ML20084S476

RO 50-254/76-31:on 760920,station Informed by GE of Error in Reload 2 Licensing Submittal in Determining Max Change in Critical Power Ratio Due to Abnormal Operating Transient. Caused by Incorrect Analysis in Preparing Submittal

ML20084S476
Person / Time
Site:	Quad Cities
Issue date:	10/04/1976
From:	Kalivianakis N, Schweitzer E COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084S480	List: ML20084S476 ML20084S483
References
NJK-76-365, RO-50-254-76-31, NUDOCS 8306170048
Download: ML20084S476 (3)

Text

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Com wIlth Edison i Ouad-Ci ies Nucf:;ar Power Station 1gpg gpJ Post Office Box 216 Cordova,lihnois 61242 Telephone 309/654-2241 e

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J. Keppler, Regional Director Office of Inspection and Enforcement Region 111 U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Reference:

Quad-Cities Nuclear Power Station Docket No. 50-254, DPR-29, Unit i Appendix A, Sections 3.2.C.1, 6.6.B.I.h Enclosed please find Reportable Occurrence Report No. RO 50-254/76-31 .

for quad-Cities Nuclear Power Station. This occurrence was previously reported to Region Ill, Office of Inspection and Enforcement by telephone on September 21, 1976 and by telecopy on September 21, 1976.

This report is submitted to you in accordance with the requirements of Technical Specification 6.6.B.l.

Very truly yours, COMMONWEALTH EDISON COMPANY QUAD-CITIES NUCLEAR POWER STATION

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/r e N. J. Kalivianakis Station Superintencent NJK/E'AS/lk cc: G. A. Abrell J[.theM 8306170048 761004 PDR ADOCK 05000254 S PDR OCT 61976

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., U UCENSEE EVENT gORT j CONTROL BLOCK:l l l l l l l (PLEASE PRINT ALL REQUIRED INFORMATION) 1 6  ;

iEE UCENSE NUM'BER PE TY 01 ll lL lQl Al Dl 1l ,l0 l0 l-l 0 l 0 l 0 l 0l 0l-l0 l 0 'l l 4l 1 l1 l1 l1l l0l1l 7 89 14 15 25 26 30 31 32 CATEGORY TV OOCKET NUMBER EVENT DATE REPO"' OATE O 1 CONT l l l [_TJ lLl l0 l 5 l 0 l-l 0 l 2 l 5 l 4l lo l9 l2 l0 l7 l 6l l1 l0 l0 l4 l7 l 6 l 7 8 57 58 59 60 61 68 69 74 75 80 EVENT DESCRIPTION 95 ion September 20, 1976 the Station was informed by General Electric Company of an error l 7 89 80 3E l In the Unit One Reload-2 Licensino Submittal in determining the maximum change in the l 7 89 80 SE l Critical Power Ratio (CPR) due to an abnormal operating transient. The Licensing l 7 89 80 3E l Submittal states that the maximum change in CPR for 7X7 array fuel is 0.23 for a l 7 89 80

@ l turbine trip without steam bypass. This value, when added to the Safety Limit l 7 89 psuuE 80 CE CODE COMPONENT CODE SUPPUER VOLATON 3E l Zl Zl W 7 89 10 11 l Z l Z l Zl Zl Zl 2l 12 17 W43 44 lZ l9 l9 l9 l 47 648 CAUSE DESCRIPTION DE l (Proximate Cause-Other) This occurrence was caused by incorrect analysis in preparing l 7 89 80 3E l the Licensing Submittal. The actual transient analyses were correct, but the wrong l 7 89 80 EE l conclusions were drawn in determining the operating Ilmit for minimum Critical Power l S  % POWER OTHER STATUS O COVE DISCOVERY OESCRIPTON 7 8 9 W 10 l 0l9 l6 l 12 13 l NA l 44

[DJ' 45 lNotificationfromG.E. Company 46 80 l

ACTMTV COMTENT RELEASEO AMOUNT OF ACTMTV LOCATON OF RELEASE DE' lz_J OF LzJ RELEASENAl l l NA l 7 8 9 10 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTON DE l Ol 0 l 0 l 7 89 11 dl12 13 NA 80 l

PERSONNEL INJURIES NUMBER DESCRIPTON DE l0l0l0l l NA l 7 89 11 12 80 OFFSITE CONSEQUENCES gg l NA l 7 89 _ 80 t

LOSS OR OAMAGE TO FACILITY l

TYPE DESCRIPTON Q] Q 7 89 l

10 NA 80 l

PUBLICITY 1 l NA l 7 89 80 ADOITIONAL FACTORS Q[ l (EVENT DESCRIPTION CONTD) Minimum CPR of 1.06, gives the operating limit for l 7 89 80 DE l Minimum CPR of 1.29 for 7X7 fuel. However, examination of the Licensing Submittal (cch9 NAME: PHONti

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ADDITIONAL FACTORS EVENT DESCRIPTION CONTD shows that the Rod Withdrawal Error (RWE) is the limiting Minimum CPR transient, and would result in a larger change in CPR than 0.23 This Is for a Rod Block Monitor (RBM) rod ' block line setpoint of 110% at rated core flow. This oversight was apparently made when determining the actual Minimum CPR limitations for Unit One Cycle 3. As given in the i'

j- License Submittal, the worst case RWE would result in a RBM rod block at 11.5 feet control rod withdraw motion (23 notches, position 46). This rod movement would give a net CPR change of 0.255 for 7X7 fuel, and a subsequent Minimum CPR limit of 1.315 This value exceeds the Technical Specification Limiting Condition for Operation of 1.29 for 7X7 Fuel.

The safety impilcations of this occurrence are minimized by the fact that the lowest CPR for Unit One 7X7 fuel was greater than 1.315 Therefore, the reactor has never been operated at a condition which could potentially cause the CPR to go below 1.06 in the event of the worst rod withdrawal error. Thus, this occurrence did not pose any threat to the safe operation of the plant, nor to the health and safety of the public.

CORRECTIVE ACTION TO PREVENT RECURRENCE in response to this occurrence, a work request was issued to lower the

Rod Block Monitor trip level from 110% to 107%. A corresponding Technical Specification change for Table 3 2-3 has also been initiated.

At a setpoint of 107%, the worst case rod withdrawal error would be blocked at 7 feet withdrawn, which would result in a maximum change in .

CPR of 0.16. This is much less than the 0.23 CPR change for the turblne trip without bypass transient, and the value of 1.29 Minimum CPR value for 7X7 fuel is now correct. The RBM setpoint change was completed on September 22, 1976 on Unit One. During the time interval between the notification of the error until the time the RBM setpoint was changed, all rod movement was suspended. There have been no previous occurrences of this nature at quad-Cities Station. The corrective

, actions taken should be adequate to resolve this occurrence.

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