ML18030A333

Forwards Addl Info Re turbine-generated Missiles,Per NRC Request During 810730 Meeting

ML18030A333
Person / Time
Site:	Susquehanna
Issue date:	08/04/1981
From:	Curtis N PENNSYLVANIA POWER & LIGHT CO.
To:	Schwencer A Office of Nuclear Reactor Regulation
References
PLA-896, NUDOCS 8108070115
Download: ML18030A333 (9)

Text

1t eJr REGULATO 1NFORMATION DISTRIBUTION

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ACCESSION NBR:8108070115.

OOC ~ DATE: 81/08/00 NOTARIZED:

NO FACIL:50 387 Susquehanna Steam Electric Stationi Unit ig Pennsylva 50-388 Susquehanna Steam Electric Station<

Unit 2R Pennsylva AUT'0 ~ N A ME AUTHOR AFFILIATION CURTISEV ~ W ~

Pennsylvania Power 8 Light Co ~

RECIP. VAMK RECIPIENl AFFILIATION SCHHENCKREA ~

Licensing Branch 2

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0500 7

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SUBJECT:

Forwards addi -info re request during 810730.

OISTRIBIJTION CODE:

8001S COPIE TITLE: PSAR/FSAR A4tOTS and Rela NOTES:Send IEK 3 copies FSAR 8

LPDR:2 cyst Send ILE 3 copies FSAR LPDR:2 cyst tur oine-generated missilesiper NRC meeting.

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A/D LICENSNG LIC BR 42 LA INTERNAL: ACCIO EVAL BR26 CHEM EVG BR 11 CORE PKRF BR 10 EHRG PRP DEV 35 EQUIP QUAL BRi'3 GEOSCIKNCES 28 HYD/GKO BR 30 I8,E 06 LIC QUAL BR 32

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04 AUX SYS BR 27 CONT SYS BR 09 EFF TR SYS BR12 EMRG PRP LIC 36 FEMA RKP DIV 39 HUM FACT'NG 40 I8C SYS BR 16 LIC GUID BR 33

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TWO NORTH NINTH STREET, ALLENTOWN, PA. 18101 PHONEr (215) 770 5151 NORMAN W. CURTIS Vice President-Engineedng IL Construction-Nuclear 770-5381 August 4, 1981 Mr. A. Schwencer, Chief Licensing Branch No.

2 U.S. Nuclear Regulatory Commission Washington, D.C.

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(P SUSQUEHANNA STEAM ELECTRIC STATION TURBINE MISSILE OPEN ITEMS ER 100450 FILE 841&2 PLA-896

Dear. Mr. Schwencer:

Attached is the information requested by your Mr. John Schiffgens during our July 30, 1981 meeting on turbine generated missiles. It is our understanding that this information is what you require to close this issue.

In the event that you should have any questions, please call Mr. W. W. Williams at 770-4274.

Very truly yours, Mh3

~'.

W. Curtis Vice President-Engineering 6 Construction~nuclear WWtf/mks Attachment 81OB~~Oli O5OOO387 5 egO804 R

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PENNSYLVANIA POWER 8

LIGHT COMPANY II(

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CRD SYSTEM HYDRAULIC CONTROL UNITS The CRD system hydraulic control units (HCU's) on the north side of the Unit 1

reactor building were considered to be targets for purposes of the probability calculation.

As noted in our response to NRC Question 8121.21, the probability calculation for P2 X P3 assumes that "unacceptable damage" to the HCU's could result from a turbine missile strike which might cause penetration or spallation of a defined area of the reactor building face wall.

In actuality, postulated turbine missile damage to the HCU's would not necessarily lead to unacceptable consequences.

First, as noted above, only the HCU's serving half of. the CRD system are within the missile strike zone.

The only failure mode of the HCU's which could prevent scram is complete crimping (total blockage) of the CRD withdraw lines.

Complete severence of withdraw lines will not affect scram function.

Protection for the CRD insert lines is not required during normal reactor operation, since a reactor pressure of 450 psig or higher can adequately scram the control rods.

Complete crimping of no more than one CRD withdraw line in any nine rod array is acceptable.

A turbine missile (or spallation products) striking the HCU's would be expected to sever some lines; however, crimping is unlikely.

Thus, it is believed that a hypothetical turbine missile would only affect a few, if any, of the control rods, and thus scram function would not'e significantly impaired.

Secondly, even if a significant number of control rods failed to insert, the Standby Liquid Control System will be available as a backup for shutting down the nuclear reactor.

As shown on FSAR figure 1.2-21, the Standby Liquid Control System is located southwest of the containment and thus is completely shielded from turbine missiles.

CABLE TARGETS Essential raceways are identified in the Fire Protection Review Report Revision 1, Appendix A.

The assumptions and conditions of the fire review are sufficiently similar to the turbine review so that the results are applicable.

The fire zones and the essential cable in each zone are:

Elev.

Zone R~ac ewa

~Tar et?

719'&A E1K833 F.-28-4 E-25-4 Yes None 749'-5A ElKK21 E-25-5 E-28-5 No No 779'&A A1P075 A1P105 C1P107 E1P005 E-25-6 E-27-6 No No No No The only essential raceway in the target zone for low trajectory missiles in the reactor building is on the 719'evel - raceway E1K833 which controls Division I ESW pump control circuits.

The other raceways are located outside the low trajectory target area.

This can be verified by inspection of the layout drawings provided earlier and referenced here.

ELECTRICAL PENETRATION There are nine electrical penetrations in the northern half of the primary containment above elevation 719', six of these are nonmafetymelated.

The reamining three safetymelated penetrations are all division II; i.e. no division I penetrations could be damaged by Unit 1 turbine low trajectory missiles.

This agrees with the general plant separations arrangement.

The majority of electrical and mechanical equipment located on the north side of the building is division II.

DIESEL POWER CABLE LAYOUT Each diesel generator output cable leaves its cell below grade level and is separated from the other cables.

The cables are routed underground to the east side of the reactor building where the run is embedded in concrete up to each switchgear room.

These cables are not subject to damage from turbine missiles.

A diagram is provided in figure 1 attached.

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