ML20244A803
| ML20244A803 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/09/1975 |
| From: | METROPOLITAN EDISON CO. |
| To: | |
| Shared Package | |
| ML20244A797 | List: |
| References | |
| 75-04, 75-4, NUDOCS 7911150545 | |
| Download: ML20244A803 (2) | |
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Metropolitta Edicen Corp ry
'lhree ::ile Island ? uclear Station, Unit 1 (D 1-1) "
5-1~ X Dac':2t i:o. 50-239 h
Operating License !!o. DP3-50 H;2nroutine 30-Day 2e crt 75-O';
! notification of a Deficiency in Scope of ?calysia Utilized in Deriving Poear vs. Rod 'Jithdrawal Limits 1.
D2nerird: ion of Def t.-iency
!ss a result of discrepancies diceovered by our I:uelear Stee.m Systen Supply (NSSS) vendor when ccaparing predicted ejected rod worth values with actual naasured values for another utility nuclear station (Rancho Seco), further investir;ations vere conducted to verify the adequacy of analyses done in this sere auaject ares. for our Three Mile Island Huelcar Station Unit 1 Paced on these further investigations it hec been dd"*md that:
a.
the Enneho Seco d'ficioney is not re).eted to TMI-l in that 1.
the problen at hncho Seco was due to having used " rod control" type plant rodels for what is c. " soluble boren" controlled plant, and 2.
the correct " rod control" type codels were in fact used for T.MI-l (a "rra control" type plant), but, b.
there doen e:<ist a defi.cianev in. th_e sc.one of enalysi..t.that
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van utilized in deri,ing the Power vs. Rod Withdrawal linits cs contained in the 2:d-l Technical Speci ficatien figurec 3 5-2A, 23, and 2C, in that:
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the anal:.
.::c :ect]y enanced that ejected rod ucrlh:s decrea;ef. - :
bt:~up u ;er tb basinnim of a core tye.1:-
(i. e. F: cr c.0-d sith hurrup, v.; thin each reload cycle),
t fi 2.
ba ned on t'd : t.c:.rption, subjenL Power vs. Rod Withd.nval fj nu e.
Jem 1 by ev - i d"r-: 3 o-Py the bef;innim; of f
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- 2 at:, 3. R-2A, 23, and 2S are not tiequate t o e n.: u re th t.'.
roda nec controlled no as to k e ep e *. e s - 6
U3 rrth I ") le3H than the Speci fi enL3 On
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s 2.' Corrective Actions
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A conprehensiva. analysis of ejacted rod vorths as a function of tire in core life has been conducted, and as a result of this analysis it has been deternined that the present limits of Technical Specification figures 3 5-2A, a.
2B, and 20 have been, and vill continue to be, curricient to ensura. nat er " 3 the Specification 3.5.2.3 rod worth linits up to the time of control rod interchange (note: this is an evolution wherein the assigtr:ent of specific rods to controlling rod group circuits is physically rearranged, so as to alter the order in which indi ridual rods are withdrawn in a nanner which provides for a more uniform fuel burnup; also,- this evolution is currently scheduled for nid-May, 1975),
b.
revised Technical Sp.:ification rigures 3 5-2A, 2B, and 2C vill be inplenented" prior to the first post control rod interchange reactor start-up which vill provide limits sufficient to ensu-e not exceeding the rod vorth limits of specification 3.5 2.3 for the time from control rod interchange to the first refueling, and c.
as may be necesser/ for operations subsequent to the first refueling, additional revisiens vill be made at later dates
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to the subject TA'I-l Technical Specification figures.
3 Preventative Actio n A nanagement review of the circumstances which led to this deficiency is still in progress and, as r.2y be appropriate, edditional preventative actions will be taken.
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It is presently inticipo.ted that this requent for a change to the T:'I-l Tech::ical
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- itted to th;' M Eegulatory Co:.m.icaion by Apri; 11, 3975 I
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