ML20024H262

Forwards Sampling of RCS While in Defueled Mode of Operation

ML20024H262
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	05/22/1991
From:	Cross J PORTLAND GENERAL ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9105310070
Download: ML20024H262 (4)

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P0ftland Gorioral Electric CortixwTy mas i

James E. Cross Vice President, Nuclear i

r May 22 1991 Trojan Nucicar Plant Docket 50-344 hicense NPF-1 i

U.S. Nuclear Regulatory Commission Attn:

Document Control Desk Washington DC 20555 l

Dear Sirs:

Samplinr,_of the Reactor Coolant System _(RCS)

L Pursuant to ditcussions with the Nuclear Regulatory Conunission staff.

Portland General Electric (PCE) Company has taken the attached position with regard to sampling the RCS while in the defueled modo of operation.

This Position was implemented during the current 1991 refueling outage.

The samples obtained before removing the RCS from service were analyzed and compared with the analysos of the samples obtained before returning the RCS to service and determined that no degradation had occurred.

Please contact me if you have any questions on this position.

Sincerely, Attachtsnt et Mr. John B. Martin Regional Administrator, Region V U.S. Nuclear Regulatory Commission i

Mr. David Stewart-Smith State of Oregon Department of Energy

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Mr. R. C. Barr NRC Resident Inspector Trojan Nt.elear Plant I

121 SW Salmon St. Portland, OR 97204

[ON 9105310070 910522 PDR ADOCK 05000344 503/464-8897

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n Trojan Nuclear Plant Dwcument Control Desk Docket $0-344 May 22, 1991 License NPF-1 Attachment Page 1 of 2 SAMPLING OF TiiE REACTOR COOLANT SYSTEM (RCS)

WHILE IN THE DEFUELED MODE OF OPERATION Dacky,round Trojan Technical Specification (TTS) 3.4.7 requires that the RCS chemistry be maintained within the limits speelfled in Table 3.4-1.

TTS 4.4.7 requires that the RCS chemistry be determined to be within the limits of Table 3.4-1 by analysis of the specified parameters at frequencies upecified in Table 4.4-3.

TTS 3.4.7 and 4.4.1 are applic9ble at "all times" to ensure the RCS is OPERABLE.

Table 3.4-1 identifien limits for dissolved oxygen, chloride, and fluoride concentrationo in the RCS.

Table 4.4-3 specifies minimum sampling frequencica of 3 titues per 7 days with no more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> between samplos for dissolved oxygen, chloride, und fluoride concentrations, except that dicucived oxygen is not required to be sampled if the RCS Tavg is less than or equal to 250 degrees F.

Discussion:

The function of the RCS is to transfer heat generated in the reactor core to the steam generators.

The Reactor Coolant Pumpu (ItCPs) provide the recirculation necessary to provide the specified reactor core thermal-hydraulic perf ormance.

The water in the RCS also acts as a neutron moderator and reflector, and as a solvent for the neutron absorbing boric acid used in the chemical phim control system.

The RCS pressure boundary provides a barrier against leakuge and the release of radioactivity generated within the reactor.

(This information can be f ound in FSAR Section 5.1, RCS Sumnary Description. ) With the reactor shutdown, the ItCS is used in conjunction with the realdual heat removal system (RHRS) to remove decay heat.

When the nuclear fuel is removed from the reactor vessel, the RCS no longer has a design function to remove heat generated in the reactor core, to act no neutron moderator or reflector, or to be used ao solvent for boric acid.

When the RCS is deprensurized, the RCPa are not OPERAllLE and the RCS pressure boundary is not needed to contain radioactivity generated from nucicar fuel.

In summary, with the reactor defueled, the RCS is no longer OPERABLE.

TTS 4.0.3 states that " Surveillance Requirements do not have to be performed on inoperable equipment" Inasmuch as the RCS is inoperable CAZ/624aW(4).0591

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Trojan Nuclear plant Document Control Desk Docket 50-344 May 22, 1991 Licenso NPF-1 Attachment page 1 of 2 when in the defuuled mode of operation, the surveillance requirements of TTS 4.4.7 do not have to be performed (i.e., it is not necessary to samplo the RCS 3 times every 7 days for chloridos and fluorides and the maximum time between samples can exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />). The surveillance requirements for chloridos and fluoridos is to minimize corrosion of the RCS.

With the RCS depressurized and cooled-down, the effects from corrosions due to chlorides and fluoridos are insignificant so the effects from not monitoring these variables every 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> will not load to degradation of the RCS (refer to TTS Bases 3/4.4.7, chemistry),

llowever, prior to returning the RCS to OPERABLE conditions, compliance with TTS 3.4.7 must be obtained.

Samples of the RCS will be obtained and analyzed for chlorides and fluorides prior to removing the RCS from service and prior "to returning the RCS to service.

Comparison of the sample results before removal from service with those obtained before returning the RCS to service will ensure no degradation of the RCS occurred or other significant damaging conditions existed during the period when the RCS was not sampled.

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Conclusions:==

In light _of the above, TTS 3.4.7 and 4.4.7 are not violated when chlorido and fluorido samples are not obtained with the RCS in the defueled modo.

The failure to sample the RCS for chlorides and fluorides is not a TTS violation and is not reportable.

Sampics will be obtained before the RCS-is removed from service and prior to returning the RCS to service.

6248W(5)

i NUCLEAR REGULATORY C0hMISSION CORRESPONDENCE TITLE:

C apling. of the Reactor CoolanL S1 stem (RCS)

LETTER NUMBER:

VPN-112-91 DISTRIBUTION:

Internal W. M. liiggins C. P. Yundt W. R. Robincon G. D. Hicks W. F. Peabody M. B. Lackey J. J. Taylor S. P. Sautter A. R. Ankrum S. A. Bauer R. ). Ward D. M. Boursaw C. R. Cox R. A.1:argel TNP:COV REL F:NRC Chrono, PCE to NRC Ext ermal R. Devan H. F. Moomey A. Bless E. Burton R. Lehigh W. Mazurkiewicz LIS 6 2 48':J( 2 ). 0591

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