C).
Also, as mentioned in the inspection
- report, the Keowee Modes of Operation procedure (OP/0/A/2000/41) was not revised in a timely manner to incorporate the new limits specified by OSC-6003.
Also associated with this violation, the inspection report references a review of operational data from May 1 through June 15, 1993.
The inspection report notes that the Keowee Unit generating to the grid occasionally exceeded 60 MWe; the limit specified by procedure OP/0/A/2000/41.
During this period, the Keowee Operators set the generatcr up for 60 MWe or less (as required by procedure) and governor drift caused the units to occasionally exceed 60 MWe.
In this case, Keowee Operations anticipated the potential for governor drift and established a conservative margin of 6 MWe from the absolute limit (66 MWe). At no time (except for special testing on April 5,1993) was the 66 MWe limit exceeded.
Since the Keowee Operators have other 4
responsibilities and cannot continuously monitor generator output, the intent of the 6 MWe margin was to ensure governor drift never exceed the absolute limit of 66 MWe. This strategy was effective but overlooked when i
the limit was changed to 75 MWe.
2.
The corrective steps that have been taken and the results achieved:
Keowee Operations has incorporated a margin of error into the 75 MWe limit.
The Keowee Operators are now restricted by procedure 4
OP/0/A/2000/41 to set the generator up at 70 MWe or less to ensure the absolute limit of 75 MWe is not exceeded in the event of governor drift.
Also, the restricted change which placed the 60 MWe limit on the generators, has been properly documented as expired.
4 3.
The corrective steps that will be taken to avoid further violations:
The corrective actions addressed in Item 2 should prevent further incidents.
4.
The date when full compliance will be achieved:
Duke Power Company is in full compliance.
2
c
\\-
i Revision 1 OPERABILITY EVALUATION Station: Oconee Unit: 1 2 3 PIR Number: 0-093-0041 Structure, system or component (SSC) in question:
Keowee Hydro Station Design basis references applicable:
OSS-0254.00-00-2005 Technical Specification sections applicable:
3.7
$$$M $ $ W Y M5?NN&
The SSC in question is recommended to be:
OPERABLE X
CONDITIONALLY OPERABLE INOPERABLE operability Evt.luation expiration date N/A I
FSAR change required Yes X
No 10 CFR 50.59 Evaluation required X
Yes No Summary / Comments:
This PIR addresses a potential problem where, if a Keowee hydro unit is generating to the grid at full load with a high head and a Design Basis Event occurs, excitation for that Unit could be lost, making the Keowee Unit not available for oconee.
Excitation is lost due to tripping the field breaker as a result of overspeed caused by load rejection. The overspeed switch is set for 180 rpm.
Load rejection Tests performed on 4/6/93 (TT/0/A/0620/03) document that a Keowee unit generating at 75 MW with a gross head of 134.9 feet will reach a maximum overspeed of 172.23 rpm. Calculations have been performed to determine the maximum load rejection speed at other gross head conditions. The results of these calculations are curves of acceptable conditions for power levels up to 75 MW.
With Keowee generating to the grid within the range of the attached curves, the unit will not exceed the overspeed set point.
This conditional operability shall continue until a permanent resolution is provided.
Calculation OSC-6003 Rev. 1 details, documents and supports the above findings.
originated by: _
Date:
Reviewed by:
II'/
- N Date:
m Approved by:
Date:
l
t 1
75 Mw Keowee Operating Chart 673 672 671 670 l
669 f,
Urmcceptabe Operaling Region 668
-E I
_ 667
.> 666
.3 665 664
/
/
% 663 it
,/
' ~
5 n.W
'~
662 661
' d O
660
, 'i,7 e
~
659 658 ll 657 656 j
655 I,
a
- l 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 Keowee Lake Level (ft)
- \\.
i
- i i
1
t 74 Mw Keowee Operating Chart 673 672 671 670 Unacceptable Operating Regk>n 668 667 8
f l
I 666 3
y e 665 S',
f 664
/
^
663
. iT) f t%2 gg{[' _,,.
i b %'
,7gf
660
/',
'7 659 y
658 --
657 656 Acceptable Oporating Region 655 785 786 787 788 789 790 791 792 793
'794 795 796 797 798 799 800 Keowee Lake Level (ft)
-+
L 73 Mw Keowee Operating Chart 673 672 -
- i 671 670 g
669 i
Unaoceptabe Operatino Regbn f
S 667 --
To j666
- ya,f/n e 665 --
f r
DN
~
664
?,663 9L2? '
E 662 -
f',-
$681 660 n'
659 658
~j.
657-ae rafg Nm 656 655 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 Keowee Lake Level (ft) e v
.f 1
0 E
08 9
97
/'
8 m
97
/
79 7
/
iu u
v b
6 l
9 E
7 v
IV, i
i t
ta re 5
p 9
m O
7 a
y7 iv
'a 4
tr i
a
,[
9 w
7 h
r,
)
t w
f.
C
(
pL %
A e
l g
wi D
3 v n
e n
9 Mt c
y 7 L a
r g
e k
e a
2 p
L 2
7 O 9 e 7 e 7,_
e w
e o
w e
K o
1 9
e K
7 y
0 I
9
)
7 m
9 k
8
/
g 7
e R
g n
8 il 8
a 7
/
re p
O 7
4 8
7 ba t
f p
ec 6
K y
8 i
n 7
U 587 2
1 0 9 8 7 6 5 3 2
- 9 8 6 5 4 m6 %6 1
6 6 5 5 5 5 5 7 7 7 ' 6 6 6 6 6 6 6 6 6 6 6 6 e~
s 6 6 6 6 6 3 e g ??j&o
_c
{.
.i
\\t s
I !!I l
i._
w a
u a.
W w
0 a
0 w
8
-r y
9 w
9 s
7 e
8 97
-e 3
'w 7
9 7
/'
n w
u i
v r
o 6
p i
l 7
t 9
a.
g
/
ii w
n a
i v
5
'i p
9 7
O v
n
- e yg 4
9 w
t r
p 9
a h
7
)
t f
t m
(
C l
M A
e g
v wi 3
n e
9 Mt y
7 L v
a e
r w
r k
e 1
p a
L
+
2 7 O i
9 e
s 7 e Y
-r e
w w
/
e o
g g
w e
r K
u 1
o 9
e 7
K w
0 m
t 9
I 7
/
s um n
9 g
k 8
g 7
e i
/'
e R
g n
8 8
ta 7
w l
/
m re p
O 7
e 8
b 7
a t
pe c
6 c
i o
8 m
g n
7 U
587 1
0 9 8 7 6 5 1
0 9 8 7 s 5 4 3 2 3 2 6 6 6 5 5 5 5 5 7 7 7 7 S 6 6 e 6 6
%6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 s 6 6 i
$ }3.li%Cj8o s
4 00 8
9 97 8
97
~
79 7
69 7
5 97 tr 4
a 9
h 7
)
t C
f
(
l g
e wi n
3 v 9 e Mt a 7 L e
r e
k 0
p
/'
a L
7 O 29 e 7 e
/
e w
e o
w W
e o
K 1
e 9
y K
7 0
7 97 T'
R-98 7
no ig e
8 l
I 8
I
~
7 g
/
n ita re 7
p 8
/ '_
O 7
le b
a 6
t t
p 8
c-I e
7 c-a U-8 n
5 7
2 0 9 8 7 6 5 4 3 2 1
0 9 8 7 6 5 1
7 7 7 6 6 6 6 6 6 6 6 6 6 5 5 5 5 5 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 E g>3..g.~gc5.Eg0 n
i
b 0
0 8
9 9
7 8
97 7
9 7
~
y 69 7
m 5
9 w
7 r
w, t
u a
iv 4
r 9
h g
7
)
tf C
B
(
l g
g e
win ii 3 v e
n 9 e r
7 L c
Mt m
e a
r y
k e
G a.
y 9
p w
2 L
6 O 9
e t
t 7 e e
a w
i e
p o
.s
.e-w w
e
.v o
w K
w 1
w e
n 9
7 K
v 0
w 9
,[
7 9
8 w
Q 7
8 v
8 7
s m
m A
7 M
n 8
io 7
g e
R m
g 6
n n
8 it 7
4 a
r e
p O
5 8
le 7
a 3 2 9 8 7 6 5 4 3 2 1
0 9 8 7 6 5 b
7 7 6 6 6 6 6 6 6 6 6 6 5 5 5 5 5 tp 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 ec 2r!a e
$Cj8o canU l