ML19257C453

Contention 46 Alleging That Transient Caused by Control Rod Drop Under High Xenon Conditions Constitutes Health & Safety Hazard Due to Loads Placed on Reactor Sys.Contains Supporting Statement on Timeliness

ML19257C453
Person / Time
Site:	Allens Creek File:Houston Lighting and Power Company icon.png
Issue date:	01/08/1980
From:	Doherty J DOHERTY, J.F.
To:	Atomic Safety and Licensing Board Panel
References
NUDOCS 8001290150
Download: ML19257C453 (3)

Text

UNITED STATED

• OF AMERICA @WAM 8fW s

NUCLEAR REGULATORY COMMISSION sA,, -

BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of S S

HOUSTON LIGHTING & POWER COMPANY S Docket No. 50-466 S

(Allens Creek Nuclear Generating S Station, Unit 1) S

-s .. - ,. . .

JOHN F. DOH2RTY'S ColiTENTION #46

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John F. Doherty, Intervenor in the above Construction License proceeding files this Contention J46 and supporting statement on timeliness.

This Intervenor contands control rods capable of causing a five second period on being withdrawn one notch, if uncoupled from their drives and stuck in the core could, by falling several notches moments le ;er cause a significantly shorter period leadinc to fuel damage. The core conditions necessary for fuel damaging short periods such as these are three:

1- when there is high renon concentration in the reactor core (High xenon concentration magnifies the worth of certain central control rods until burned-off),

2- moderator temperatures are.high (200 F 480 0 F), and 3- the percentage of voids in the coolant was greatly re-duced.

The ACRS in UUREG-0572 " Review of Licensee Event Reports (1976-8),"pg D-4 has called for a study of fuel damage caused by a dropped rod of high notch worth caused by high xenon core conditions. This group also suggests the withdrawal of a pre-scribed rod whose worth has been multiplied by core renon AS '

concentrations as high as.O.5%6K/Khat Monticello, on 2/23/79 according to I.E. Circular 77-07, may be more probable than a rod withdrawal error under normal scart-up conditions. Hence, ACRS questions that the rod vithdrawal error is a more serious accident than the rod drop accident under high core xenon.

This.came ACR3 report indicates there have been 13 rod separation events since January of 1976, but none of these have occured with a high notch worth ~ rod under high ~xeno'n ' con-ditions,t , This good fortune.is not due to design 1832 356- 3 00,29 o ja

TWO ..y however. . .

Moreover, xenon spatial stability decreases"kithiincreased reactor size.(See: APED-5640 " Xenon Cbnsidsration'in Design of Large BWRds", R. L. Crowther, June, 1968)$ ACNGS with its 238 inch core diameter is lar 1ne than all plants 'that have exper-ienced the five second or less reactor periods when a high notch worth rod was moved a single notch.

This Intervenor contends that a transient caused by a ,

control rod drop under high xenon _ conditions constitutes a hazard to his health and safety because the loads placed on the reactor system are unknown at this time.

Succortine Statement on Filine Timliness This Intervenor maintains he has not delayed in filing this contention 46. Although the problem was noticed as early as 1977,I. E. Circular 77-07, offered a solution to the problem.

Only recently has it become clear to the Division of I. and E.

that the solution was unsuccessful. However, only the ACRS study published in UUREG-0572, has considered the accident implications of Rod Drop under these special core conditions.

Their study was not available until October 25, 1979, to this Intervenor, too late for inclusion in the pre-hearing conference.

This Intervenor knows of no other means to bring this acci-dent possibility to the attention of the NRC, where he will be able to argue for its consideration in a licensing where his health and safety interests are concerned.

This Intervenor has raised several accepted safety conten-tions and is researching collateral items to this. He may be reasonably expected to produce a witness or other evidence on this issue, because of his callateral issue's activity.

No other party has raised this issue.

This issue will broaden the scope of the proceedings because it is new, significant particularly to a large core BWR such as ACNGS, and attention to tho issue in these proceedings will pro-vide useful information to the several licensings for BWRs of smaller core size. 3s u7

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THREE This Intervenor urges that based on a balancing of the five factors of 10 CFR 2.714 this contention should not he barred on lack of timeliness. -

Copies of " JOHN F. DOHERTY'S CONTENTICII #46" have been served on the following parties by First Class U. S. Postal Service ,

this @ January, 1980.

Respectfully Submitted, wY0>

John F. Doherty Sheldon J. Wolfe, Esq. (NRC) Janes M. Scott (TexPIRG)

Dr. E~ Leonard Cheatum (URC) Clarence Johnson (requested)

Gustave Linenberger (URC) Brenda A. McCorkle, Esq.

Carro Hinderstein, Esq.

Steven M.Gooch, R. Gordon Sohinki, Esq(.

Esq. (Staff)

Applicant) David Marrack, M. D.

J. Gregory Copeland, Esq. (Applicant) Wayne Rentfro Richard A. Lowerre, Esq. (Texas) 1832 358