LD-91-010, Responds to NRC 881223 Request for Addl Info Re CESSAR-DC. Forwards Proposed Revisions to CESSAR-DC
| ML20070G852 | |
| Person / Time | |
|---|---|
| Site: | 05000470 |
| Issue date: | 03/04/1991 |
| From: | Erin Kennedy ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| PROJECT-675A LD-91-010, LD-91-10, NUDOCS 9103120463 | |
| Download: ML20070G852 (10) | |
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'Ju ggg ASEA BROWN BON E Al March 4, 1991 LD-91-010 Project No. 675 U. S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555
Subject:
Response to NRC Requests for Additional Information References (A)
NRC Letter, Reactor System Branch RAIs, G.
S. Vissing (NRC) to A.
E. Scherer (C-E), dated December 23, 1988 (B)
NRC Letter, Chemical Engineering Branch RAIs, G. S. Vissing (NRC) to A.
E. Scherer (C-E), dated December 23, 1988
Dear Sirs:
The reference letters requested additional information for the NRC staff review of the Combustion Engineering Standard Safety Analysis Report - Design Certification (CESSAR-DC).
Enclosure I to this letter provides our responses and Enclosure II provides the corresponding revis3< as to CESSAR-j.
DC.
4 Should you have any questions on the enclosed material, please contact me or Mr. S. E.
Ritterbusca of my staff at (203) 285-5206.
Very truly yours, COMBUSTION ENG,INEERING, INC.
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E. H. Kerinehy Manager Nuclear Systems Licensing EHK:1w
Enclosures:
As Stated cc:
P.
Lang (DOE - Germantown)
T.-Wambach (NRC)
ABB Combustion Engineering Nuclear Power
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4 Enclosure I to LD-91-010 l
RESPONSE TO NRC REQUEST FOR ADDITION.L INFORMATION, 5
i REACTOR SYSTEMS AND CHEMICAL ENGINEERING BRANCHES 1
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Ouestion 281.30 In Table 5.3-5, corrections appear to be needed.
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the line for copper, the reaction should be Cu (n, gamma)Cu" and the half-life should be 12.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.
On the line for cobalt, the reaction should be Co" (n, gamma)Co".
Resoonse 281.30 The_ copper and cobalt reactions given in Table 5.3-5 correctly correspond to the neutron threshold detectors and neutron thermal detectors indicated in that table.
For both cases, cobalt-60 (with a half-life of 5.3 years) is the measured product.
In the case of the neutron threshold detectors with copper, the cobalt-60 is produced-by the (n, alpha) reactirn given in the Table 5.3-5.
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Ouestion 281.31 Section 6.1.2, Organic Materials, page 6.1-5, requires plant specific information which will be evaluated before a SER can be prepared.
The future license applicant should provide the following:
Indicate the total amount of protective coatings and organic materials used inside the containment that do not meet the requirements of ANSI N101.2 (1972) and Regulatory Guide 1.54.
Evaluate the generation rate as a function of time of combustible gases that can be formed from these unqualified organic materials under DBA conditions.
Also, evaluate the amount (volume) of solid debris that can be formed from these unqualified organic materials under DBA conditions that can reach the containment sump.
Provide the technical basis and assumptions used for this ovaluation.
The consequences of solid debris that can potentially be formed from unqualified paints are reviewed in Section 6.2.2 of the SER.
The control of combustible gases that can potentially be generated from the organic materials and from qualified and unqualified paints is reviewed in Section 6.2.5 of the SER.
Response 281.31 Protective coatings used inside containment will be requirud to meet the intent of ANSI N101.2 and Regulatory Guide 1.54.
CESSAR-DC Section 6.1.2.1 will be revised to reflect this commitment.
It is the responsibility of the Combined Operating License applicant to justify any deviations from these requirements and the use of any alternate materials.
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Ouestion 440.3 Section 4.6 of CESSAR 80+,
"Punctional Design of Reactivity Control System", provided information that u
is similar to that presented in the CESSAR for the Standard System 80.
To complete the review of this section, the applicant should:
(a) identify differences that may exist due to the upgrade from the C-E System 80 to System 80+,
(b) provide a failure modes and effects analysis (FMEA) of the control rod drive system (CRDS) for the C-E System 80+.
This analysis should l
establish that all essential elements of the CRDS
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are isolated from nonessential elements, and that all essential elements are provided with protection from common mode failures such as effects of high-and moderate-energy line breaks, (c) the FMEA should also include effects of water, air and electrical failures on the CRDS function.
It should also indicate how the CRDS operation will be affected due to water contamination and air contamination.
Edditionally, any other information that is pertinent to this section should be provided for further review.
Response 440.3 (a)
Differences between System 80+ and System 80 include the following:
The Chemical Volume and Control System (CVCS), in accordance with the EPRI Utility Requirements Document, is not credited with any safe shutdown or accident mitigation function in the safety analysis.
This is reflected in Table 4.6-1.
As stated in Section 3.9.4.4.1.3, the System 80+
Control Element Drive Mechanisms (CEDMs) are the same design as those in operation at the Palo Verde Nuclear Generating Station.
The CEDM control system has the same functional design used in previously designed plants, however, hardware
design changes have been implemented for SysteL 80+.
The CEA sequencing and control solid state digital logic was replaced with programmable logic controllers.
Also, the magnetic jack power supply control solid state logic was replaced with a microprocessor logic controller.
Finally, as stated in CESSAR-DC, Section 7.7.1.1.1, the System 80+ CEDMCS includes pulse counting to infer each CEA position by electronically monitoring the mechanical actions within each CEDM to determine when a CEDM has raised or lowered the CEA.
This differs from previous designs which inferred each CEA position by counting the " raise" and " lower" control pulses sent to each magnetic jack control element drive mechanism (b)
Potential failure modes of the System 80+ CEDM Control System (CEDMCS) have been evaluated to determine which single failures must be assumed in the safety-analysis.
(Note that this is a different approach than that for safety systems where the purpose of the failure modes analysis in to ensure that no single failure can prevent the system from performing its required function.)
For the System 80+ CEDMCS, design requirements ensure that certain failure modes cannot occur as the result of a single failure.
The following design requirements apply:
1.
No single malfunction shall cause any of the following CEA drop conditions:
a.
Simultaneous drop of two (2) CEAs of a four (4) or five (5) CEA subgroup.
b.
Simultaneous drop of three (3) CEAs of a four (4) or five (5) CEA subgroup.
c.
Simultaneous drop of four (4) non-symmetrical CEAs of a five (5) CEA subgroup.
d.
Simultaneous drop of two (2) or more CEAs assigned to different CEA subgroups.
2.
No single malfunction shall cause any single CEA to be withdrawn from the core, or allow the withdrawal of any single CEA except in i
the Manual Individual mode of control with that CEA selected for trimming (position adjustment).
3.
No single malfunction shall cause any single CEA to be inserted into the core, or allow the insertion of any CEA except in the Manual Individual mode of control with that CEA selected for trimming.
4.
No single malfunction shall cause non-demand /non-selected CEA motion as detailed belows t
a.
Simultahebus motion of two (2) or thren (3) CEAs of a four (4) CEA subgroup in any mode of control.
-b.
Simultaneous motion of four (4) non-symmetrical CEAs of any five (5) CEA subgroup in any mode of control.
5.
No single malfunction shall allow any power source not interrupted by a reactor trip to provide power to any CEDM coil of any CBA.
All other credible single failures are considered in the safety analysis.
The resulting single failures are addressed in Chapter 15 (e.g., see Table 15.0-4).
(c)
In evaluating CEDMCS compliance with the above design requirements, the following failures are considered without identifying the cause of failure:
1.
The failure of any electrical component in the actuated or non-actuated mode.
2.
The loss or degradation of any single power supply.
3.
The failure of any logic component in either the logic one or logic zero mode.
4.
The shorting, grounding, or loss of continuity of any conductor.
Question 440.4 The CESSAR System 80+ ECCS design includes two high pressure safety injec'. ion (HPSI) pumps with higher design flows than the three HPSI pumps in the design of such pre-System 80 plants as Waterford 3 and SONGS 2/3.
Discuss the basis for reducing the number of HPSI pumps while increasing their individual flow rates in terms of pump reliability, availability, maintenance and any effects on the results of a plant Probabilistic Risk Assessment (i.e., core melt probability, especially for such events as small break LOCAs which rely on the HPSI pumps for success).
ResDonse 440.4 The CESSAR-DC System 80+ Safety Injection System (SIS) includes four (4) high pressure safety injection (HPSI) pumps, each with the same design flow as each of the two HPSI pumps in System 80 plants such as PVNGS 1, 2,
and 3.
The design bases for the SIS is described in CESSAR-DC Chapter 6, Section 6.3.
The PRA impact of this design is discussed in Appendix B to CESSAR-DC.
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Enclosure II to LD-91-010 PROPOSED REVISIONS TO THE COMBUSTION ENGINEERING STANDARD SAFETY ANALYSIS REPORT -
DESIGN CERTIFICATION l
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CESSAR nai"icarios 1
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i overlay cladding, used in the f abrication of components of the engineered safety features system, is controlled to SFN-20FN.
The delta ferrito content of each lot and/or heat of wcld filler metal used for welding of austenitic stainlons steel code components shall be determined for cach process to be used in production.
Delta ferrito determinations for consumable inserts, j
clectrodes, rod or wire filler metal used with the gas tungsten are welding process, and deposits made with the plasma arc welding process may be determined by either of the alternative methods of magnetic measurement or chemical analysis described in Section III of the ASME Code.
Delta ferrito verification should be made for all other processes by tests using the magnetic measurement method on undiluted wcld deposits described by Section III of the ASME Code.
The average ferrite content shall meet the acceptance limits of SFN to 20FN for wcld rod or filler metal.
For submerged arc welding proccaces, the delta ferrito determination for each wire / flux combination may be made on a-production or simulated (qualification) production wold.
D 6.1.1.1.5 Ferritic Stool Welding
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The recommendations of Regulatory Guide 1.50,
' Control of Preheat Temperature for Wolding of Low-Alloy Steel' and Article D,
Section III of the ASME Ccic are followed.
I Moisture control on low hydrogen materials shall conform to the requirements of the ASME Code and/or AWS D1.1,
' Structural Welding Code'.
6.1.2 ORGANIC MATIRIALS 6.1.2.1 Protective Coatings Many coatings which are in common industrial use may deteriorate in the post-accident environment and contribute substantial quantitics of foreign solids and residue to the containment sump.
Consequently, protective coatings used inside the containment M Miwpmponents-14mi-ted-by-site-andfor--exposed-sur4 ace n m,f are demonstrated to withstand the design basis conditions and meet the intent of ANSI N101.2 (1972),
" Protective Coatings (Paints) for Light Water Nuclear Reactor Containment Facilitics,"
and rocommendations of Regulatory Guide 1.54,
" Quality Assurance Requireme.its for Protective Coatings Applied to Water-Cooled Nuclear Power Plants."
Any particulate debric of appreciable size that does occur will either settle to the bottom of the lloldup Volume Tank or will be trapped by the filter scrocn at the
{N bottom of the in-containment refueling water storage tank (IRWST).
The screen size is smaller than the line piping Amendment I 6.1-5 December 21, 1990 r
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