ML20071F906

LER#78-034/03L-0 on 781026:repeated Tripping of Stack Particulate Process Monitor.Caused by Trip Set in Accordance W/Tech Specs Table 2-1 at 9.6x10-2,rather than More Conservative Release Rates 2x10-3

ML20071F906
Person / Time
Site:	Fort Calhoun
Issue date:	11/25/1978
From:	Kusek L OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20071F903	List: ML20071F902 ML20071F906
References
LER-78-034-03L, LER-78-34-3L, NUDOCS 7812010240
Download: ML20071F906 (2)

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LICENSEE EVENT REPORT CONTROL BLOCK: l l l l l l l (PLEASE PRINT OR TYPE ALL REOutRED INFORMATION) i e@

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7 8 60 61 DOCK ET NUMBE R EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h lo l2l lFollowing repeated tripping of the stack particulate process monitor (RM-061),a revievi

o i3; jof Section 2.9 of the Technical Specifications and the monitor setpoint calculations I

o l4 l l vas conducted. It was deter =ined that RM-061 was set to trip in accordance with Table l 10 I s 1 l 2-1 at 9.6 x 10-2 pci/see rather than the more conservative release rate of 2 x 10-3 l 1 o is i I pCi/see as specified in Tech.~ Spec. 2.9(2)b. No release rates were exceeder" since the i y ,j l more restrictive value of 2 x 10-3 pCi/see was used, and has been used, in deter =ining!

lo,g, iall maximum release rates frc= contain=ent. 80 I

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A4 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS lijollThe maximum release rate of particulates with half-lives greater than eight days l L' ' u Ishculd have been 9.h x 10" pCi/see per Technical Specification 2.9(2)b and the NPC 1

,,,,,; interpretation of October 26, 1978. All applicable procedures were changed accordingly.1 l

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,, ,3, gI ssuance of Facility License Change 78-1 (Appendix I Technical Specificatien submittal)l

,, ,,j l vill alleviate the problem identified by this incident. l 80 l 7 8 9 STAE APOWER OTHER STATUS 015 RY DISCOVERY DESCRIPTION li i5 l 1@ l 0l 0l 0l@l NA l W @l Reviev of Technical Stecification l ACTIVITY CO TENT P, ELE ASED OF RELE ASE AMOUNT OF ACTIVITY LOCATION OF RELEASE I I NA I li is 8t 12 7 9 l @ l10Zl@l NA 11 A4 45 80 PERSONNEL EXPOSURES NUMBER DESCRIPTION l l i l 71 10 10l0l@lTYPE 2l @lNA i f P E RSONN E L INJURIES NUM9ER DESCRIPTION I

3 li t a8l 9101010 l@l 12NA 7 11 80 LOSS OF OR DAMAGE TO FACILITY l TYPE DESCRIPTION NA l

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- Mvrence T. Kuse.: m h02 h26 h011 (

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LER ~8-03h O=aha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000265 Attachment No. 3 Safety Analysis The purpose of the stack particulate process monitor (PR-061) is to monitor the presence of radioactive particulates in the plant stack and to auto-matically terminate a release from the plant in order to maintain the part-iculate release rate within the values specified in Tech. Spec. 2.9(2) a and b. Both the Technical Specifications (Section 2.9(2) e.(i) and note (h) of table 2-1) and plant procedures (Standing Order T-12) require that the stack iodine, particulate and gaseous monitors be operable and capable of performing their design function before a containment purge is initiated.

The trip setpoints for the stack particulate prgcess monitor was determined using a maximum release rate valpe of 9.6 X 10_ pCi/see instead of the Tech.

Spec. 2.9(2)b value of 9.h X 10- pCi/see which was identified by the Com-mission interpretation as being the correct value. In view of the very s=all difference between these two numbers ahd the fact that the more restrictive value of Tech. Spec. 2.9(2)b, namely 2 X 10~#pCi/see, was used in deter =ining all maximum release rates from the containment, no radio- , /

activity was released from the plant in excess of Federal limits. During all releases from the cont _.inment the required monitors were operable and capable of ter=inating the release at their preset setpoints.

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- I.ER i8-03h Omaha Public Power District Fort Calhoun Station Unit No.1 Docket No. 5000285 Attachment No. k Failure Data This is the first incident that has arisen concerning the interpretation of Tech. Spec. 2.9(2) and the subsequent determination of plant stack process monitor setpoints.

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