ML20217N081
| ML20217N081 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 04/06/1998 |
| From: | Polich T NRC (Affiliation Not Assigned) |
| To: | Terry C TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| References | |
| GL-96-06, GL-96-6, TAC-M96797, TAC-M96798, NUDOCS 9804080319 | |
| Download: ML20217N081 (5) | |
Text
i w
+
+ '
Mr. C. Lance Terry April.6,21998
. TU Electric !
Group Vice President, Nuclear -
Attn:- Regulatory Affairs Department -
4
. P. O. Box 1002 Glen Rose, TX 76043
SUBJECT:
. REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE GL 96-06 RESPONSE FOR COMANCHE PEAK, UNIT NOS.1 AND 2 (TAC NOS. M96797 AND M96798).
Dear Mr. Terry:
Gerwric ' Letter (GL) 96-06, " Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions," dated September 30,1996, included a n.
. request for licensees to evaluate cooling water systems that serve containment air coolers to assure that they are not vulnerable to waterhammer and two-phase flow conditions. Texas
(
' Utilities Elet.*ric Company (the licensee) provided its assessment for the Comanche Peak Units in letters datcd Jinuary 27 and November 7,1997. In order to complete our review of the 4
licensee's resolution of the waterhammer and two-phase flow issues, we will require additional information a.2 discussed in the enclosure. We.ask that the licensee provide this information by 1
June 30,1998, in order to support our review schedule for GL 96-06.
Sincerely, ORIGINAL SIGNED BY:
j Timothy J. Polich, Project Manager Project Directorate IV-1 Division of Reactor Projects lil/IV Office of Nuclear Reactor Regulation Docket Nos. 50-445 and 50-446
.y
Enclosure:
Request for Additional information 7;
cc w/enet:' See next page N
DISTRIBUTION
.9 Docket File i OGC PUBLIC GHill(4) 1 ACRS'
.TPolich (2)
TGwynn, RIV PDIV-1 r/f.
\\ {
0
. MGamt,oroni.
CHawes JHannon EAdensam (EGA1)
BWetzel-
'GHubbard JTatum LBMarsh -
Document Name: CP96767.RAI f
(
l PD/PDh OFC-PM/D4 -(, -
PM/PD4 LA/PD4-1
-1 MGarknilvw TPolichM CHawes JHannnon NAME 4 /y.
DATE' Il k /98 t/ t, /98 hl3/98 h [M/98 YESfh0)
COPY im YES/NO YES/NO 3
b Y
- OFFICIAL RECORD COPY -
V g
- g 4080 g geo hh h[hgh] gg.
_P PDR f,a
aug O
t UNITED STATES s
g NUCLEAR REGULATORY COMMIS810N 2
WAsNINGToN, D.C. 20006 4 001
~s..../
April 6, 1998 Mr. C. Lance Tony TU Electric Group Vice President, Nuclear Attn: Regulatory Affairs Department P. O. Box 1002 Glen Rose, TX 76043
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE
. GL 96-06 RESPONSE FOR COMANCHE PEAK, UNIT NOS.1 AND 2 (TAC NOS. M96797 AND M96798)
Dear Mr. Tony:
Generic Letter (GL) 96-06, " Assurance of Equipment Operability and Containment integrity During Design-Basis Accident Conditions," dated September 30,1996, included a request for licensees to evaluate cooling water systems that serve containment air coolers to assure that they are not vulnerable to waterhammer and two-phase flow conditions. Texas Utilities Electric Company (the licensee) provided its assessment for the Comanche Peak Units in letters dated January 27 and November 7,1997. In order to complete our review of the licensee's resolution of the waterhammer and two-phase flow issues, we will require additional information as discussed in the enclosure. We ask that the licensee provide this information by June 30,1998, in order to support our review schedule for GL 96-06.
Sincerely, Timothy J.
olich, Project Manager Project Directorate IV-1 Divisipn of Reactor Projects Ill/IV Office of Nuclear Reacter Regulation Docket Nos. 50-445 a.-d 53 446
Enclosure:
Request for AdditionalInformation cc w/ encl. - See next page
_ _ _-m-
1 Mr. C, Lance Terry TU Electric Company Comanche Peak, Units 1 and 2 cc:
Senior Resident inspector Honorable Dale McPherson U.S. Nuclear Regulatory Commission County Judge P. O. Box 2159 P. O. Box 851 Glen Rose, TX 76403-2159 Glen Rose, TX 76043 Regional Adm!nistrator, Region IV Office of the Govemor U.S. Nuclear Regulatory Commission ATTN: John Howard Director 611 Ryan Plaza Drive, Suite 400 Environmental and Natural Arlington,TX 76011 Resources Policy P. O. Box 12428 Mrs. Juanita Ellis, President Avetin, TX 78711 Citizens Association for Sound Energy 1426 South Polk hthur C. Tate, Director Da!!as, TX 75224 Division of Compliance & Inspection Bureau of Radiation Control Mr. Roger D. Walker Texas Department of Health TU Electric 1100 West 49th Street Regulatory Affairs Manager Austin, TX 78756-3189 P. O. Box 1002 Glen Rose, TX 76043 Jim Calloway Public Utility Commission of Texas Texas Utilities Electric Company Electric industry Analysis clo Bethesda Licensing P. O. Box 13326 3 Metro Center, Suite 810 Austin, TX 78711-3326 Bethesda, MD 20814 George L. Edgar, Esq.
Morgan, Lewis & Bockius 1800 M Street, N.W.
Washington, DC 20036-5869
)
1 :.
- REQUEST FOR ADDITIONAL INFORMATION FOR RESOLUTION OF GL 96-06 ISSUES AT COMANCHE PEAK UNIT NOS,1 AND 2 (TAC NOS M96797 AND M96798)
Generic Letter (GL) 96 06, " Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions," dated September 30,1996, included a request for licensees to evaluate cooling water systems that serve containment air coolers to assure that they are not vulnerable to waterhammer and two phase flow conditions. Texas Utilities Electric Company (the licensee) provided its assessment for the Comanche Peak Units in letters dated January 27 and November 7,1997. The licensee's response indicates that the containment air coolers are not safety-related and are cooled by a non-safety related cooling water system, and that this system is isolated during an event. However, the licensee also acknowledges that in
- certain situations it may be desirable to restore the containment air coolers to service to aid in
. containment heat removal. The licensee believes that if the containment air coolers were a
restored to service during accident recovery and a waterhammer occurred, the resultant hydrodynamic loads would be felt primarily in the cooling coils and dissipated 'n the local piping and fittings, and that any leakage from the non-safety related cooling water system would be detected by a surge tank level alarm. In order for the staff to complete its review, the following additional information is required:
1.
It is important that the isolation valves for the non-safety related cooling water system remain operable such that the ability for the valves to close and provide a leak tight seal is assured should a waterhammer occur. Provide a detailed description of the " worst case" scenario that would cause the greatest challenge to these valves, taking into consideration the complete range of event possibilities, system configurations, and parameters. For example, all waterhammer types and water slug scenarios should be considered, as well as temperatures, pressures, flow rates, load combinations, and potential component failures. The following information should also be included:
a.
If a methodology other than that discussed in NUREG/CR-5220, " Diagnosis of Condensation-induced Waterhammer," was used in evaluating the effects of waterhammer, describe this altemate methodology in detail. Also, explain why this methodology is applicable and gives conservative results for the Comanche Peak Units (typically accomplished through rigorous plant-specific modeling, testing, and analysis),
b.
!dentify any computer codes that were used in the waterhammer analyses and describe the methods used to bench mark the codes for the specific loading conditions involved (see Standard Review Plan Section 3.9.1).
I c.'
Describe and justify all assumptions and input parameters (including those used in any computer codes) such as amp;ifications due to fluid structure interaction, cushioning, speed of sound, force reductionsiand mesh sizes, and explain why ENCLOSURE i
e
2 the values selected give conservative results. Also, provide justification for omitting any effects that may be relevant to the analysis (e.g., fluid structure -
interaction, flow induced vibration, erosion),
d.
Confirm that the analyses included a complete failure modes and effects analysis ~
(FMEA) for all components (including electrical and pneumatic failures) that could affect the severity of the waterhammer and confirm that the FMEA is documented and available for review, or explain why a complete and fully documented FMEA was not performed.
e.
Explain and justify all uses of " engineering judgement."
f.
Determine the uncertainty in the waterhammer analysis, explain how the uncertainty was determined, and how it was accounted for in the analysis to assure conservative results.
g.
. Confirm that the waterhammer loading conditions do not exceed any design specifications or recommended service conditions for the non-safety related cooling water system isolation valves, including those stated by the valve vendor.
h.
Provide a simplified diagram of the system, showing major components, relative elevations, and lengths of piping runs.
2.
Describe assurances that exist that the surge tank level alarm will be functional and reliable following accident conditions, including a description of environmental conditions, qualification and redundancy ofinstrumentation and circuitry, etc.
u l
_