ML19095A643

LER 1976-002-00 for Surry Unit 1 Inaccurate Thermal Transient Analysis of Worst Break LOCA Core

ML19095A643
Person / Time
Site:	Surry
Issue date:	03/26/1976
From:	Stallings C Virginia Electric & Power Co (VEPCO)
To:	Moseley N NRC/IE, NRC/RGN-II
References
LER 1976-002-00
Download: ML19095A643 (3)

Text

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V~RG:i°NIA 'EL~CTRIC. AND P<,>w~~ c*oMPi~

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. Mr *..~<>rlJ\fl!1.)?,,!_ Moseler<P}i:ec te>r; ,: . ,. <* .i . .* sei::1,.af:Ntj. 9so Office* .of-** Inspect:ion..and* Enforcement . . , * . P()f:M/ ALli: j 1f

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*Region ,II -Suite 818 **.:<-..> . ,. .. Do*~~et No. 50-280 *

. 230 .Peacht:tee Street, Nord1west License.* No. DPR-32 * . :

. Atlanta; Georgia 30303 . . *.

D_ear i:1r ., *Moseley:.

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• . . .. *  :* Put~tiant ,to--*s~rrf*P~i..e~-* Station Techni~al -Specificat;t.on 6*.6~2,. the.

,. '., :.Virginia. El~ctric' and,Pow~r Company: lierehy submits forty (40)-.copies' 'of Re-*

.... p_ortalJ~e*Occurrerice No*. _'AO~s1:..16-*02.' . * * *: * . * .: ... *. . . . . ..

. . .** _.* *** . The* substance of this report has beeu*r~viewE=d. by; the Station Nu ..

• clear, Safety and Operating .Committee* and_ will be**:placed on the. agenda for

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next meeting ' .-

of the.*System

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Nu.¢lea.t--... S1.:1faty.

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_and Operat:i.rig Committee. , I

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Very. trtiif yours, .*.

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. :vice Preiident-Power Supply

. .and.. Production Operations

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.*40._copies Aq..;si-7.6-02 ** *.. I I

cc: .. Mr~ Robert. W. Reid~. Chief . I

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R~a~tors

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AO-Sl-76-02 LINSEE EVENT REPORT

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[PLEASE PRINT ALL REQUIRED INFORMATION]

1 6 LICENSEE LICENSE EVENT NAME LICENSE NUMBER TYPE TYPE

@EJ 7 8 9 lvl Al slP Is 1114I 15 I ol ol-1 olo lo lo lol-1 ol ol 25 1411 26 I 111 lo 30 I Io 31 I 132I REPORT REPORT CATEGORY TYPE. SOURCE DOCKET NUMBER *EVENT DATE REPORT DATE

@E]coNT I MI I I Lu L!J I ol sl ol~lo 12 ls lo I lol311!3!1l6I !0!3!21617!61

7. 8 57 58 59 60 61 68 69 74 75 80 EVENT DESCRIPTION

@:@] I The worst break LOCA core thermal transient analysis is inaccurate in that it does __j 7 8 9 80

@@] ~'--n~o~t_i_n....c""'l'""u....d_e_t_h....e_...;.e_f....f_e_c_t_s_o_f_s_t_e_a"'"m-'-...,g_e_n_e_r...;;;a;...t_o_r_t_u_b_e_...p.._l::;..u"'-'-"g.,_.g'-i-n.._gi,.;..__T_h_i_s_i_*s____r_e..._p_o_r_t_e_d___.p_u;....r_-_ __.l 7 8 9 80

@§ I suant to Technical Specification 6. 6. 2. a. 8 (AO-Sl-76-02) 7 89::;----------------------------'-------'-------~--------8~0 I

1°1 581 9 7 80

[Q:lliJ 7 8 9 PRIME 80 SYSTEM CAUSE COMPONENT COMPONENT CODE CODE COMPONENT CODE SUPPLIER MANUFACTURER VIOLATION 7

@:El 8 9 lz I z I LEJ 10 11 12

!H !TIE Ix I cl HI 17 UIJ43 44 lw l 1 I 2 Io 47 I w48 CAUSE DESCRIPTION

@I@  !steam generator tube deterioration has resulted in the need to plug a number of tubes I 7 8 9 80

-~ lin Surry steam generators.

7 8 9 Surry Unit No. 1 has 5.19% of its steam generator tubes 80 I

[i@] [plugged, and Surry Un{t No. 2 has 3.37% of its tubes plugged. The cause for (cont'd) !

7 8 9 80 FACILITY METHOD OF STATUS  % .POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION EE]

7 8 LzJ 9 10 Io Io Io I 12 13 I NA 44 w45 46 I NA 80 FORM OF ACTIVITY CONTENT rn w RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 7 8 9 W I NA 10 11 44 45 I NA 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION 7

ITellololol 8 9 11 w12 13 NA 80 PERSnNNEL INJURIES NUMBER DESCRIPTION EEja 9l_Q_ ! 0 !

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11 NA 1~2----------------------------------------s-'o OFFSITE CONSEQUENCES lie!8 9l There 7

are no offsite consequences associated with this event.

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LOSS OR DAMAGE TO FACILITY TYPE DESCRIPTION lili1 L?J 10I NA 7 8 9 80 PUBLICITY E1?.l8 7

L i ' I A = - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -80 9

ADDITIONAL FACTORS

~ l__:rhe nuclear steam supply system vendor has recently performed a LOCA analysis to j 7 8 9 80 GEJ Lexamine th_e effects of plugging 6% of the steam generator tubes on each Surry unit. J 7 8 9 80 NAME: E. M. Sweeney, ._J_r_._ _ _ _ _ _ _ _ _ _ _ PHONE: (304) 357-3184_

GPO 8 61

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CAUSE DESCRIPTION (CONT'D)

.e steam generator tube deterioration at Surry has not been isolated. The nuclear steam supply system vendor is conducting exhaustive research into this generic problem with

-PWR steam genera tors.

ADDITIONAL FACTORS (CONT'D)

The major effect of the plugged tubes occurs during the- reflooding phase whereby increasing loop flow resistance results ih decreasing flooding rate.

The approved ECCS Evaluation Model (March 15, 1975 version) was used to perform the analysis using the sequence SATAN/WREFLOOD/LOCTA. The resulting peak clad temperature for 6% plugged tubes was 2142~F using the current technical speci-fication F0 limit of 2.1. These results show that the ECCS criteria, peak clad tem-perature 2200°F, are met for Surry Unit Nos. 1 and 2 with the inclusion of 6%

plugged tubes.

Therefore, the health and safety of the general public was not affected by this occurrence.

Follow up analysis is being conducted by the nuclear steam supply system vendor. This analysis will define the allowable percentage of steam generator tubes that m.~y be plugged in each Surry unit. A supplementary report will be submitted when the results of this analysis are known.