View source for 05000237/LER-1976-053, Updated LER 76-053/01T-1:on 760803,util Advised by GE That MAPLHGR Limits in Effect No Longer Considered Sufficiently Conservative at Low Core Flow Rates.Problem Thought to Be ECCS Models Used to Determine Rates

{{Adams
| number = ML20083R502
| issue date = 01/03/1977
| title = Updated LER 76-053/01T-1:on 760803,util Advised by GE That MAPLHGR Limits in Effect No Longer Considered Sufficiently Conservative at Low Core Flow Rates.Problem Thought to Be ECCS Models Used to Determine Rates
| author name = Dolter J, Stephenson B
| author affiliation = COMMONWEALTH EDISON CO.
| addressee name = Keppler J
| addressee affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION III)
| docket = 05000237
| license number = 
| contact person = 
| document report number = 77-2, LER-76-053-01T, LER-76-53-1T, NUDOCS 8304040295
| document type = LICENSEE EVENT REPORT (SEE ALSO AO RO), TEXT-SAFETY REPORT
| page count = 4
}}
{{LER
| Title = Updated LER 76-053/01T-1:on 760803,util Advised by GE That MAPLHGR Limits in Effect No Longer Considered Sufficiently Conservative at Low Core Flow Rates.Problem Thought to Be ECCS Models Used to Determine Rates
| Plant = 
| Reporting criterion = 
| Power level = 
| Mode = 
| Docket = 05000237
| LER year = 2076
| LER number = 53
| LER revision = 
| Event date = 
| Report date = 
| ENS = 
| abstract = 
}}

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Update Report I
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x LICENSEE EVENT PgORT                                     Previous Report Date: 8/17/c CONTROL DLUCK:(                 l    l    l  l    l    l                              ULIACE PRINT ALL REQU: RED INFCRMATION) 1                          0 t      E                                    L'ctNSE NtNDER                                       YPE                YPE
{ ll lL lD l Rl Sl 2l 7 U9                                       14 l 0l 0l-l0 l 0 l 0 l 0 l 0l-l 0l 0l l4 l1 l1 l1 ll l l0 l1 l 15                                                   25    PS                    30    31    32 CATEC04f              T7P      5                    COCrET NUMDER                             FVENT CATE                    REPORT CATF 01 CON 7 l l l 7 8             57         68 lTl 59 W60 l 0l 5l 0l-l 0l21317 l 61                                    60 l 0 l 8 l 0 l 317 l6 l 69                       74 l0 75 l1 lo l317 l 7l 00 EVENT DESCRPTION gg l Formal notification was received on 8/3/76 from General Electric company advising                                                                           l 7 09                                                                                                                                                          eo Ql that, in light of low-flow ECCS analyses that had been recently conducted, the                                                                                   1 7 89                                                                                                                                                          90 Q l maximum average planar linear heat generation rate (MAPLUGR) limits then in effect                                                                             l 7 00                                                                                                                                                          60
   @ l could no lonner he considered sufficiently conservative at low core' flow rates.                                                                               l 7 89                                                                                                                                                          00 gl General Electric recommended that the MAPLHGR limits be reduced by 5% for core                                                                              j
            'SS"            '^C SOY                COMPONENT COOE                                     M      C   A           VOLATON ME [Rl Cl @j                            lZ lZ lZ l Zl Zl Zl                 l Zl              lZ l9 l9 l9 l               W 7 00 10                      11          12                          17        43             44                47            40 CAUSE DFSCn!PTION gg l Gcneral Elect ric considered the proble ; to be in the ECCS models used to determinc                                                                        l 7 89                                                                                                                                                         EO O
l the' MAPLHGR l imi t s at low core flow rates: acco rd i ng l y , theECCSanalysiswasreeval-)
7 00                                                                                                                                                          LO
   $l ua t hd . a rni t h e rasults were submitted to t hc_l!RC (ref. O.
7 UU Based on thn results nf                   l F AtiUT y 5fATUS                   % POWER                   OTHER STATUS METHOD OF D;SCOVERY                        DISCOVERY DESCR;PTON (Continued) 8 7 0         9 (t_j 10 10l 9l 7l l 12 13_
NA 44 l    [Dj 45
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46 NA                                    l 80 LEAS            OF F LF SE                AMOUNT OF ACTivrTV                                                LOCATCN OF RELEASE H          Ld                   L7J        l                   na                   l        I                                   nA                             I 7 U         D                       10      11                                       44       45                                                              80 PERSONNEL EXPOSUALS NoVDEH                  fyrF        DESCA''f CN H 10101 of                      LZJ         l                   "A                                                                                               I 7 00                     11         12      13                                                                                                                00 PERSONNEL INJun1FS NUMUER                  DE SC4.PT ON i     10101 01                 I                               nA                                                                                              l 7 09                     11 12                                                                                                                                ag OffGITE CONSEQUENCES 39 l                 NA l
7 UU                                                                                                                   '
80 LOSS OR DAMAGE TO FACILITY TYPE          OC SCthPT ON 8 I zj              l            "^                                                                                                                             I 7 o0              10                                                                                                                                         00 PUDLICITY 8l 7 08 H^
_                                                                            l G304040295 770103                                                                                     c5 ADDITIONAL FACTORS                                DR ADOCK 05000 1     l                         NA l
7 89                                                                                                                                                         gg 8I 7 0D nA 80 i
NAME:           J. M.       Dolter                                                      pyggg; EXT. 443

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                             "'s                          /
EVENT DE9CRIPTl0N (Continued)
            ' flew rates of 85% or less. Operating order no. 25-76 was issued to ensure prompt corrective action in the event MAPLHGR values rose to 95% of the limit during low core flow conditions. This was the first reported occurrence of this nature at Dresden.    (50-237/1976-53)
CAUSE DESCRIPTION (Continued) this reevaluation, Commonwealth Edison has determined (with General Electric's concurrence) that no reduction in MAPLHGR limits is appropriate for either Dresden Unit 2 or 3 at low core flow rates (ref. 4). Conequently- the operating order restricting MAPLHGR values to 95% of the limit at core flow rates of 85% or less has been rescinded.
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ADililllSTRATIVE TROCEDURES                                Q.C.P. 15-52.2
                                            /'';               (APPLi; DIX B)        ( i-                            Revision 0 n/
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)                                                           SUPPLEt!ENT TO DVR DVR !!0.                                                    .E FILE 00Ek
                         -                               STA      UNIT.       YEAR    1:0.
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PART I j TITLE CF EVLliT                                                    OCCURRED
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AllD AUTl!0RIZED FOR DISTRIBUT10!1                    ~/ c ~/ '     ?}. i '4_                   /    Jh2
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corhonwea:th Edison 7f'            Dresden Nuctcar Power Station lj ~,          n n, ll1 h(-      ' .
Morris. ;ttinok 00150 N J'd        Tetephone 815/942-2920 CBS Ltr. #77-2                                     January 3, 1977 Mr. James G. Keppler, Regional Director Directorate of Regulatory Operations - Region 111 U. S. Nuclear Regulatory Commission 799 RooseveIt Road Glen Ellyn, Illinois 60137

==REFERENCES:==
: 1)      NRC Docket Nos. 50-237/249
: 2)      Reportable Occurrence report no. 50-237/1976-53, dated August 17, 1976
: 3)      Letter from A. J. Levine .(G.E.) to Z. R. Rosztocy (NRC)
              -                    dated August 24, 1976
: 4)      Letter from G. A. Abrell to D. L. Ziemann dated November 10, 1976 Enclosed please find an update report to Reportable Occurrence report number 50-237/1976-53            This report is being submitted to your office in accordance with the Dresden Nuclear Power Station Technical Specifications, Section 6.6.B.
m           d' /
                                                      ,jf'f9?his.'.
                                                        ' B.' B. 'S tephenson i.v Station Superintendent Dresden Nuclear Power Station BBS:Jo Enclosure cc:    Director of Inspection & Enforcement Director of Management Information & Program Control File /NRC J'
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