ML20097A549

Suppls 901221 Response to Generic Ltr 90-06 Re Stroke Testing of Porvs,Per 920414 Telcon W/Nrc.Routine Testing of PORVs Impractical Under Actual Pressure & Flow Conditions Due to Risk of Losing RCS Inventory & PORV Sticking Open

ML20097A549
Person / Time
Site:	Comanche Peak
Issue date:	05/27/1992
From:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-90-06, GL-90-6, TXX-92255, NUDOCS 9206030022
Download: ML20097A549 (3)

Text

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Log ff TXX-92255

"""T File # 10035 h j 916 (3/4.4.4)

Re f . // GL 90-06 YUELECTRIC May 27, 1992 WUllam J. Cahni, Jr.

Group \' ice Prended U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

t0MANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NOS. 50-445 AND 50-446 SUPPLEMENTAL RESPONSE TO GENERIC LETTER 90-06 REF: TV- Electric letter logged TXX-901053 f rom William J. Cahill, Jr. to USNRC dated December 21, 1990 Gentlemen:

l l The purpose of this letter is to supplement TU Electric's response to Generic Letter 90-06, position 2b, as requested in a telephone conference between the- USNRC and TV-Electric on April 14, 1992.

The guidance in Generic Letter 90-06 provided that stroke testing of Power Operated Relief Valves (PORVs) should be performed in MODE 3 or MODE 4.

TU Electric responded in the referenced correspondence that PORVs would be stroke tested during cold shutdowns as required by ASME Section XI program.

Generic Letter- 90-06 and NUREG 1316 provide little insight as to why MODE 3 L or 4 may- be desired, except to suggest that it would better simulate temperature and pressure environmental conditions. TV Electric recognizes the intent to perform testing und r conditions as close as possible to the '

l _ actual conditions under which' components and systems are expected to perform l their safety function. The impracticality of always doing this is also recognized. For instance, testing.PORVs in MODE 1 is universally recognized

as being impractical. TU Electric also considers routine testing of PORVs i to be impractical under actual pressure and flow conditions because of the risk of losing the RCS inventory and the PORV sticking open. PORV stroking l- is therefore performed with the associated block valve shut.

If the intent is'to have the surrounding environment as near to actual conditions as possible, then'this has little to do with the plant mode at CPSES. The PORVs are influenced primarily by the ambient room conditions which do not show-wide temperature variations in various plant modes and secondarily by the Pressurizer conditions (temperature, pressure). Plant mode is determined by RCS Temperature. The same pressurizer temperature (and therefore pressure) frequently exists in MODES 3. 4, or 5 so there is gnnpr n

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TXX 92255 Page 2 of 2 nn difference from the valve perspective of being in different modes. The PORVs are not closely thermally coupled to the pressurizer because they are separated from the pressurizer by a minimum of 13.6 feet of pipe.

Another consideration f or the CPSES PORVs is that RCS Pressure is applied under the valve seat and tends to assist the valve opening. From this perspective, lower pressure (as with the block valve isolating the PORV) is a more conservative test of the valve and valve operators' ability to open the valve.

It was also suggested that a possible consideration for MODE 3 or 4 testing was to have the PORV stroking performed at a time when it was not required for low Temperature Overpressure Protection (LTOP). This would reduce the out of service time of the PORV and prevent reliance on the Technical Specification Action Statement. CPSES Technical Specification 3.4.8.3 allows either PORVs or RHR Suction Relief Valves to be used for LTOP protection; therefore. CPSES has the ability to test PORVs while satisfying Technical Specifications and LTOP concerns. No reduction in protect ion is necessary and no Action Statement entry is required.

One final consideration related to testing during MODE 3 or 4 is the added scheduling and plant impact. As stated above. there is no technical benefit for the added requirement. TU Electric generally views MODE 3 or 4 as a p transient condition requiring the full attention of the operating staff to transition the plant to either MODE S or MODE 1 as the case may be. Added requirements during this period may not be consistent with the critical path activities needed to transition the plant. This could cause delay or distract attention from higher priority tasks. The more restrictive the .

prerequisite conditions for the test, the more difficult scheduling the -

activity becomes. Absent any obvious benefit of MODES 3 or 4 testing, these negatives make the added requirement not beneficial.

Sincerely, g y ,, ,

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William J. Cahill, Jr.

JLR/tg Attachment c - Mr. R. D. Martin Region IV Resirient inspectors. (2) CFSES Mr. T. A. Bergman. NRR Mr. B. E. Holian, NRR

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At.tachment 1 to TXX-92255 Page 1 of 1 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION in the Matter of )

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Texas Utilities Electric Company ) Docket Hos. 50-445

) and 50-446 (Comanche Peak Steam Electric )

Station, Unit 1 & 2. )

AFFIDAVIT William J. Cahill, Jr. being duly sworn, hereby deposes and says that he is.

Group Vice President, Nuclear of TV Electric, that he is duly authorized to sign and file with the Nuclear Regulatory Commission this response to Generic Letter 90-06: that he is familiar with the content thereof; and that the-matters set forth therein are true and correct to the best of his knowledge, information and belief.

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W i l l i am J Cpi /11, J r . "/ #'

Group Vice PMsident, Nuclear STATE OF TEXAS )

. COUNTY OF hf}'} /L4T-Subscribed and sworn to before me, on this N-t% day of 34 tu / , 1992, 7

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-Notary Public

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