ML19312B832
| ML19312B832 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/11/1976 |
| From: | Parker W DUKE POWER CO. |
| To: | Rusche B, Schwencer A Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19312B833 | List: |
| References | |
| NUDOCS 7911250045 | |
| Download: ML19312B832 (4) | |
Text
NssioN INRC PoRu 195 u.s. Nuctsam nacutAroR y co m -
ER 6-2 70/287 v2.m NRC DISTRIBUTION FoR PART 50 DOCKET MATERI AL TO:
FROM:
DATE OF DOCUMENT Duke' Power Company 6/11/76 Mr. Benard C. Rusche Charlotte, North Carolina oATE RECEivEo Mr. William O. Parker, Jr.
6/17/76 N ETTER INOTORIZ E D PROP INPUT FORM NUMBER OF COPIES RECEIVEo RIGIN AL UNC LASSI FIE D OCo*v Three signed DESCRIPTION E N CLOSU RE Ltr. notorized 6/13/76 re o'ur 1/30/76 ltr....
trcus the following:
Andt. to ol/ change to tech spec consisting of request to revise the flux / flow trip setpoint
- for unit 1 as well as incorporating a surveillance testing requirement for the internals vent valves.
gg PLANT NAME:
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Oconee 1-2-3 SAFETY FOR ACTION /INFORMATION ENVTRO 6/18/76 RJL l
____ ASSIGNED AD:
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Schwencer (S)
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June 11, 1976 3
Negulatory 0ocket Filee>$ WO'%m'h
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M 2 7 Mr. Benard C. Rusche, Director 0
M.,lejry b/ci h Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission C
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Washington, D. C.
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Attention:
Mr. A. Schwencer, Chief 0%[
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Operating Reactors Branch No. 1
)gg1Nh Re:
Oconee Nuclear Station 6
Docket Nos. 50-269, -270, and -287 O
s#5*ES
Dear Mr. Rusche:
,a Pursuant to 10CFR5L. ;50.90, Duke Power Company hereby requests -
9 change in the Oconee Nuclear Station Technical Specifications.
The~
proposed change consists of revising the flux / flow trip setpoint for Oconee Unit 1 as well as incorporating a surveillance testing require-ment for the internals vent valves.
In the past the core thermal-hydraulie analysis, including the flux /
flow trip setpoint analyses, for Oconee Units 1, 2 and 3 included a core flow penalty for an assumed stuck open vent valve.
By letter of January 30, 1976, the Commission provided for elimination of the core flow penalty for an assumed stuck open vent valve by instituting surveillance testing on the vent valves during each refueling outage.
Accordingly, to permit elimination of the vent valve flow penalty, a technical specification requiring surveillance testing of all internal vent valves during each refueling outage is proposed.
This surveillance testing will confirm that no vent valve is stuck in an open position and that each vent valve exhibits complete freedom of movement.
In the case of Oconee Unit 1, which has commenced Cycle 3 operation, the surveillance testing of all vent valves has been satisfactorily performed during the end-ef-Cycle 2 refueling outage.
The existing flux / flow trip setpoint is, however, based on an analysis that included a flow penalty for an assumed stuck open vent valve.
A re-analysis of the flux / flow trip setpoint has been performed without including the vent valve flow penalty but including the other conservative assumptions 44 and allowances:
610L l
Mr. Benard C. Rusche Page 2 June 11, 1976 (1) a steady-state power level of 108 percent (indicated power level of 102 percent plus 6 percent uncertainty in power level measurement),
(2) design power peaking factors and hot channel factors, (3) a conservative value for the trip delcy time, i
(4) mnvimum effect o f fuel densification on DNBR, (5) an allowance for errors in the coolant inlet temperature and system
- pressure, (6) a 5 percent reduction in hot assembly flow to account for flow maldis tribution, (7) a reactor coolant system flow rate of 107.6 percent of the original I
design flow rate (as compared to the measured flow values of 108.6 percent for Oconee 1), and (8) a conservative allowance for core bypass flow through control rod i
and instrument guide tube, core shroud, etc.
The flux / flow r2tio resulting from this calculation was further reduced by 1.5 percent for flow signal ncise and by 1.2 percent to account for the precision of the various components in the RPS flow tastrument string (a transmitter, summer amplifier, function generator, and bistable comparator) and yielded a flux / flow trip setpoint of 1.08.
However, a flux / flow trip setpoint of 1.07 is proposed to provide additional safety margin.
In the case of Oconee Units 2 and 3, the existing flux / flow trip setpoints are based on analyses that included the v nt valve flow penalty; however, future analyses will exclude this penalty.
Enclosed are replacement pages for the Oconee Nuclear Station Technical Specifications incorporating these proposed changes.
The proposed changes are identified by vertical lines in the margins of the replacement pages.
Forty (40) copies of this request, including three signed originals, are enclosed.
Ve truly yours, 3
J l' T
,/shra2.l._[h.
William O. Parker, Jr.
PMA:vr Enclosures
/
Mr. Benard C. Rusche June 11, 1976 Page 3 WILLIAM 0. PAIUER, JR., being duly sworn, states that he is Vice President of Duke Power Company; that he is authorized on the part of said Company to sign and file with the Nuclear Regulatory Commission this request for
', amendment of the Oconee Nuclear Station Technical Specifications, Appendix A
!to Facility Operating Licenses DPR-38, DPR-47 and DPR-55; and that all stat uts and matters set forth therein are true and correct to the best of s knowledge.
i 8,
n2 William O. Parker, Jr., V g President ATTEST:
/
j
/
John C. Goodman,'Jr.
y Assistant Secretary Subscribed and sworn to before me this lith day of June,1976.
Notary Public My Commission Expires:
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