ML19332D382

Submits Addl Info Re Fracture Toughness of Main Steam & Feedwater Sys Matls

ML19332D382
Person / Time
Site:	Comanche Peak
Issue date:	11/27/1989
From:	Beck J TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TXX-89748, NUDOCS 8912010110
Download: ML19332D382 (6)

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Log # TXX-89748 File # 10010

-_ .-- 910.3 r r 1UELECTRIC November 27, 1989 ENa$$,'Nr .

U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NOS. 50-445 AND 50-446 REQUEST FOR ADDITIONAL INFORMATION FRACTURE TOUGHNESS OF THE MAIN STEAM AND FEEDWATER SYSTEM MATERIALS REF: TV Electric Letter from W. J. Cahill, Jr. to the U.S. NRC dated September 8, 1989 (TXX-89657) l Gentlemen:

! Prior to submission of Amendement 77, the CPSES FSAR Section 10.3.6.1 stated that ferritic materials in the Containment Pressure Boundary are impact resistance ~ tested. As previously discussed with NRC staff the Containment Pressure Boundary includes the Feedwater Isolation Valves (FWIV), and does not l include the feedwater Check Valves. Design specification, 2323-MS-20B.1, did l not invoke impact testing requirements on=the supplier of the Unit-1 or Unit 2 i FWIV's. At-the time that the Specification was issued ASME B&PV Code,Section III, Subsection NC-2300, stated that impact testing would be done if

. required.by the design specifications. In lieu of impact testing, TV Electric has performed a fracture mechanics analysis and submitted an FSAR amendment I (referenced above) on this subject. Subsequently, representatives from the L NRC and TV Electric have had several discussions on the testing that should be l performed on the FWIV's as a supplement to the fracture mechanics analysis.

The following describes,the additional testing TV Electric proposes for these valves as well as reasons why volumetric testing should not be performed.

IMPACT TESTING UNIT 2 FWIV (2FW-0083)

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l The' attached table shows the various heat numbers of the true primary components of the FWIV's (i.e., body, bonnet and neck). As can be noted, one Unit 2 FWIV (FW-0083) has the same heat numbers as 11 of the 12 components for the four-Unit 1 FWIV's. All the components with the same heat number were issued under a single CMTR (no separate lot numbers).

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i TXX 89748 i November 27, 1989 Page 2 of 4 ,

l TV Electric will remove from the body, bonnet and neck of FWlV 2FW 0083 s

sufficient material to prepare tbree specimens from each component and perform Charpy V Notch Impact Tests in accordance with ASME B&PV Code,Section II, Specification SA 370. The size of the material sample will be approximately 3"x3"x3/4" which is sufficient for the impact tests. Acceptable  ;

results in accordance with ASME B&PV Code,Section III, Subsection NC 2331, 1974 edition, winter 1974 addenda, will be used to supplement the fracture  ;

mechanics analysis.

The above will provide results representative of 11 out of the 12 major i componen'- on tis Unit 1 FWIV's. The remaining component not being tested is the body of FWIV IFW 0077.

PHYSICAL SAMPLE UNIT 1 FWIV (1FW-0077)

The body of FWlV IFW 0077 will have a small physical sample removed and evaluated / tested by an experienced metallurgist to determine the following:

a. Microstructure to determine if the body has been properly heat  !

treated as follows:

Heat Treatment Normalized '

Temperature (OF) - 1650 Time at Temperature - 25.5 Hours Cooling Rate - Air Cooled

b. Chemical properties to assure SA IN material.

In addition to the above, TV Electric will perform surface hardness tests.

TV Electric will also perform the microstructure and chemical properties tests as described above for the valve body of the FWlV 2FW-0083. The data gathered for the body of IFW-0077 will be compared to the same data obtained from 2FW-0083. If the results are similar, i.e., similar microstructure and chemical properties, then TV Electric can conclude that the acceptability of FWIV IFW- ,

0077 can be deduced from the impact tests on FWIV 2FW-0083. This conclusion would be drawn from a comparison of the available dhta and TV Electric would not perform an impact test on the Unit I valve body of FWIV IFW 0077.

. l TXX-89748  :

November 27, 1989 i Page 3 of 4 j 1

TESTS NOT BEING PERFORMED Volumetric examinations of the valve body-to neck and ' oody-to-pipe welds have already been performed for Unit I and 2 FWIV's, and we will continue with the ISI program for these welds as previously committed. Additional volumetric examination of these FWIVs through radiographic or ultrasonic testing (RT/UT) ,

will not be performed.

The basis for nnt performing these volumetric examinations is as follows:

Radiography:

- ASME B&PV Code provides no RT acceptance criteria for Class 2 forgings Radiographs will not provide meaningful flaw sizing results for any flaws detected, particularly considering the wall thickness involved (see attached Figure-1).

Ultrasonic:

addresses UT

- ASME B&PVofCode, examination Section forgings but is V, Articletowar oriented 23 (SA388)d forgings prior to extensive final machining. In order to provide a geometric 1 configuration conducive to ultrasonic examination, the code suggests that round forgings shall be machined to provide cylindrical surfaces for radial examination and the ends shall be machined perpendicular to the axis of 1.he forging for the axial examination. Internal and external calibration notches would also be required if the forging is not solid.

- The FWIV forgin'js are in the final machined state (i.e., complex geometry) and namerous internal and external calibration notches would be required.

- The attached Figure shows a typical cross section for the FWIVs c.nd .

actual measured dimensions for the wall thickness of the valve body.

The variations in wall thickness and non-parallel orientation of internal / external surfaces would render UT signal interpretation difficult or impossible making flaw sizing impractical at best.

TV Electric Level III examiners do not believe that either RT or UT examination of these FWIV's could provide results that would be meaningful to the resolution of this issue.

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TXX-89748 l November 27, 1989  ;

'Page 4 of 4 l 7

EINAL REPORT

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TU Electric will prepare a final engineering report that includes the above  ;

testing results and the fracture mechanics analysis. TV Electric will provide the appropriate conclusions and recommendations based on this engineering report. The Unit 2 FWlVs will be evaluated at a later date.

TU Electric is proceeding on this basis and the final report on this subject will be available for review at the CPSES site by December 15, 1989, t Sincerely, William J. Cahill, Jr.

By: Ms M- --

pnW. Beck ,

Vice President, Nuclear Engineering MCP/smp Attachments .

c - Mr. R. D. Martin, Region IV ResidentInspectors,CPSES(3) p 9

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• Attachme@t to TXX.89748 l

, Page 1 of 2  ;

f TABLE . 1 )

UNIT 1 VALVES HATERIAL HEAT NUMBERS VALVE BODY BONNET NECK  !

TAG # RIR S/N H/N H/N H/N i

BORG IFW-0071 6690 23993 IQ23 1R51 IP77 4ARNER -

.S-20B.1 IFW-0071 6843 23996 1Q83 1R51 IP77 (ORGED SA 105 IFW-0083 6690 23994 IQ23 1R51 IP77 i ISOLATION VALVES 1FW 0089 6690 23995 1023 1R51 IP77 UNIT 2 VALVES MATEBIAL HEAT NUMBERS -

VALVE BODY BONNET NECK +

TAG # RIR S/N H/N H/N H/N i t

BORG 2FW-0071 11807 51320 IQ23 1R51 2D8  :

WARNER MS 20B.1 2FW-0077 13628 54156 1024 1R51 IP77 FORGED SA 105 2FW-0083 13628 54157 IQ23 1R51 IP77 ISOLATION VALVES 2FW-0089 13628 54158 IQ23 1R51 2011 i 9

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<..V* Attachment to TXX 89748

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