ML20092M710

Thirteenth Part 21 Deficiency Rept Re Failure of Main Steam Lines Due to Main Feedwater Overfill.Initially Reported on 800319.Next Rept Expected to Be Submitted by 851218

ML20092M710
Person / Time
Site:	Bellefonte
Issue date:	06/21/1984
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-PT21-84-298-000 PT21-84-298, PT21-84-298-000, NUDOCS 8407020365
Download: ML20092M710 (2)

Text

_ _ _ _.-

So&38 g

x So 'l3'l t

r' TENNESSEE VALLEY AUTHORITY t

CH ATTANOOGA. TENNESt/ E 374ot 400 Chestnut Street 10wer II Sh pN *. N June 21r 1984

'U.S. Nuclear. Regulatory Commission Region II f

. Attn:..Mr. ' James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900-

' Atlanta, Georgia 30323 i

Dear Mr. O'Reilly:

BELLEFONTE NUCLEAR PLANT UNITS 1. AND 2 - FAILURE OF MAIN STEAM LINES i

BECAUSE OF MAIN FEEDWATER OVERFILL - NCR BLN NEB 8004 - THIRTEENTH

' INTERIM REPORT t

On March 19,1980,~ Bruce Cochran, NRC-0IE Region II, was informed that I

. the ' subject nonconformance was determinal to be reportable in accordance

-with 10 CPR 50.55(e). This was followed by our interim reports dated April 17, September 23, and December 29,1980; June 25 and December 28, 1981; March 31,' August 27, and November 18, 1982; March 24, July 14, and November 18, 1983; and February 27,.1984. Lolosed is our thirteenth interim report. We expect to submit our next report by December 18,.1985.

We' consider 10 CFR Part 21 to be applicable to this nonconformance.

If you have any questions concerning this matter, please get in touch.with R;: H. Shell at FTS 858-2474.

Very truly yours, i

TENNESSEE VALLEY AUTHORITY

[

L. M. Mills, nager Nuclear Licensing

{

Enclosure cc (Enclosure)*

l Mr.: Richard C. DeYoung, Director Office of Inspection and-Enforcement

'U.S. Nuclear Regulatory Commission Washington, D.C.

20555' y

(RecordsCenter

[

Institute of Nuclear Power Operations -

1100 Circle 75 Parkway, Suite.1500-Atlanta, 0eorgia 30339 Babcock & Wilcox Company r

Attention: LMr.-H. B. Barkley P.0. Box 1260

_'Lynchburg, Virginia 24505

.Y)

1. p16tM gf 84070g65840621#M :

ga fsa;f 1983-TVA 50TH ANNIVERSARY

' An Equal Opportunity Employer 8

ENCLOSURE g

o BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 FAILURE OF MAIN STEAM LINES BECAUSE OF MAIN FEEDWATER OVERFILL NCR BL!! NEB 8004 10 CFR 50.55(e)

THIRTEENTH INTERIM REPORT Description of Deficiency A preliminary safety concern, PSC 35-79, was initiated within B&W, Lynchburg,. Virginia, which presents the concern that a potential exists for overfilling steam generators by excessive addition of main feedwater (MFW) or auxiliary feedwater (AFW).

Excessive feedwater addition, as used here, is defined as a condition which would exist if feedwater (main or auxiliary) is continually added to the steam generators in an unplanned fashion at a rate greater than the core heat generation capability for converting it to steam. Overfill, the conditien addressed in this preliminary safety concern, may be defined as a limiting case of excessive feedwater addition which allows liquid spillage into the steam lines.

It is estimated that the time to overfill the integral econominer once-through steam generators (IEOTSG) provided on the Bellefonte Nuclear Plant is approximately 2 to 4 minutes with MFW and between 7 to 15 minutes with AFW.

Potential results of overfill could be:

1.

Steam line deformation and ~ failure because of water accumulation.

.2.

Steam generator blowdown because of steam line failure with the potential for core return to power from a safe shutdown condition, excessive steam generator tube stress, exceeding reactor vessel NDT limits,' or containment overpressurization.

Interim Progress

~n our previous report, TVA stated that B&W does not believe an AFW l

overfill protection system is required and that this action would not be pursued. However, upon reconsideration, TVA has concluded that this decision warrants further investigation and thus, is still reviewing it.

Therefore, the corrective action for this NCR undertaken by B&W is to provide a design for a safety-grade MFW overfill protection system for the steam generators. B&W has proceeded to provide such a MFW overfill protection system via the BLN upgrade 9Do It Now" (DIN) program item 702. This program is the TVA-instituted program to meet post-Three Mile Island (TMI) upgrade require tents. B&W has submitted to TVA a field change package (FCP) for implementation of DIN 702; however, this FCP has not been approved and is currently undergoing a substantial design change by B&W. The percent completion of this

-corrective action is less than 35 percent.

y

.'f Gr'&W,

L l.

n~u-

,y

P' TVA h;o mvicwed tnd rpproved th3 cnalysis which shows thr.t the min st:amlin] piping cIn withstand tha limited MFW ovsrfill event that is g

postulated to occur with th3 ovcrfill prot:ction system in place. Tha analysis is acceptable, and TVA's Nuclear Engineering Support Branch has received verification and approval of the final analysis by the Civil Engineering Support Branch (CEB). CEB has completed the verification and approval of all six analysis problems associated with this item.~

(Problems N!4-1(2)SM-A, C, K, L, M, and N are all complete.) A copy of the analysis has been sent to B&W for their information and review.

e Outstanding action items associated with this deficiency.are; (a)

TVA's myiew and approval of B&W's FCP for MFW overfill protection system, and (b) completion of TVA's engineering change notice (ECN) related to this change.

I' i

s i

' t ; w e 5,p _

hj&Mi&&&

Jy-

+

s,

.n