ML20126K402
| ML20126K402 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/18/1985 |
| From: | Weiss E UNION OF CONCERNED SCIENTISTS |
| To: | Asselstine J, Palladino N, Roberts T NRC COMMISSION (OCM) |
| References | |
| CON-#285-602 OLA, NUDOCS 8506110012 | |
| Download: ML20126K402 (2) | |
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"" ' '"" """ ' " " gggM o0 cut mm go UNION OF J
CONCERNED o,cserco j
SCIENTISTS m6 ce....ie., se..e. s.w.. s. noi. we,hi..... oc 20o3e. <2o23 2WE 6
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f April 18, 1985 0FFICE OF SECRETAftY 00CKETthG & SERVIC!.
OE Nunzio J. Palladino, Chairman Thomas H. Roberts, Commissioner James K. Asselstine, Commissioner
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Frederick M. Bernthal, Commissioner Lando W. Zech, Commissioner 4
U. S. Nuclear Regulatory Commission Washington, D. C. 20555 l
Gentlemen:
[.j We were astonished to hear Mr. Clark of GPU Nuclear assert this morning, 4
not once but repeatedly, that the changes to the TMI-1 steam generator tube rupture procedures and safety limits discussed today were not driven by the degraded condition of the tubes.
We are enclosing for your attention the cover sheet sheet and two pages of the GPU Technical Data Report prepared to support the new procedures.
Please note that the section entitled " Introduction and Backg.ound" states as follows:
Since extensive circumferential cracking was discovered in r,
approximately 1200 of the 31,000 tubes, it oecame clear that
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a revised set of procedures for dealing with both single and multiple SGTRs [ steam generator tube ruptures] should be dc. eloped.
TDR 406, Rev. 3, p. 14 ihe following page lists among the activities involved:
Define allowable steam generator stresses during cooldown (either as cooldown rate or as tube /shell delta T).
L Revise minimum allowable subcooling margin.
Waive fuel in compression limits Develop emergency RCP NPSH [ net positive suction head) f
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Jd., p. 15 8506110012 850418 PDR ADOCK 05000289 3
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Stain Office: 26 Church Street. Cambridge. Menachusetts 02238. (617) 547-5552
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j Please also note that Mr. Clark and Mr. Wilson are on the distribution Ei list for this document, which goes on to discuss the need for revising the E}
safety limits in greater detail.
Thank you again for the opportunity to address you today.
Very truly yours,
/
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j Ellyn. Weiss 74 General Counsel 4
Enclosure:
As stated.
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406 REVISION NO. b TDR NO.
g BUOGET 128006 1
81 TECHNICAL DATA REPORT ACTIVITY NO.
PAGE OF
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DEPARTMENT /SECTION REVISION DATE 14 S 93 RELEASE DATE 5 DOCUMENT TITLE:
SC Tube Rupture Procedure Guidelines DATE ORIGINATOR SIGNATURE DATE APPROVAL (S)
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APPROVAL FOR EXTERNAL DISTRIBUTION l DATE go.s.mm Q i.n J
Does this TDRinclude recommendation (s)? Eyes C No if yes. TFWR/TR
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DISTRIBUTION ABSTRACT:
This document provides technical guidelines for dealing R. W. Bensel D. J. Boltz with single and multiple tube ruptures.
A significant T. G. Broughton improvement in procedures will result from reduction of the minimum subcooling margin and RC pump trip on loss M. Campagna P. R. Clark of subcooling margin, valver of fuel-in-compression J. J. Colitz limits, and revised RCP NPSH limits. Other benefits can I. R. Finfrock be derived from revision of the RC pump restart criteria and from additional guidance regarding OTSG steaming and T. L. Gerber R. J. Glaviano isolation.
Finally, revised guidance is provided for R. W. Kesten preventing tube leak propagation.
It is reconenended that the tube-to-shell delta T be limited to 70F0 C. Lehmann during tube rupture events.
D. T. IAighton B. Leonard W. W. Iove d
Revision 2 to this TDR included the following recommendations for procedural revisions, some J. G. Miller of which have already been incorporated in T. Moran EP 1202-5.
M. Nelson j
S. Newton
- 1. Isolate the OTSG's on a measured or projected M. J. Ross dose rate of 50 mrem /hr whole body or 250 mrem /hr H. B. Shipman D. G. Slear thyroid dbse.
C. W. Smyth
P. S. Walsh Dr. R. N. Whitese.*
- 3. Priorities should be spelled out in EP-1202-5:
Minimizing sci has a priority over mini-R. F. Wilson a.
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mizing cooldown time.
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Keeping OISG level belov 95% is less im-portant than control of the RCS cooldown k (f
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Tat 40a Rev. 3
- age 14 of gi L.0 INIR333CIION AND 3ACKCR03bD In November 1931, primary to secondary sida leaks were discovered in the tubes o f bo th o f the IMI-1 Once Through Steam Generators (OISG).
there are 13,531 tubes in each OTSG.
The plant design basis for a steam generator tube rupture (SGTR) accident is the double ended of fse t severence of a single tuba.
S in ce - -
extensive elecumferentLal cracking was discovered in approxlaately L200 of the 31,000 tubes, L e became clear that a revised se t of procedures for dealing wita both single and multtple SGIRs should be developed.
This report describes a program whlen has been formulated to *aprove existing procadures and operator training by providtng improved operator guldelines for dealing vtth tube leakage and tube rupture events.
the guldatines development program vill be described in detail, and the ma jor revis tons to tne exis ting procedures which have been (dentifled as part of the program will bt d is cuss ed.
The proposed guidet tnes will then be presented la caras of their fhe overall s co pe, wL eh a s te p by s te p dis cuss ion o f r equ ire d o pers tor ac t ions.
an alyt L cal ev alua tions wh ich ar e the b as is fo r the r eco mma nda t' on s, cons is t o f a series of staulations whLch are ongoing and will be documentad in datatL in a s ub sequen t r epo r t.
The guidelines in this TDR were tasted a t the &&W simulator training cycle beginning in January,1983.
The results of this cralning experienca are dLscussed. FLnally, the overall conclus ions and major recommendations of the guldelines development progra,a are documentsJ.
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~m TDR 406 Rev. 3 Fage 15 of 81 2.0 TECH'7UNCIIONS SCTR QJ DE! IJES DEWIO RfEN T P.13GRM Figure i shows the executton of the sesam generator tube rupture guideltne development pro gram.
The plan has three main paths: f a ch t is the development of design basis tube rupture guidelines.
Path 2 is the development of multtple tube ruptura guldelines; and, Fa th 3, is a benchmark effort to compare the RETRAN and RELAP 5 computar cod es.
This last ef fort also includes an evaluation of the B&W AIDO analysis of a single tube rupture using MLitfRAP.
The pur pos e o f this TDR is to explain paths 1 & 2.
The benchmarking and comparison efforts are discussed in a separate I)R describ Eng all of the tube rupture analysis work.
None o f the com pu t er analys is o f Pa t h 3 h as The been used to justL fy the recommendatLons of this report.
analyses were an aLd in conceptualtzing the pnysleal processes during a tube rupture.
2.1 Development o f Das ign Bas is Guidelines (Path 1)
The major activittes involved La developing this part of the guldeline were to:
1.
Search existLng industry events and procedures for lessons to be learned about handling tube ruptures.
2.
DefLne allowable stesa generator stresses during cooldown (etther as cooldown rete or as tube / shell delta T)..
3.
Determine when OTSG's should be isolated and when they should be s teamed.
4 Revise the alnimum allowable subcooling margin.
5.
Waive fuel in compression LLat ts.
6.
Develop' energency RCP NPSH lintes.
7 Rede fine entry point condi tions.
8.
Factor Ln experience from use of the guidelines on the &&W slaulator.
Each of these items are ALscussed in de tail in the following sections.
2.1.1 LL tera ture Search Several tube rupture tasks have occurred at various operating reactors within the last four years.
The exper tence gained froa these events has of fered us an opportunity to taprove tube rupture guldelin es.
The mejor lessons learned from these events have been
+ Re v. L
- Rev. I e Rev. 3 2