ML19210A735
| ML19210A735 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/17/1978 |
| From: | Herbein J METROPOLITAN EDISON CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| GQL-0747, GQL-747, NUDOCS 7910310549 | |
| Download: ML19210A735 (4) | |
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REGULATORY INFORr1AT10N DISTRIEU~IION SYSTEM (RIUS)50-2G9 DISTRIDUTION FOR INCOMING t*ATERIAL REC: REID R W ORG: HERBEIN J G DOCDATE- 07/1'/75 METROPOL EDISON DATE RCVO: 07/19/~?
NRC COPIES RECEIVED DOCTYPE: LETTER NOTARIZED: NO LTR 1 ENCL 1 SUEJECT:
ADDITIONAL INFO RE REQUEST NO. 69 TECH SPEC CHANGE, OPERAYING LIC.
NO.
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PLAN T NAf1E. THREE T1ILE ISLAND -- UNIT 1 REVIEWER INITIAL:
XRS DISTRIE.UTOR INITIAL: 4
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- DISTRIBUTION OF THIS MATERIAL I S AS FOLLO WS * ** ** * ** * *-r-+ + w * * *+
OENERAL DISTRIBUTION FOR AFTER ISSUANCE OF OPERATING LICEN2E.
(DISTRIBUTION CODE AOO1)
FOR ACTION:
BR CHIEF ORB #4 EC**W/7 ENCL INTERNAL:
D:EO FILE **tJ/ ENCL NRC PDR**W/ ENCL OELD**LTR ONLY 1
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CORE FERFORMANCE EReW./ ENCL HANAUER**W/ ENCL AD FOR SYS & PROJ**W/ ENCL ENGINEERING ER**W/ ENCL REACTOR SAFETY ER**W/ ENCL PLANT GYGTEMS BR**W/ ENCL EFFLUENT TREAT SYSHW/ ENCL EEB**W/ ENCL J.
MCGOUGH**W/ ENCL EXTERNAL:
LPDR'S HARRISBURG, PAwW/ ENCL TERA **(4/ ENCL NSICwW/ ENCL ACRS CAT B+4W/15 ENCL 1493 233
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METROPOLI FAN EDISON COMPANY POST OFFICE BOX 542 READING, PENNSYLVANI A 19603 TELEPHONE 215 - 929 3601 July 17, 1978 GQL 0747 Director of Nuclear Reactor Regulations Attn: R. 'J. Reid, Chief Operating Reactors Branch No. h U. S. Nuclear Regulatory Commissica
'dashingten, D. C.
20555 Eear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Docket No. 50-269 Operating License No. DPR-50 Technical Specification Change Request No. 69 (Additicnal Informatien)
In response to concerns identified by ycur Mr. G. 3. Zwetzig, with respect to the subject Change Request, attached please find additional infor.ation, provided to Metropolitan Edison Ccepany by Babcock & '411ccx.
Sincerely,
/-
/J. G. Herbein
'.' ice President-Generatien JGH:RJS:dkf 1493 234 Attachment W.1]T'T NY-J g,r
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732020290
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ittachment GQL 0747 BORCN REOUIRDENTS
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Background
Technical Specification 3.2 applies to the operational status of the Makeup and Chemical Addition systems. The purpose of Technical Specification 3.2 is to assure capability for adequate RCS boration from all operating conditions to the cold shutdown condition (200 F).
The present B&W standard practice for preparation of this technical specification is to specify boric acid inventory requirements based on core conditions of TO F, no credit for Xenon, 15 Ak/k suberitical margin, and highest vorth CRA stuck fully withdrawn (all other ORA's fully inserted). The reactor is not allowed to be critical un-less at least two (2) sources of boric acid solution are available and operable:
the two sources are the borated water storage tank (BWST) and a tank (s) con-taining concentrated boric acid solation in the chemical addition system. The latter tank (s) =ay be a boric acid mix tank (s), concentrated boric acid storage tankt s), reclaimed boric acid storage tank (s), or boric acid addition tank (s).
The limiting inventory of the BWST is set by LCCA considerations and is gen-erally en the order of 350,000 gallons at 1800 ppm er 2270 ppm boron. However, the limiting inventory of the concentrated boric acid supply is set by the BCS boren ccncentration requirements for cold shutdown, as defined above. Therefore,
the quantity of boric acid in storage from either of the two independent sources is sufficient to borate the RCS to a 1% Ak/k suberitical margin in the cold ecniicien with no xenon and highest vorth stuck CRA at the most limiting time during ^he fuel cycle. For redded plants the most ltniting boric acid volume requirements occur just before control group 7 is withdrawn to provide excess reactivity for the latter fraction of the fuel cycle.
Ststement of Concern 3%T first noticed the deficiency during November-December 1977, while perfcrming a soluble boron shutdown analysis for ene of their customers.
This cycle was of particular interest since the utility was converting from redded to unroaded (push pull) operation.
A cenparison of Technical Specification 3.2 with the recalculated boric acid volume require =ents revealed the boric acid vclu=e storage listed uns insufficient for the next cycle. Further investigaticns revealed the volume specification vc2 inadequate for h e File Island, Unit 1.
Cause of Deficiency 3
The current specification for soluble boron requirements, i.e., 550 ft at 8700 pp: boron in both the boric acid mixing tank and the reclaimed boric acid stcrage tank, was calculated without considering the highest worth CRA stuck out cf the core. The requirement for the volume of borated water determined
- frca calculations assuming 15 shutdevn margin at cold shutdown, the verst time in ccre life, highesj vorth control rod assembly fully withdrawn and no credit for xencn, is 776 ft at 8700 pp= boron in each of the aforementioned tanks.
1493 235
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8 e Safelv Evaluation While the numbers provided in the revised technical specifications have in-creased, there essentially was no degradation in plan + safety for the following reasons:
1.
The BWST vater volume required for the LOCA is.. ell in excess of that required to bring a plant to a cold shutdown. Thus an adequa+e source of borated water existed at all times.
2.
Plant operators are provided with a boron curve vs lifetime for each re-load cycle which includes 15 Ak/k suberitical margin at 70 F with hi hest 6
worth stuck rod and no credit for xenon. During any shutdown the operator uses this curve to insure that the reactor coolant systea contains sufficient boron while in the 0011 shutdown conditions.
3 During normal operatiens the concentrated boric seid storage tank level is kept above the technical specification limit.
L.
The volumes and concen: rations provided by B&W are conservative in that they are calculated for 70 F rather than the 200 F allowed by the specifi-cation to help account for minor variations from cycle to cycle.
In addition, an additional 10% conservatism is applied to the volume requirement.
Also EL*4 applies an additional 10% uncertainty on the control rod worths used in the calculations.
Cortretive Action Revised technical specifications which account for the increased boron requirements were submitted January 27, 1978. These volumes and concen-tration limits have been implemented, as indicated in LER 77-29/lT, December 30, 1977 1493 236
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