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| number = ML17252A271 | | number = ML17252A271 | ||
| issue date = 04/21/1977 | | issue date = 04/21/1977 | ||
| title = | | title = Transmittal of Reportable Occurrence Report No. 50-249/1977-9 | ||
| author name = Stephenson | | author name = Stephenson B | ||
| author affiliation = Commonwealth Edison Co | | author affiliation = Commonwealth Edison Co | ||
| addressee name = Kappler J | | addressee name = Kappler J | ||
| addressee affiliation = NRC/RGN-III | | addressee affiliation = NRC/RGN-III | ||
| docket = 05000237, 05000249 | | docket = 05000237, 05000249 | ||
Line 14: | Line 14: | ||
| page count = 3 | | page count = 3 | ||
}} | }} | ||
=Text= | =Text= | ||
{{#Wiki_filter:Commonwe4t Edison Dresden Nuclear Power Station R.R. #1 Morris, Illinois* 60450 Telephone 815/942-2920 BBS Ltr. # 334 April 21, Mr. James G. Keppler, Regional Director Directorate of Regulatory Operation -Region JI I U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, 111 inois 60137 Enclosed please find Reportable Occurrence report number 50-249/1977-9. This report is being submitted to your office in accordance with the Dresden Nuclear Power Station Technical Specifications, Section 6.6.B. Stephenson tation Superintendent . Dresden Nuclear Power Station BBS:skm Enclosure cc: Director of Inspection & Enforcement Director of Management Information & Control Fi | {{#Wiki_filter:Commonwe4t Edison Dresden Nuclear Power Station R.R. #1 Morris, Illinois* 60450 Telephone 815/942-2920 BBS Ltr. # 334 April 21, 1~77 Mr. James G. Keppler, Regional Director Directorate of Regulatory Operation - Region JI I U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, 111 inois 60137 Enclosed please find Reportable Occurrence report number 50-249/1977-9. | ||
This report is being submitted to your office in accordance with the Dresden Nuclear Power Station Technical Specifications, Section 6.6.B. | |||
}} | Stephenson tation Superintendent . | ||
Dresden Nuclear Power Station BBS:skm Enclosure cc: Director of Inspection & Enforcement Director of Management Information & P~ogram Control Fi 1e/NRC APR 2 G1977 | |||
L | |||
* l1 \ | |||
LICENSE.E EVENT REPORT | |||
.. *CONTROL BLOCK: l 1 | |||
91 I I I I 6 | |||
* .dASE PRINT ALL REQUIRED INFORMATION) | |||
LICENSEE UC EN SE EVENT NAME LICENSE NUMBER TYPE TYPE | |||
~I I I LI 0 1'-~1 1135 1 14 31 I 01° 1.:... I 0 I 0 I 0 I 0 I 0 1-1° I 0 I .1 4 *1 15 1 11 I 1I 1I I 0 | |||
1 11 7 89 25 26 30 ;31 32 REPORT. REPORT* | |||
CATEGORY TYPE SOURCE DOCKET NUMBER EVENT DATE REPORT DATE | |||
@TI]coN'T I I I L!J L!:J I 01 s 1 o 1~1 o 1 2 1 4 I 9 I I 0 I 4 1 1 I o I 71 7 I I7501 4j 212117 17 I 1 * *0 57 58 59 60 61 68 69 74 80 EVENT DESCRIPTION | |||
[filfil I During control rod withdrawal operations at approximately 44% power, the unit 7 8 9 lo1 3 1 I 013erato.r discovered that Rod Block Monitor (RBM) channels 7 and 8 were automatically 7 89!:-'.---------------------------------~....;._----------__.J* | |||
. 8 1 | |||
11 8 lol 4 1 .!;l__.b_y.;..p_a~s_s_e~d=-a_n_d_i_n_d_i_c_a_te_d__e_d_g_e__,r_o_d_s_e_l_e_c_t_ed___w_h_e_n_i_n_t_e_r_i_o_r_c_o_n_t_r_o_1_ro_d_B_-_s_w_a_s_____~l 11 (q{5j *j!;.._ @.; ;:~;.; ; ~" )'" *~:; ; ;*c" 't-"e. ___~:_J_.__o_t__h__e_r._*.;..i_n....t.e_r_io__r_c_o_n_t_r_o_l_r_o_d_s_w_e_re_t_h_e_n_s_e_l,....e_c_t_e_d_t_.o_c_h.,...e_c_k_t_h_e_f:..,.u_n_c_t.:....*i-'o_n_i_n_g--~1 8 | |||
7 8 9 lo Isl~ ~I__.,..,.o_f.__t_h_,e_R_B_M_.--*_c_o_n_t_r_o_l_ro_d_B.;..-_7_w_a_s_t_h_e_o_n_l_y_o_th_e_r__i n_t_e_r_i_o_r_c_o.;..n_t.._r_o_l_r_od__t h_a.,..t_w__a__s_ _ _ _s_Jl 7 8' 9 PRIME. (continued) 80 | |||
. SYST.EM CAUSE COMPONENT. COMPONENT COOE . . COOE COMPONENT CODE SUPPUER MANUFACTURER VDLATlJN | |||
(§0 I I I B I LlJ I II N I sI Tl R I u I ~ I G I 0 I8 I 0 I ~ | |||
7 8 9 10 11 12 17 43 44 47 48 CAUSE DESCRIPTION (olal I Investigation revealed that a shorted diode in the control rod select circuitry I 7 8 9 . . 80 lolsl 1~*--w_a_s___t_h_e....,....c_a_u_s_e_.~o-f_t_h_e_._s...pu___r_ro_u~s--R_B_M_b_y_p_a_s_~_a_n_d___ e_d_g_e_r_o:..,.d__s_e_1_e_c_t_e__d__i_nd-ic_a_t_io_n_f_o_r____~I 11 11 j ioj j~_b_.~_*t_h__c_o_n_t_r_o_l_r_o_d_s_B_-_7_a_n_d_B_-_s_.__T_h_e_d_e_f_e_c_t_iv_e_d_io_d_e_._w_a_s_r_e_p_l_a_c_e_d_,_a__nd_p_r_o_p_e_r_R_B_M___~l 1 | |||
8 7 8 9 80 FACIUTY METHOD OF . ('continued) | |||
*. STATUS " POWER . OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION EE1 l_Ll I 0 I 4 I 4 I *1.___N_A_ _ _ _-" ~ I See 11 Eve*nt Descr i pt i on 1*1 7 .a. 9 10 . 12 13 44 45 46 ,,. 80 | |||
.FORM OF | |||
.ACTIVITY CONTENT rn RELEASED OF RELEASE AMOUNT . OF ACTIVITY LOCATION OF RELEASE | |||
~ ~ l~_NA-.,,.;-----....J' NA 7 8 9 10 . 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION | |||
[ill] I. o L ol 01 L.fJ .-=---*-N_A._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___;.....;...__~--_J 7 8 9 11 .12 . | |||
: 13. BO PERS.ONNEL *1NJURIES NUMBER OESCRl°PTION | |||
[ill] I 0 I 01 01.';::-*-*__._NA_*---------------~---~--~ | |||
7 a*s 11 12 00 OFFSITE , CONSEQUENCES | |||
.E~L 7 8 9 NA 80 LOSS OR DAMAGE TO FACILITY TYPE . DESCRIPTION 7EID8 9lLl NA 10!::--------------------'--....--....;._--------------......:.--------8~0 PUBLICITY | |||
[fill NA | |||
. 7 8 9 80 ADDITIONAL FACTORS Eifil 7 8 9 | |||
*N 60 7~B.9~.----,.-----------.--.------~~----------------....:...------_..:.....:...__......."--~ ~ ED | |||
.. NA-'\1E~.~._,___J_e_f_f_e_r_y....,.R_._w_o_J_*n_a_r_o_w""'s_k_i- - - - - - - - PHONE: _ _E_x_t_._\..;;;~23);;;;;2;;;.___ | |||
GPO a 111.* a 117 | |||
EVENT DESCRIPTION (continued) found to cause :a oypass of the RBM system. Withdrawal of control rods B-7 and B-8 was suspended and an investigation was initiated. | |||
The safety significance of this event was minimal because the RBM backs up p~ocedural rod selections. Although the Tech Specs require the RBM to be | |||
* operab 1e above 30% power, the Tech Spec bases indicate that the RBM function is not necessary below 70% power. The significance was further mitigated by the core location of B-7 and B~8, since both control rods are located one position i~side the core periphery. This is not a repetitive occurrence. | |||
(50-249/1977-9) | |||
CAUSE DESCRIPTION (continued) operation was verif1ed before further withdrawals of control rods B-7 and B-8 were performed. All other interior control rods have been successfu(ly checked for similar problems. This is the first rep0,r_ted failure of any of these diodes. No further corrective action was deem~d~)warranted. The Rod Block Monitoring system. was supplied by the General Electric Company.}} |
Latest revision as of 09:06, 24 February 2020
ML17252A271 | |
Person / Time | |
---|---|
Site: | Dresden ![]() |
Issue date: | 04/21/1977 |
From: | Stephenson B Commonwealth Edison Co |
To: | Kappler J NRC/RGN-III |
References | |
50-249/1977-9 | |
Download: ML17252A271 (3) | |
Text
Commonwe4t Edison Dresden Nuclear Power Station R.R. #1 Morris, Illinois* 60450 Telephone 815/942-2920 BBS Ltr. # 334 April 21, 1~77 Mr. James G. Keppler, Regional Director Directorate of Regulatory Operation - Region JI I U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, 111 inois 60137 Enclosed please find Reportable Occurrence report number 50-249/1977-9.
This report is being submitted to your office in accordance with the Dresden Nuclear Power Station Technical Specifications, Section 6.6.B.
Stephenson tation Superintendent .
Dresden Nuclear Power Station BBS:skm Enclosure cc: Director of Inspection & Enforcement Director of Management Information & P~ogram Control Fi 1e/NRC APR 2 G1977
L
- l1 \
LICENSE.E EVENT REPORT
.. *CONTROL BLOCK: l 1
91 I I I I 6
- .dASE PRINT ALL REQUIRED INFORMATION)
LICENSEE UC EN SE EVENT NAME LICENSE NUMBER TYPE TYPE
~I I I LI 0 1'-~1 1135 1 14 31 I 01° 1.:... I 0 I 0 I 0 I 0 I 0 1-1° I 0 I .1 4 *1 15 1 11 I 1I 1I I 0
1 11 7 89 25 26 30 ;31 32 REPORT. REPORT*
CATEGORY TYPE SOURCE DOCKET NUMBER EVENT DATE REPORT DATE
@TI]coN'T I I I L!J L!:J I 01 s 1 o 1~1 o 1 2 1 4 I 9 I I 0 I 4 1 1 I o I 71 7 I I7501 4j 212117 17 I 1 * *0 57 58 59 60 61 68 69 74 80 EVENT DESCRIPTION
[filfil I During control rod withdrawal operations at approximately 44% power, the unit 7 8 9 lo1 3 1 I 013erato.r discovered that Rod Block Monitor (RBM) channels 7 and 8 were automatically 7 89!:-'.---------------------------------~....;._----------__.J*
. 8 1
11 8 lol 4 1 .!;l__.b_y.;..p_a~s_s_e~d=-a_n_d_i_n_d_i_c_a_te_d__e_d_g_e__,r_o_d_s_e_l_e_c_t_ed___w_h_e_n_i_n_t_e_r_i_o_r_c_o_n_t_r_o_1_ro_d_B_-_s_w_a_s_____~l 11 (q{5j *j!;.._ @.; ;:~;.; ; ~" )'" *~:; ; ;*c" 't-"e. ___~:_J_.__o_t__h__e_r._*.;..i_n....t.e_r_io__r_c_o_n_t_r_o_l_r_o_d_s_w_e_re_t_h_e_n_s_e_l,....e_c_t_e_d_t_.o_c_h.,...e_c_k_t_h_e_f:..,.u_n_c_t.:....*i-'o_n_i_n_g--~1 8
7 8 9 lo Isl~ ~I__.,..,.o_f.__t_h_,e_R_B_M_.--*_c_o_n_t_r_o_l_ro_d_B.;..-_7_w_a_s_t_h_e_o_n_l_y_o_th_e_r__i n_t_e_r_i_o_r_c_o.;..n_t.._r_o_l_r_od__t h_a.,..t_w__a__s_ _ _ _s_Jl 7 8' 9 PRIME. (continued) 80
. SYST.EM CAUSE COMPONENT. COMPONENT COOE . . COOE COMPONENT CODE SUPPUER MANUFACTURER VDLATlJN
(§0 I I I B I LlJ I II N I sI Tl R I u I ~ I G I 0 I8 I 0 I ~
7 8 9 10 11 12 17 43 44 47 48 CAUSE DESCRIPTION (olal I Investigation revealed that a shorted diode in the control rod select circuitry I 7 8 9 . . 80 lolsl 1~*--w_a_s___t_h_e....,....c_a_u_s_e_.~o-f_t_h_e_._s...pu___r_ro_u~s--R_B_M_b_y_p_a_s_~_a_n_d___ e_d_g_e_r_o:..,.d__s_e_1_e_c_t_e__d__i_nd-ic_a_t_io_n_f_o_r____~I 11 11 j ioj j~_b_.~_*t_h__c_o_n_t_r_o_l_r_o_d_s_B_-_7_a_n_d_B_-_s_.__T_h_e_d_e_f_e_c_t_iv_e_d_io_d_e_._w_a_s_r_e_p_l_a_c_e_d_,_a__nd_p_r_o_p_e_r_R_B_M___~l 1
8 7 8 9 80 FACIUTY METHOD OF . ('continued)
- . STATUS " POWER . OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION EE1 l_Ll I 0 I 4 I 4 I *1.___N_A_ _ _ _-" ~ I See 11 Eve*nt Descr i pt i on 1*1 7 .a. 9 10 . 12 13 44 45 46 ,,. 80
.FORM OF
.ACTIVITY CONTENT rn RELEASED OF RELEASE AMOUNT . OF ACTIVITY LOCATION OF RELEASE
~ ~ l~_NA-.,,.;-----....J' NA 7 8 9 10 . 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION
[ill] I. o L ol 01 L.fJ .-=---*-N_A._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___;.....;...__~--_J 7 8 9 11 .12 .
- 13. BO PERS.ONNEL *1NJURIES NUMBER OESCRl°PTION
[ill] I 0 I 01 01.';::-*-*__._NA_*---------------~---~--~
7 a*s 11 12 00 OFFSITE , CONSEQUENCES
.E~L 7 8 9 NA 80 LOSS OR DAMAGE TO FACILITY TYPE . DESCRIPTION 7EID8 9lLl NA 10!::--------------------'--....--....;._--------------......:.--------8~0 PUBLICITY
[fill NA
. 7 8 9 80 ADDITIONAL FACTORS Eifil 7 8 9
- N 60 7~B.9~.----,.-----------.--.------~~----------------....:...------_..:.....:...__......."--~ ~ ED
.. NA-'\1E~.~._,___J_e_f_f_e_r_y....,.R_._w_o_J_*n_a_r_o_w""'s_k_i- - - - - - - - PHONE: _ _E_x_t_._\..;;;~23);;;;;2;;;.___
GPO a 111.* a 117
EVENT DESCRIPTION (continued) found to cause :a oypass of the RBM system. Withdrawal of control rods B-7 and B-8 was suspended and an investigation was initiated.
The safety significance of this event was minimal because the RBM backs up p~ocedural rod selections. Although the Tech Specs require the RBM to be
- operab 1e above 30% power, the Tech Spec bases indicate that the RBM function is not necessary below 70% power. The significance was further mitigated by the core location of B-7 and B~8, since both control rods are located one position i~side the core periphery. This is not a repetitive occurrence.
(50-249/1977-9)
CAUSE DESCRIPTION (continued) operation was verif1ed before further withdrawals of control rods B-7 and B-8 were performed. All other interior control rods have been successfu(ly checked for similar problems. This is the first rep0,r_ted failure of any of these diodes. No further corrective action was deem~d~)warranted. The Rod Block Monitoring system. was supplied by the General Electric Company.