ML17275A923
| ML17275A923 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 03/16/1981 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Ferguson W WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| References | |
| NUDOCS 8103250379 | |
| Download: ML17275A923 (34) | |
Text
0 ~W QR 16 j981 Docket No.:
50-397 Washington Public Power Supply System ATTN:
Mr. R. L. Ferguson Managing Director 3000 George Washington Way P. 0. Box 968 Rich)and, Washington 99352
Dear Mr. Ferguson:
DISTRIBUTION:
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DEisenhut JYoungblood MDLynch SHanauer MRushbrook RTedesco RVollmer TMurley DRoss RHartfield, MPA OELD OIE,(3)
FEltaw<ila TERA NRC/PDR L/PDR NSIC TIC ACRS (16)
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Subject:
Request for Additional Information Regarding the WNP-2 Facility (CSB)
In the course" of our revieq of your application for an operating license for the Wt]P-2 facility, we have identified a need for additional information.
The information which we need is related to the containment systems and is contained in the enclosure to this letter.
We have also established some positions which we require.you to adopt; these are identified as regulatory staff positions (RSP).
In the enclosure, Items 022.088 through 022.106 are related to your proposed hydrogen recombiner.
If you have any questions on these matters, please contact the Project
- Manager, t1. D. Lynch at 301/492-8413.
Sincerely, RNgfnal af@od 5y
@heist 4 Totlceoo Robert L. Tedesco, Assistant Director for Licensing Division of Licensing
Enclosure:
As stated cc:
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I Mr.
R. L. Ferguson Manag.ing Director Washington Public Power Supplg System P.
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Box 968 3000 George Washington Way Richland, Washington 99352 ccs:
Nicholas Reynolds, Esq.
Debevoise 8 Liberman 1200 Seventeenth
- Street, N.
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Washington, D.
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20036 Richard g. guigley, Esq.
Washington Public Power Supply System P.
0.
Box 968
- Richland, Washington 99352 Nicholas Lewis, Chai rman Energy Facility Site Evaluation Council 820 East Fifth Avenue Olympia, Washington 98504 Mr. 0.
K. Earle Licensing Engineer P.
0.
Box 968
- Richland, Washington 99352 Mr. Albert D. Toth Resident Inspector/HPPSS-2 NPS c/o U.
S. Nuclear Regulatory Commission P.
0.
Box 69 Richland, Washington 99352 C
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021.0 CONTAINMENT SYSTEMS BRANCH 022.064 Provide a list, including appropriate drawings, identifying all piping, equipment, instrumentation and structures in the WNP-2 containment which may be subjected to pool dynamic loads.
In addition, provide drawings showing the location of access galleys in the wetwell, the vent vacuum breaker configuration, the wetwell grating, the vent bracing configuration, the vent configuration in the pedestal region of the wetwell and any large harizontal structures in the zone affected by the pool swell phenomenon.
022.065 Discuss the applicability of the generic supporting programs, tests and analyses (e.g.,
those relating to fluid-structure interactions, downcomer stiffeners and downcomer diameters) to the design of the WNP-2 facility.
022.066 Provide the time history of plant specific loads and your assessment of responses of plant structures, piping, equipment and components to pool dynamic loads.
Identify any significant plant modifications which you made due to considerations of the pool dynamic loads.
I 022.067 Provide the analyses which you performed to determine the post-swell wave load and the seismic slosh load.
Discuss your analytical model and the assumptions you made in performing these analyses.
C 022.068 Provide the type, number and location of the temperature instrumentation which will be installed in the suppression pool for the suppression pool temperature monitoring systems.
Discuss the sampling and/or averaging technique that you will use to arrive at a definitive pool temperature.
Provide justification for your approach.
022-17
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022.069 Based on our review of the information presented in Section (RSP) 6.2.1.1.5 of the FSAR and your response to Item 022.18 which references your response to Item 031.070, we find that your discussion of steam bypass from the drywell to the wetwell for postulated small steam line breaks, is unacceptable.
Specifically, the maximum allowable bypass leakage which you calculate (i.e., A/JK = 0.028 sq. ft.), is not acceptable.
Accordingly, we require that you design the MNP-2 containment to have a bypass leakage capability which satisfies the provisions of Appendix I to Section 6.2.1.1.C of the Standard Review Plan (SRP); (i.e., A/~K = 0.05 sq. ft.).
Provide the appropriate discussions, justifications and analyses to demonstrate how you comply with the provisions of Appendix I cited above.
022.070 You state in your response to Item 022.6 that closed systems are not relied upon as barriers to eliminate bypass leakage.
However, in your response to Item 022.35, you indicate that the reactor feedwater lines are the only lines for which a water seal is assumed to prevent secondary containment bypass leakage.
Accordingly, explain your rationale for eliminating some of the penetrations listed in Table 6.2-16 of the FSAR as potential bypass leakage paths.
022.071 Describe the test which you will perform to verify your assumptions about the amount of inleakage and the drawdown time for reestablishing
-0.25 inches of water gauge in the secondary containment following a postulated loss-of-coolant accident (LOCA).
022. 072 (RSP)
In Table 6.2-16 of the FSAR, you indicate that some lines which are connected to the reactor coolant pressure boundary or which connect 022-:,18
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directly to the containment atmosphere, rely on manual valves for containment isolation following a postulated LOCA.
We find this approach unacceptable.
Accordingly, we require you to provide containment isolation provisions which satisfy the requirements set forth in General Design Criteria (GDC) 55 and 56 of Appendix A to 10 CFR Part 50; these specific GDC require automatic isolation.
022.073 In Table 6.2-16 of the FSAR, you indicate that the reactor'ecircula-tion hydraulic lines (X-76 and X-77) conform to the requirement of Criterion 57 of the GDC. It is our position that the isolation provisions for these specific lines should meet the requirements of Criterion 56.
Further, in Table 6.2-16 of the FSAR, you indicate that the traversing incore probe (TIP) system conforms to the requirements of Criterion 54 of the GDC.
(Refer to Note 29 of Table',"6.2-16.)
However, in Section 6.2.4.3.2.3 of the FSAR, you indicate that the TIP system conforms to the requirements of Criterion 57 of the GDC. It is our position that the TIP system should meet the requirements of GDC 56.
Accordingly, revise Table 6.2-16 and other appropriate portions of the FSAR to reflect our position.
Indicate if the other acceptable alternatives for meeting the requirements of the GDC as noted in Section 6.2.4 of the SRP could be applied to any of these lines.
022.074 In note 31 of Table 6.2-16, you indicate that primary containment and reactor vessel isolation signals are not desirable signals for initiating closure of the feedwater block valve.
We find this approach acceptable provided that the valve can be manually closed from the control room (i.e., remotely) if the control room operator determines that continued makeup from the feedwater system is either unavailable or unnecessary.
Discuss the information which will be available to 022-19
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the control room operator to alert him of the need to isolate the feedwater system.
Indicate the time interval which would elapse before this information became available to the control room operator and indicate the time it would then take the operator to complete this action.
022.075 Provide assurance and/or justification that all valves providing containment isolation and which will be tested in the reverse direction, will be tested on the same basis as those valves for which the manufacturer's data are available to justify testing containment isolation valves in the reverse direction.
Discuss your plans for having this information available for inspection on site by Region V of the office of Inspection and Enforcement.
022.076 With regard to Note 45 of Table 6.2-16 of the FSAR, you should note that our acceptance criteria for containment isolation signals is set forth in Section 6.2.4, "Containment Isolation Systems,"
of the SRP.
Indicate whether your design for the WNP-2 facility conforms to our acceptance criteria on this matter.
022.077 In Section 6.2.5.2.4 of the FSAR, you state that the WNP-2 containment purge system can be used to perform a controlled purge of the contain-ment atmosphere in the event this is necessary to limit the hydrogen concentration in the containment (e.g., following an accident).
We find this approach to be acceptable provided that your purge system is capable of diluting the hydrogen concentration in the cont'ainment atmosphere at the conditions existing in the containment following a postulated LOCA (i.e., the pressure and temperature in the containment at the time hydrogen purging is required).
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022.078 Your response to Item 022.048 cited several references and tests conducted to determine the evolu-,tion of hydrogen following a postulated LOCA.
We are currently undertaking additional effort to better define the various sources of hydrogen, including zinc-rich paints and organic materials.
The following equation which describes the hydrogen generation rates as a function of temperature is currently used by the staff for its confirmatory analysis.
H (SCF/sq. ft. -hr)
= 4.6 x 10 exp (-14500/RT) 5 where:
R (cal/gm K)
= 1.986 absolute temperature (degrees Kelvin)
We are currently reviewing the information presented in your response to question 022.048.
As an acceptable alternative approach to facilitate the staff review, provide a sensitivity study based on the above equation which shows that hydrogen concentration inside the containment will not exceed-our acceptance criterion of 4 volume I
percent.
In responding to this question, indicate the time interval following a postulated LOCA at which the hydro'gen recombiner should be turned on and the amount of time needed to heat up t
the recombiner.
022.079 State the seismic qualification and quality group of the water leg pumps and the associated piping which are used to maintain the water level in the pipes that you identified in your response to Item 022.049, as being filled with water at all times.
022.080 (RSP)
Your response to question 022.050 in which you state that the hydrostatic or pneumatic test will be repeated every ten years, 022-21
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is not acceptable.
It is our. position that those systems identified as closed systems and which become an extension of the primary containment, should be leak tested during each reactor shutdown for refueling, or other convenient intervals, but in no case at intervals greater than two years.
Accordingly, we require you to provide a commitment consistent with our position on this matter.
022.081 In Section 6.2.6.4 of the FSAR, you discuss containment penetrations which employ a continuous leakage monitoring system and indicate they will be Type B tested at every other refueling outage but in no case at intervals greater than three years.
Identify these specific containment penetrations.
022.082 (RSP)
In Note 29 of Table 6.2-16 of the FSAR, you indicate that the TIP system will not be Type C tested as required by Appendix J to 10 CFR Part 50. It is our position the TIP system isolation valve should be Type C tested.
Accordingly, we require you to provide a commitment consistent with our position on this matter.
022.083 The pool dynamic loads resulting from a postulated LOCA which are currently acceptable to the staff are discussed in NUREG-0487, "Mark II Containment Lead Plant Program Load Evaluation and Acceptance Criteria."
Specifically, Table IV-1 of NUREG-0487 summarizes these acceptable Mark II pool dynamic loads.
To expedite our review of the WNP-2 facility, indicate by referring to Table IV-1, which of our generic criteria will be adopted for the WNP-2 facility.
Indicate the alternative criteria that you will use for each item for which an exemption is requested.
Provide references which discuss these alternative criteria.
022-22
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022.084 Provide the input data for your pool swell model, including all initial and boundary conditions.
Demonstrate that the model input represents conservative values of the initial and boundary conditions (i.e., those values which will yield maximum pool swell loads).
In the case of input which is calculated, (i.e., the drywell pressurization and the vent clearing time),
describe and justify your calculational methods.
022.085 Provide in graphic form, the following information:
(a) the pool surface velocity versus position; and (b) the maximum pressures of the suppression pool air slug and the wetwell air space.
022.086 If your pool swell model is significantly different from the pool swell model previously found acceptable by the staff, compare your calculated drywell pressure response and the enthalpy flux in the downcomer vent with the data obtained from the series of tests conducted in the 4T facility using the 2-1/2 inch and 3 inch venturis.
022.087 Provide the information requested in Items 022.084, 022.085, and 022.086, where applicable,,for pool, swell in the pedestal region.
022-23
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022.088 (RSP)
Your performance tests on a scaled down model of the catalyst bed for the WNP-2 hydrogen recombiner, were conducted in a laboratory test facility in which the gas flow rates and size of the catalyst bed are significantly different than those which will be used in the production model.
Indicate the scaling factors used in determining the size of the catalytic bed and the gas flow rates when you established the design of the full-scale recombiner.
Provide justification for these scaling factors, including a
discussion of the catalyst bed volume, the bed depth, the bed area and any experimental verification of the adequacy of these scaling factors., Additionally, we require you to conduct full-I scale tests on a production recombiner unit-including the catalyst, to demonstrate that the hydrogen recombiner will perform its intended function in the containment environment which would occur following a postulated LOCA.
022.089 You conducted catalyst performance tests using a feed gas composition which did not contain steam.
Investigate the effect on the various components of the recombiner system and the overall effect on system performance, of having superheated steam in the feed gas.
022.090 In the event of a small steam line break, the potential exists for steam to bypass the suppression pool via the hydrogen control system.
Discuss the capability of the hydrogen recombiner system to condense this superheated steam.
Discuss whether the after-cooler could be initiated independently from the recombiner system to condense leaking steam.
Discuss the design provisions in the WNP-2 facility to eliminate the potential for steam bypass.
022-24
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022.091 Since the hydrogen recombiner may be required to operate for months following a postulated LOCA, justify the length of time you conducted the performance tests to qualify the production model's capability to perform for extended periods of time.
022.092 The staff guidance in Regulatory Guide 1.7 indicates that equipment
'or measuring and sampling containment atmosphere should be designed to appropriate engineered safety feature criteria;,i.e.,
seismic Category I and guality Group B.
Indicate whether the measuring and sampling equipment in the WNP-2 facility conforms to this guidance.
Indicate whether the hydrogen analyzer is part of the recombiner package and state whether the analyzer catalyst is the same as the recombiner catalyst.
022.093 Provide the results of the testing program for the blower, the preheater, the after-cooler, the water jet eductor and the separator which demonstrate that these components will perform their intended functions in the containment environment which would occur following a postulated LOCA.
In your response, include a table of the test parameters and the range over which these parameters were varied.
Our position is that your test program should consider the effects of the following variables:
(a) irradiation of all components including electrical equipment;
( b) seismic conditions; (c) thermal cycling of the equipment and the catalyst bed; (d) the temperature of the components and the effluent gas; (e) the air flow rate; (f) the inlet hydrogen concentration; (g) the fission products and their potential for leakage; and (h) the steam content.
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022.094 Clearly identify the interfaces between the hydrogen recombiner and the plant design, including a discussion of:
a.
whether the recombiner can be operated from the reactor control room; b.
the instrumentation which will be available to the control room operator to permit the operator to monitor the recombiner per-formance; and c.
any special equipment or power supply needed for the operation of the recombiner.
022.095 You state in your proposal for the hydrogen recombiner that the recombiners will be remotely operated'.
However, you do not discuss the need for gaining access to the combustible gas control equipment area following a postulated, LOCA.
'Discuss the necessity and/or requirements for such access and your proposed criteria for potential t
radiation exposure to operating personnel
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Indicate how you considered these requirements and criteria when you selected suitable locations for the combustible gas control equipment.
022.096 You state on page 14 of your report, APCI-78-6P, that you calculated an average air velocity of about 3 feet/sec.
Provide the analysis, including your assumptions, which you used to calculate that velocity.
You also state that the WNP-2 scrubber will operate in a pressure range of 32 to 14 psia and a temperature range of 100 degree F to 220 degree F.
Discuss the effect on the scrubber efficiency and the amount of water entrainment if the hydrogen concentration inside containment necessitates operating the hydrogen recombiner at pressures and temperatures outside the ranges cited above (refer to Item 021.44).
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022.097 You state on page 68 of your report, APCI-78-6P, that a hydrogen concentration level of 2.5 percent is representative of the hydrogen containment atmosphere.
l<e find that a much higher hydrogen concentration could exist in the containment prior to initiating operation of the recombiner.
Accordingly, discuss the applicability of the test you performed using a hydrogen concentration of 2.5 percent in light of the maximum anticipated hydrogen concentration inside containment.
022.098 In Table A of your report, APCI-78-7P, you present an analysis of a postulated failure of the containment atmosphere control system which shows that operator action is required to isolate the affected system and to initiate the standby system.
Indicate the time interval you assume it would take the operator to complete this actiop and provide justification for this amount of time.
Specify the delay time required for the hydrogen recombiner to reach full efficiency (i.e., that time at which the catalyst bed is preheated to the specified operating temperature).
Discuss the effect of this latter g'elay time on the hydrogen concentration inside containment.
022.099 You state on page 6'f your report, APCI-78-7P, that the recycle flow I
I ratio which you selected is based on the containment pressure to achieve the most'fficient system operation.
Explain how this approach maximizes the system efficiency.
- Revis'e Figure 2.1 of.the cited report to include higher containment pressures up to the contain-ment design pressure (refer to Item 022.44).
In addition, indicate:
(a) the information available to the control room operator to initiate 022-27
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022.100 You state on page 12 ofyour report, APCI-78-7P, that the combustible gas control system will perform its intended function at containment pressures up to 26.5 psig even though the system is designed to operate at 16 psig (i.e., the conditions following a postulated LOCA).
Provide either your analysis or experimental data which substantiates this statement.
Also, discuss the effect on the system performance, of initiating the combustible gas control system immediately following a postulated LOCA.
In your response, consider both an inadvertent start and initiation due to a high hydrogen concentration in containment.
Indicate the type of interlock chosen to preclude inadvertent operation of the combustible gas control system.
Specify the design conditions of the different components of the combustible gas control system and indicate the effect of high pressure (i.e.,
the containment design pressure) on the components of the system.
022.101 In reviewing your report, APCI-73-10, we find that only iodine and methyl iodide were used in the tests conducted to determine the effect of potential poisonous materials on the catalyst.
Other materials were not tested because of similar work done by Southern Nuclear Engineering (SNE) and reported in SNE-100.
With regard to these tests:
a.
Justify why the noble gases and their decay products were not
- tested, since they will come in contact with the catalyst.
022-28
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Justify why solvents, such as potassium hydroxide and sodium peroxide which dissolve platinum compounds, were not tested.
c.
The tests conducted by SNE used a flow velocity which is significantly different than the design flow velocity in the WNP-2 hydrogen recombiner (i.e., the Air Products model).
Justify the applicability of the SNE tests to the Air Products hydrogen recombiner.
d.
In the SNE tests which were of short duration, various materials which poison the catalyst were found to reduce the efficiency of the catalyst by zero to 17 percent.
Discuss the possibility that this performance degradation will increase with time.
e.
It is reported that various poisonous materials have only a slight effect on the efficiency of the catalyst.
Discuss the cumulative effect on the efficiency of the catalyst, of all the poisons tested.
f.
The argument is made in concluding that various poisons will have I
only a slight effect on the efficiency of the catalyst, that tests were conducted usipg poison concentrations well in excess of those predicted in containment after a LOCA.
However, tests conducted with methyl iodide do not support this argument.,
In the methyl iodide tests, the poisoning effect did not change as the concentration was reduced.
Discuss the possibility of this same effect occurring with other poisons, including the poison which caused a
17 percent reduction in catalyst efficiency.
g.
The miscellaneous halide test conducted by SNE showed that the efficiency of the catalyst could be reduced from 50 to 95 percent.
022-29
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Discuss the applicability of these results to the Air Products hydrogen recombiner design.
022.102 Indicate whether all potential catalyst poisons have been tested and justify your response.
Demonstrate that the potential catalyst poisons will not have a detrimental effect on the catalyst.
022.103 The concentrations of iodine and methyl iodide used in the tests reported in APCI-73-10 appear to be quite low when compared to the concentrations expected in containment following a postulated LOCA.
State the assumptions which you used to determine the concentrations you used and provide appropriate references.
In your response, include a discussion of both radioactive and stable isotopes.
022. 104 In your discussion in APCI-73-10 of the effect of particulates on recombiner performance, the only solids you considered were the daughter products of radioactive decay of xenon, krypton, iodine and bromine.
Additionally, you indicate that 25 percent of the iodine and bromine was assumed to be release'd to the containment, in accordance with Regulatory Guides 1.3 and 1.4.
- However, these regulatory guides are to be used in evaluating the radiological consequences following a postulated LOCA; they are not conservative when evaluating the amount of hydrogen released.
Accordingly, analyze the effect of particulates on the performance of the hydrogen recombiner if 100 percent of,the noble gases,'50 percent of the halogens and one percent'of, the solids present in the reactor core are released to the containment, as stated in Regulatory Guide 1.7.
022.105 Provide assurance that the catalyst bed will not deteriorate over the 40-year lifetime of the plant.
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022.106 Provide a description of the dynamic testing procedures used in establishing the, design of the WNP-2 hydrogen recombiner system to withstand vibratory loads arising from seismic events, postulated accidents and other causes (e.g.,
pool dynamic loads).
Describe the methods and procedures you employed to calculate the frequency spectra and amplitudes at the equipment supports of this system.
If your analyses and/or testing procedures do not include evaluation of the equipment in the operating mode, indicate how you will assure that this equipment will function when subjected to the combination of seismic loads, accident loads and other vibratory loads.
Criteria acceptable to the staff for a seismic qualification program is contained in Sections 3.9.2 and 3.10 of the Standard Review Plan.
022-31
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