ML20023D666
| ML20023D666 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 05/12/1983 |
| From: | Knighton G Office of Nuclear Reactor Regulation |
| To: | Oprea G HOUSTON LIGHTING & POWER CO. |
| Shared Package | |
| ML20023A447 | List: |
| References | |
| NUDOCS 8306020024 | |
| Download: ML20023D666 (5) | |
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MAY 121983 Distribution:
EDocket~ File 1 BSheron, RSB
'NRC"PDR "
Docket Hos.: "50-49ff.
L PDR
'50-499' PRC System NSIC LB#3 Rdg GKnighton Mr. George W. Oprea, Jr.
JLee Executive Vice President HSchierling Houston Lighting & Power Company DEisenhut/RPurple Post Office Box 1700 Attorney, OELD Houston, Texas 77001 ELJordan, IE ACRS (16)
Dear Mr. Oprea:
JMTaylor
Subject:
Request for Additional Information - South Texas Project The Reactor Systems Branch (RSB) has identified an additional question with respect to your proposed deletion of the emergency boration system (EBS). This question had been discussed between our staffs during the past months and we request that you provide the information transmitted in the discussion in the fom of an amendment to the FSAR. The RSB also has identified twelve additional questions that are largely based on the STP unique design features of using 14 foot fuel assemblies and of connecting the ECCS to cnly three of the four loops of the reactor coolant l
system.
All of the above questions are provided in Enclosure 1.
Please note that our RSB questions which were previously issued as the 211 series (Questions 211.1 through 211.86 have been issued) are now identified as the 440 series.
We have also included for your information a copy of the NRC " Safety Evaluation Report on the 1981 Version of the Westinghouse Large Break ECCS Evaluation Model" which is pertinent to some of the questions (Enclosure 2).
We request that you provide your responses in the form of an amendment to the FSAR. We also request that you provide us with your schedule, within 60 days of receipt of this letter, by which you plan to respond to this request.
If you need clarification or have any further questions concerning this request contact the Project Manager, Hans Schierling (301/492-7100).
Sincerely, 0:!ginal sigt.id by.
George W. Kr.i?.100 George W. Knighton, Chief Licensing Branch #3 8306020024 830512 PDR ADOCK 05000498 Division of Licensing h
Enclosures:
As stated omer >
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SOUTH TEXAS Mr. G. W. Oprea, Jr.
William S. Jordan, III Esq.
Harmon & Weiss Executive Vice President Houston Lighting and Power Company 1725 I Street, N. W.
P. O. Box 1700 -
Suite 506 Houston, Texas 77001 Washington, D. C.
20006 Mr. J. H. Goldberg Brian Berwick, Esq.
Vice President - Nuclear Engineering Assistant Attorney General Environmental Protection Division
& Construction P. O. Box 12548 Houston Lighting and Power Company P. O. Box 1700 CapifolStation Houston,' Texas 77001 Austin, Texas 78711 Mr. William M. Hill M
- 0. G. B h Manager, South Texas Project Resident Inspector / South Texas Project Houston Lighting and Power Company c/o U. S. NRC P. 0. Box 910 P. O. Box 1700 r
Houston, Texas 77001 Bay City, Texas 77414 Mr. G. W. Muench Mr. P,ichard C. Balough Mr. R. L. Range Assistant City Attorney Central Power and Light Company City of Austin P. O. Box 2121 P. O. Box 1088 Corpus Christi, Texas - 78403 Austin, Texas 78767
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tir. H. L. Peterson Mr. Lanny Sinkin -
Mr. G. Pokorny Ms. Pat Coy Citizens Concerned About Nuclear Power City of. Austin P. O. Box 1088 5106 Cas~ Or Austin, Texas 78767 San Antonio, Texas 78233 Mr. J. B. Poston Mr. Mark R. Wisenberg tir. A. Von Rosenberg lianager, Nuclear Licenisng City Pu'blic Service Board Houston Lighting and Power Company P. O. Box 1771 P. O. Box 1700 San Antonio, Texas 78296 Houston, Texas -77001 Jack R. Newman, Esq.
Mr. Charles Halligan
- Lowenstein, Newman, Axelrad & Toll Mr. Burton L. Lex 1025 Connecticut Avenue,'N. W.
Bechtel' Corporation Washington, D. C.
20036 P. O. Box 2166 Houston, Texas 77001 Melbcrt Schwarz, Jr., Esq.
Baker & Botts Regional Administrator-Region IV One Shell Plaza U.S. Nuclear Regulatory Commission Houston, Texas 77002 611. Ryan Plaza Drive Suite 1000 Mrs. Peggy Buchorn Arlington, ~ Texas 76011 Executive Director Citizens for Equitable. Utilities, Inc.
Route '1,= Box 1684 Brazoria, Texas 77422 jf
Request for Additional Information Reactor Systems Branch (RSB)
Please note that RSB questions previously identified as the 211. series are now listed as the 440. series.
440.1 In response to our previous question (211.85) regarding deletion of the emergency boration system (EBS) from the STP design, you have indicated that EBS deletion was justifiable, since, in the event of a main steam line break, the DNB design bases are met and the radiation releases are within the limits set forth in 10 CFR Part 100. We have reviewed the system aspects of the revised steam line break analysis in FSAR section 15.1.5.
Based on our review we have detemined that the following additional information is required.
If this information has been included elsewhere in your FSAR, appropriate references in Section 15.1.5 will suffice.
Likewise, if the infomation has been provided in the form of other documentation (e.g.
Westinghouse topical reports), references to such documentation (please be specific) is appropriate.
a.
Clarification of the methodology for calculating reactivity feedback, including the effect of nonuniform core inlet temperatures from the reactor coolant loops; justification of the conservatism in the methodology with regard to the peak power obtained.
b.
Clarification of the methodology used in calculating DNBR and verification that the power distributions used for DNBR calculations reflect the effect of nonuniform core inlet temperatures from the reactor coolant loops.
c.
With respect to ESF actuation functions for an SLB, describe and justify the differences between the protection functions at the STP and the actuation functions in NUREG-0452,
" Standard Technical Specifications for Westinghouse PWR's."
Describe the " excessive cooldown protection" function, which, in accordance with the FSAR, provides safety injection in the event of an SLB.
Identify the actuation set points.
2-440.2' Verify that the reflood heat transfer model utilized for the double ended cold leg guillotine (DECLG) break LOCA analysis is acceptable for the STP 14 foot core.
(Refer to the attached SER on the 1981 version of the Westinghouse large break ECCS model.)
440.3 Verify that the STP large break ECCS model incorporates the revised staff requirements for cladding swelling and rupture models described in NUREG-0630, " Cladding Swelling and Rupture Models for LOCA Analysis," April 1980.
(See also attached SER) 440.4 Clarify what assumptions were used regarding single active failure in the FSAR section 15.6.5 DECLG break analysis.
Provide the results of a DECLG break analysis which assumes no active failures if theso results are different from the values listed in Table 15.6.7.
440.5 Clarify which Westinghouse ECCS evaluation model is utilized for the STP DECLG break analysis, the 1978 model (as stated on page 15.6.17) or the 1975 model (as stated on page 15.6.18).
440.6 Verify that the LOCA analyses utilize the correct upper head fluid temperature.
440.7 The STP ECCS design appears to be unique in that only 3 of the 4 RCS loops are connected to the ECCS.
Discuss whether the STP DECLG break LOCA utilized split downcomer nodalization Provide justification for the nodalization method for the split downcomer in light of the fact that STP has one loop without ECCS and the 1981 model justification did not have such an arrangement.
If STP did not use a split downcomer provide justification.
(Note: See also page 6 of the attached SER) 440.8 Verify that the ECCS components are sized such as to provide adequate core cooling in the event of the design base LOCA with two accumulators, one high head and one low head safety injection (HHSI and LHSI) pump functioning, including meeting the acceptance criteria and requirements of 10 CFR Part 50.46 and Appendix K.
Provide the results of a large LOCA analysis with the above assumptions, if these results are different from the values listed in Table 15.6.7.
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The LHSI and HHSI pump curves in Figures 6.3.6 and 6.3.7 appear to be reversed.
Even assuming this, the curves do not always
~~ correspond with the component data in Table 6.3-1 (e.g. different shutoff head and maximum flow values).
Please clarify these discrepancies.
440.10 The ECCS P& ids indicate that the SI pump return ("miniflow")
lines are partially nonseismic Category I.
Demonstrate the adequacy of this design.
440.11-a.
Clarify what automatic and manual actions are required for ECCS switchover to the recirculation mode.
FSAR page 6.3.-14 indicates that the sump isolation valves are automatically opened and the SI pump miniflow valves are automatically closed when low-low RWST level is reached, but that manual action is required to secure the RWST.
Later you state that " failure of the operator to act will cause no adverse effect since switchover is essentially automatic."
In Table 6.3-7 you state that no manual actions are required for cold leg recirculation initiation, but that the operator is instructed to close the RWST valves.
Your response to question 211.34 indicates that interlocks pre-vent the sump isolation valves from opening until the RWST discharge isolation valve and miniflow line isolation valves in the same train are closed.
b.
If operator action is required during switchover, demonstrate that sufficient time is avaliable for the operator to take the proper action to mitigate the consequences of the accident.
c.
The above interlocks and automatic valve actions should be
_ ' ~ ~ ~ ~ ~ indicated in the ECCS P& ids.
440212 Clarify the statemsht'on page 6.3_-5 regarding RHR heat exchangers:
"During ECCS operation no credit is taken-for core. cooling from
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the RHR HX inasmuch as recirculated water is assumed to' be -
returned to the vessel in a saturated condition...without benefit of subcooling". How is decay heat removal accomplished during long tenn retirculation? Is this as2amption utilized in the LOCA analyses?
440.]3 Demonstrate that the required NPSH is available for the HHSI and LHSI pumps by providing pertinent data and drawings, including the pressure drop due to pump suction piping system losses and the elevational difference between the emergency sump bottom and pump impeller.
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