ML19256G052

Forwards Response to NRC 791112 Ltr Re Environ Qualification of Reactor Coolant Temp Detectors & Containment Pressure Transmitters.Calculation Results Encl

ML19256G052
Person / Time
Site:	McGuire, Mcguire
Issue date:	12/19/1979
From:	Parker W DUKE POWER CO.
To:	Baer R Office of Nuclear Reactor Regulation
References
NUDOCS 7912270327
Download: ML19256G052 (4)

Text

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DUKE POWER COMPANY Powra Buturwo 422 SocTn Caracu STnzzT. CitAnt.oTTE, N. C. 2824a wiwau o. an<ca sa.

v.ec p.cs. :c,., December 19, 1979 c.c.-c c: 4 c. -:4 S e c= =

• n':N ev.c = 373-4 S3 Mr. Harold R. Denton, Director Office of Nuclear Reactor Rezulation U.S. Nuclear Regulatory Commission IJashington, DC 20555 Attention: Mr. Robert L. Baer, Chief Light tiater Reactor Branch No. 2 Re: StGuire Nuclear Station I'ni t s 1 and 2 Docket Nos. 50-369, 50-370

Dear r. Denton:

Attached is Duke Pcwer Cerpanc's resconse to the request for information contained r Mr. Robert L. Baer's lettec of 3cvember 12, 1975', concerning environmental qualification of reactor coolant terrerature detectors and containment pressure transmitters.

/

Ve.ty truly youro. /

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h d . t h d% ,'

y%'illiam O. Parker, Jr. '

GAC/sch Attachment p ?'0G Meg, jd

/ \ 1644 008 th Anniversary Ws\Er

1. • owen # 7g

s MC GUIRE NUCLEAR STATION OO Environmental Qualification of RCS Temperature Detectors and Containment Pressure Sensors

1. Provide the results of calculations using the guidelines in this letter (Baer to Parker dated November 16,1979) to detennine acceptable qualified life of resistance temperature detectors to be used to measure reactor ccolant temperature.

Response

Qualification tests concucted by Westinghouse and reported in 'WCAP 9157 used a total radiation dose of 1 x 10 rads. The purpose of this response / calculation is to estimate the in-service life of the RCS wide range and narrow range RTD's working back from the total test dose of 1 x 1Cd rads. The in-service eauipment life is the normal operating life tnat when taken in conjunction with One aDpropriate operatinggtime in the post-LOCA environment yields a total radiation dose of lx10 rads.

The follcaing calculation uses conservative radiation values and assumes tne cost-LCCA RTO ocerating times to ce approximately one hour for the narrcw range RTJ's and 100 d, s fcr the wice range RTD's. This calcu-laticn also evaluatas tne ra nicn e#fects of tne external post-LCCA environment (i .e. , c:ntainment post '.CCA environment) and internal post-LCCA environment (i .e. , post-LJCA environment within the RCS).

External Envircnment The external or ccntainment enviror. ment is the postulated post-LOCA environment seen by the RTD external connection. For the narrow range RTD's, tne post-LOCA dose is on the order of 10 rads because of the RTJ location and required duration of operation (approximately 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />).

Since this accident dose is insignificant when compared to the test conditions, the in-service life for tne narrow range RTD's is calculated as follows assuming a 165R/ hour normal operating dose rate (Ref. 'WCAP 8587, Table 6-2) and an 80% capacity factor:

1.0 x 10 8 = 86 years 7165)(24)(365)(0.8)

Car the wide range RTD's,8WCAP 8587, Figure 6 4, indicates a containment atmospnere dose of 1 x 10 rads for 1:0 days post-LOCA. This value is based on a total integrated dose calculation for a 4100 MW reactor and a containment volume of 1.1 x 10 cubic feet. This Westinghouse calcu-lated dose conservatively sgaled for McGuire yields a post-LOCA 100 day integrated dose of 8.7 x 10 rads. The remaining dose available to cover in-service effects is the difference between the total doge employed in the Westinghouse test reported in WCAP-9157 (i.9. ,1 x 10 rads) and the above calculated post-LOCA dose (i.e., 8.7 x 10 rads), which is 1.3 x 107 rads.

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Page Two-McGuire Nuclear Station ,

U2ing the above information and assuming a 165R/ hour ncrmal operating dose rate (Ref. WCAP 8587, Table 6-2) and an 80% capacity factor, the in-service life of the wide range RTD is calculated as follows:

1.3 x 10 7 = 11.2 years (165)(24)(365)(0.5)

The Westinghouse calculated doses post-LOCA presented in WCAP-8587, Figure 6-4, for the post-LOCA containment environment are conservative with respect to the doses reconi.. ended by the Staff in .NUREG-C588. Fecn Appendjx 0 of this document a conservative 100 day dosg post-LOCA is 2 x 10 Rads for a containment volume of 2.52 x 106 ft and a power of 4000 MW. Repeating the calculation above using this data yields an equivalent in-service life of approximately 50 years for the wide range RID external connections.

Internal Environ: rent The internal environment is the oostulated post-LOCA environment seen by tnat portion of the RTJ located inside the RCS pipir.g. For the narrow range RTD's located in tne bypass line, the r.cident d:se is again : mall

.mn compared to tne test canaitions; therefore, the previous caluclation for the narrow .ange RTD's in-service life is 31:o applicable F.ere and is 36 years.

For the wide-range RTD's, WCAP 8587, Figure 6-8 indicates an RCS internal pipe dose of 1.3 x 10Yrads for 100 days post-LOCA. Witncut :;nsidering any reduction in this value by scaling for F'cGuire, the remaining dose, available to cover in-service radiation effects en the RTD is 8.2 X 10' rads. The cose rate during nonnal operation for wide range RTJ's installed directly in the reactor coolant system is conservatively taken as 320 R/nr as defined for the RCL pipe center in Table 6-2, WCAP-8587.

Using the above information and assuming an 805 capacity factor, tne in-service life of the wide range RTD's is calculated as folicws:

8.2 x 10 7 = 14.3 years (820)(24)(365)(0.8)

Tne assumptions used in cevelopirg Wes-irghcuse internal post-LOCA radiation dose for the wice range RTD's are more realistic than those recomended by the NRC in paragraph C(2) of their letter. It is overly conservative to assume that all of the fission products are contained within the RCS after a LOCA as the NRC recomended.

Sumary Using Westinghouse dose estimates from WCAP-8587 as appgopriate for McGuire, the shortest demonstrated life equivalent to the 1 x 10 rads used in tne RTD tests (WCAP-9157) is defined by the external connections and is conservatively estimated to be 11 years for the wide range RTD and greater than 40 years for the narrow range RTO.

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Page Three-McGuire Nuclear Station

2. Provide the results of tests or analyses to demonstrate acceptable environmental cualification of pressure transmitters to be used to measure containment pressure.

Response

The McGuire design employs the Barton Mcdel 351 pressure sensing bellnws in conjunction with Barton 386A traasmitters for sensing containment p ressure. The Barton 351 sensing bellows are located inside containment and thereforewould be subject to the postulated containment accident environment. The Barton 386A transmitters, however, are located in the annulus and would not be exposed to the harsh containment accident en-vi ronment.

The Barton 351 sensing bellows and the Barton 386A transmitters have been successfully tested as a system in test environments exceeding the postulated accident environments applicaDie to their location. The following table provides a summary of the qualification test data for tne bellows device and the transmitters.

Barton 351 Pressure Sensing Bellows Temperature: 340F (p=ak)

Pressure: 20 psig Radi ati cn : 2 x 100 rads Relati,e Humidity: 1005 (steam)

Barton 386A Pressure Transmitters Temce ra ture : 160F (peak)

Prassure: 20 psig Ra di ation : 2 X 100 rads Relative iiumidity: 100.(steam)

The Barton 351 pressure sensing teilows and tne Sarten 386A transmitters cemonstrated that they could perform their intended function in the simulated environments listed above. The test duration for these devices was 30 days.

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