ML19317E181
| ML19317E181 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 05/23/1973 |
| From: | Thies A DUKE POWER CO. |
| To: | Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| Shared Package | |
| ML19317D586 | List: |
| References | |
| 730525, NUDOCS 7912170120 | |
| Download: ML19317E181 (4) | |
Text
-
l Q
I f
i DUKE POWER COMPANY
{
)
Powra Betz.orNO
(
4aa SouTu Cuunca SrazzT, CuAar.oTTz, N. C. asaos
/w P. O. Box 217e A. C THIES SENeon VICE P=EsactNf PRODUCTION AND TR ANShA SSSIOM May 25, 1973 Mr. Norman C. Moseley, Director Directorate of Regulatory Operations Region II, Suite 818 230 Peachtree Street, Northwest Atlanta, Georgia 30303 Re:
RO:II:RFW 50-269/73-4
Dear Mr. Moseley:
Your letter of May 8,1973, which transmitted RO Inspection Report No.
requested that we review this report to determine if any 50-269/73-4, We have information contained therein is considered to be proprietary.
been informed by Babcock & Wilcox that two items in DETAILS I contain Disclosure numbers which may be used to derive basic design information.
to the public of this infor=ation may jeopardize B&W's co=petitive These numbers appear in Item 3 on Pages I-2 and I-3 and It is requested that the underlined numbers be position.
Item 8 on Page I-6.
withheld from public disclosure.
Very truly yours, l
A. C. Thies ACT:vr Attachment 0
\\b
'O 01Q\\
~
~~
m
?U'h%g RO Rp t. No. 50-269/73-4 I-2 2.
General The inspection of April 11 and 12,1973, was conducted to determine that the prerequisites for initial criticality had been fulfilled.
The inspecticn of April 17 through 20, 1973, was to review the prerequisites for initial criticality which had not been co:pleted earlier, review the collection and interpretation of physics data, and witness the initial approach to critical to evalua te adherence to requirements specified in the technical specificati"ns, codes, procedures, FSAR, and other applicable documents.
3.
Initial Criticality Initial criticality of Oconee Unit 1 was achieved at 12 :15 p.m. on April 19, 19 7 3.
Initial criticality was achieved at a boron concentration of about 1340 pom with all control rod groups withdrawn with the exception of group 7 which was 25% withdrawn.
The all rods out critical boron concentration was 1402 peu co= pared to the predicted 1334 t 100 ppm.
The reactor coolant system (RCS) was at 2500F and 600 psig ana two reactor coolant punps (one in each loop) were operating.
The RCS boron concentration prior to the start of dilution for the approach to critical was 2124 ppm.
Baron dilution began at 6:30 p.m.
on April 18, 1973, at a flow or approximately 70 gpm. The feed and bleed flow rate was reduced to 40 gpm f or dilution be? aw 1452 com.
l Reactor coolant samples were obtained every 30 minutes and analyzed for boron concentration, while the boronometer indicated the RCS i
boron concentration continuously.
The sa=ple results were l
reported to the control room approximately 30 minutes af ter the l
samples were taken.
The nuclear instrumentation source range channels were observed to be
. responding to the increase in neutron flux.
The flux count rate was
' stabli:ed at approximately 30 cps af ter achieving initial criticality. _
The inter ediate range channels were observed to come on scale when 3
the two source range channels were indicating approxi=ately 5 x 10 cps, confirming that a 2-3 decade overlap existed between the source and intermediate range channels.
The approach to criticality was conducted in a safe and orderly
=anner and in accordance with applicable procedures, the FSAR, technical specifications, and license require =ents.
N
.e.
ee
n
. 44.
RO Rpt. No. 50-269/73-4 I-3 The inspector verified that the limits and precautions, the pre-requisite tests, the required unit status,~and the prerequisite c
system conditions as specified in TP-710/1, "Zero Power Physics Test," (the controlling procedure for the initial approach to critical) were met.
The steps in the procedure were signed off as they were completed and changes to the procedure were made as described in DPC's operationea quality assurance manual.
In addition, the inspector verified the following:
a.
The starting neutron count rate was about two counts per second.
o.
The signal to noise ratio was greater than two.
c.
The high flux trips had been reset to.5 percent of full power.
d.
The discriminator and high voltage were set to the proper values as deter =ined by calibration procedures, and the enbincts were locked.
e.
The source range flux instru=ents responded to a neutron source check.
f.
The startup checklists had been completed.
g.
Precritical tests had been completed.
b.
Control rods were operable and drop times were within technical specification li=its.
Two independent plots of inverse cultiplication versus beron concentration were =aintained during the deboration and rod vithdrawal.
Five-=inute counts were made on each source range detector. The inverse cultiplication plots had a " knee" in the curve at approxi=ately the =id-point.
This occurred at a boron concentration of approxi=ately 1450 com.
The angle of the inverse multiplication curve below the knee and the delay experienced in ob taining the RCS boron sacple analysis results reduced the effectiver.2ss of this technique for predicting the point the reactor would achieve initial criticality.
This was discussed in the manage =ent interview and in a phone conversation with the plant superintendent on April 24, 1973, the inspector ider.tified this as an unresolved item.
DPC's actions, to =ake the inverse multiplic: tion plce-a more useful tool to aid in the startup of other reactors, will be reviewed during the next inspection.
q
. q'
.R0 Rpt. Ho. 50-269/73-4 I-6 11 7.
Resolution of Violation of Technical Specification 6.1.2.1 The inspector reviewed the minutes of the SRC and verified that e
test procedure TP-800/5, " Reactivity Coefficients at Power," had been reviewed and approved by the SRC.
This previously identified enforcement matter is now closed.
3.
Racetor Coolcnt Puco Flow The reactor coolant pump flow was ceasured with the core in place per procedure TP-200/12, " Reactor Coolant Pump Flow Test."
The test acceptance criteria was cat except for the maximum flow at 2155 psig and 5000F with four pumps running.
B&W's evaluation letter states:
"The acceptance criteria for four pu=p operation at 500 F was 147.2 x 106 lbs /hr maximum.
This nu=ber is based on the 'end of life' (EOL) spring constant of the fuel asse=bly holddown springs and did not reflect the removal of the orifice plugs.
" Removal of the orifice plugs increases the EOL criteria to 149.2 x 106 lbs /hr.
Using the 'beginning of life' holddown spring constant increases the criteria to 151.8 x 106 lbs /hr.
"As measured flow at this condition was 150.8 x 106 lb s'/hr,
the acceptance criteria for beginning of life has been =et.
" Flow measurement capability wiil be refined by the 40% power heat balance.
Data from the test should be re-evaluated at that tice to determine whether or not the EOL critieria has actually been exceeded.
Corrective action will be deter =ined then, if required."
'This was discussed during the managccent interview.
DPC indica'ted this caresolved item will be re-evaluated at the 40% power level.
l.
During a subsequent conversation with the plant superintendent l
(on April 30, 1973), the inspector was informed that toth 36W sad DPC agree that a core =caningful cvaluation can be made af ter test data are obtained at 75% of full power.
They plan to make their evaluations at that power level.
1/ See R0 Inspection Report :io. 50-263/73-3, Details I, paragraph 3.
..