ML19332D658
| ML19332D658 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 11/22/1989 |
| From: | FLORIDA POWER CORP. |
| To: | |
| Shared Package | |
| ML19332D655 | List: |
| References | |
| FOIA-89-392 NUDOCS 8912050088 | |
| Download: ML19332D658 (3) | |
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'H18HINtR$YLINE3REAKSQUTSIDECONTAINMEN
. Input for a Justification of-I Continued Operation
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1), It' if recognised by.the NRC. that pipe ruptures' art rare events 'which eey only occur _ under unanticipated conditions,.such as those which alght be 1
caused 1 by possible
- design, construction,'
or operation er r er11-
. unanticipated-loads or unanticipated corrosive environments',
Ref. Standard Review Plan (SRP)'3.6.2,- Branch Technical Position Mt3 3-1, Rev. 2, June ~- 1987.
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- 2) teneric.: Letter '87-11,
- Relaxation in Arbitrary Intermediate Pipe Rupture Requirements',
attainates the requirements for'Jpostulating Arbitrary
,Intereediate Breaks (A!Is) in High Energy Linee.
Approulastely 501 of all
-High Energy Line' Breaks. (HEL9s) postulated at CR3.<are.Alts.
This percentage will lacrease if a -sore refined pipe ~,analyste modeling' techni'q,ue is employed.
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- 3) The original de' sign basis requirement'to consider jet lapintements fres t.sak: Crack type ~ breaks has been changed in Federal Register, Vol. 53, No.
IS, 1/25/89.
This char.ge -is - reflected in the latest SRPs; which only address.the: environmental conse,quences of. Leak Crack breaks.
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- 4) The vast sajority of - saf ety related components routed through HELO areas p
since original plant construction are electrical raceways (conduits)~and 1
L equipsent.
These components typically have redundant trains routed'in l
other areas of'the-plant to maint alfi sufficient ftet sep arkfl on,' e t c.
p (i.e. Appendix A).
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A study and walkdown of the Main Steam line completed in L
August, 1988, identified targets within the Intermediate -
Building that-have not been.snalyzed for HELB Jet impingement effects.
A review of the final report by FPC identified that numerous high energy line breaks were postulated in areae that contain safety related components.
The majority of these' components are conduit as opposed to active squipmeut.'
FPC Engineering is reviewing the list of affected components to determine which,.if any, of the components are required for safe shutdown under the postulated HELS event. and to provide analytical bases for HELB survivability.
FPC is-also reviewing the environmental. qualification of these components
- based on direct ~1mpingement from a HELS.
A followup report Jwill be provided by 9/13/88 which will address these issues.
in greater' detail.
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i non conservative assumptions.
This is attributed to the criteria being generated. prior to.,the SRPs.
Impell's third party review outlined severa approaches a'Vt91able for reducing the number of postulated breaks in High Energy Lines and ultimately the number of protection devices -required to mitigate postulated HELBs.
Since the number of unprotected safety related components located in HELB areas is not easily defined, the actual extent of the HELB problem could not be determined with any reasonable degree of certainty.
Thi s is dee in part to the number of MAR's, and FCN'S, etc., issued over the years for adding,
- revising, relocating, and removing safety related components.
It was-therefore decided to contract an A/E to perform a field walk down and generate an Engineering Study to properly evaluate the alternatives available to resolve the HELB concerns.
Impe11 Corporation was awarded the contract to perform this work and to provide specific recommendations.
The final issue of-the Impe11 Engineering Study was delivered to FPC in August of 1968.
L' Impell's -recommenc ation, on a plant wide basis, is to revise the established L
HELB criteria to current SRP methodologies for reducing ' the number of postulated pipe breaks and the number of safety related components subject to I
L HELB's.
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An Engineer'ing Problem Report was written by Nuclear Operations. Engineering on ' July 6,1988.
-This EPR was written to acknowledge the potential problen of safety related targets subject to jet impingements in the Intermediate Building as identified in the Impell Engineering Study, and to address the potential HELB problem on a plant w.ide basis.
RECOMENDATION 4
Nuclear Operations Engineering's recommendation, from a technical aspect, is to proceed with-updating the HELB criteria presented in gal R+ port e 1811 to conform with the guidelines of current Standard. Review Plan.
This will I
result 'in a substantial reduction in postulated HEL8's outside containment and, will minimize the number of safety reTated targets subject to jet impingement as well as protection' devices necessary to protect safety related components.
Upon completion of the criteria changes, field walkdowns and engineering evaluations of safety related components subject to HELB ' jet.
- impingements must be performed.
Additional jet
- shields, pipe whip restraints, and/or safety related component relocation may be required to-resolve unacceptable HELB/ target interactions.
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