ML19341C597
| ML19341C597 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 02/23/1981 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-3.D.3.4, TASK-TM TAC-46471, TAC-46472, NUDOCS 8103030814 | |
| Download: ML19341C597 (16) | |
Text
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1 Wisconsin Elecinc vaara cournur 231 W. MICHIGAN. P.0 BOX 2046, MILWAUKEE. WI 53231 February 23 1981 Mr.
H.
R.
Denton, Director g
A Office of Nuclear Reactor Regulation U.
S.
NUCLEAR REGULATORY COPJ1ISSION H
g Wathington, D.
C.
20555 Malt 0 21981 m Dear Mr. Denton-DOCKET NOS. 50-266 AND 50-301 D f i"^'* ",**
ADDITIONAL RESPONSE TO NUREG-0737 k 4
POINT BEACH NUCLEAR PLANT, UNITS 1 AND
(/
Our December 23, 1980 letter provided our response to the requirements of NUREG-0737, entitled " Clarification of TMI Action Plan Requirements", as pertains to Wisconsin Electric Power Company's Point Beach Nuclear Plant, Units 1 and 2.
Additional information was provided with our letter of January 9, 1981.
Both of our submittals committed to providing additional information on control room habitability.
Attauned is the report of our control room habitability evaluation as required by Item III.D.3.4 of NUREG-0737.
Please advise us if you have any further questions regarding this submittal.
Very truly yours, C. W.
Fay, Director Nuclear Power Department Attachment Copy to: NRC Resident Inspector Subscribed and sworn to before me This 23rd day of February, 1981.
La...-
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Notary Public, State ot Wisconsin My Commission expires
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e ADDITIONtL RESPONSES TO NUREG-0737 POST-TMI REQUIREMENTS FOR OPERATING PLANTS t
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POINT BEACH NUCLEAR PLANT, UNI'"S 1 AND 2 DOCKET NOS. 50-266 AND 50-301 l
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III.D.3.4 CONTROL ROOM HABITABILITY f
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a III.D.3.4 CONTROL ROOM HABITABILITY In accordance with the requirements set forth ir. NtiREG-0737, an evaluation of control room habitability has been performed for Point Beach Nuclear Plant (PBNP).
I.
MODE OF OPERATION To clarify terminology, the folloVing modes of operation are identified in Section 6.4 of the Standard Review Plan:
(1)
Zone isolation with filtered incoming air and positive pressure; (2)
Zone isolation with filtered recirculated air; (3)
Zone isolation with filtered recirculated air and positive pressure; (4)
Dual air inlets; and (5)
Portable air supply for a limite( time.
The HVAC system for the control room at PBNP is shown in t
Figure 1.
Mode I - Normal Operation In the normal operation mode, either supply fan W13B1 or W13B2 operates to provide 19,800 cfm of air to the control room and computer room.
About 25% of outside air is drawn in through dampar CV-4849C.
Mode II - 100% Recirculation through HEPA Filters In the event of a LOCA, increased pressure in the contain-ment aulcmatically isolates the control room, and no outside air is drawn in.
Damper CV-4849A is also closed so that the entire 19,800 cfm air supply is delivered to only the control room.
For this mode, recirculation is only through a HEPA filter.
Mode III - Recirculation through Charcoal Filters This mode is equivalent to Standard Review Plan Type 2, i.e.,
zone isolation with filtered recirculated air.
While W13B continues to run, about 25% (4,950 cfm) is diverted through the emergency charcoal filters by fan W14A or W14B.
Mode IV - Makeup throuch Charcoal Filters i
A further signal from the control room opens the outside l
air damper (CV-4851A) and closes the emergency filter air i
t -
1
damper (CV-4851B).
In this mode, 4,950 cfm of outside air is drawn through the charcoal filters by fan W14A or W14B and provides positive pressurization of the control room.
This mode is equivalent to Standard Review Plan Type 1, i.e.,
zone isolation with filtered incoming air and positive pressure.
The control room has been checked for pressurization in Mode IV.
The results indicated a pressure differential of 0.080" water gauge.
At the present time, ongoing work related to fire protection upgrading precludes the closure of certain leakage areas.
Upon completion of this work, these leakage areas will be sealed in an effort to achieve a differential of 0.125" water gauge in Mode IV.
II.
INFORMATION REQUIRED FOR CONTROL ROOM HABITABILITY EVALUATION 1.
Mode of Operation The available modes of operation in the control room filtration system at PBNP are described in Section I.
As described therein, Modes III and IV are applicable
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to accident evaluation.
Mode IV is the most appropriate mode of operation for severe radiological conditions.
2.
Control Room Characteristics (a)
Control room air volume is 55,195 cu. ft.
(b)
Control room emergency :one includes the control room, the snack bar, and the. toilet.
It does not include the computer room and the engineering offices which are located in the control building.
The latter two facilities are isolated during emergency modes of operation.
(c)
For Mode IV, infiltration leakage rates of both 0 and 10 cfm were used in the radiological evaluation.
A value of 10 cfm is recommended by Section 6.4 of the Standard Review Plan; this is overly conservative to account for opening and closing of doors.
For Mode III, an infiltration rate of 3,312 cfm was assumed in accordance with the recommendation of Section 6.4 of the Standard Review Plan which specifies that 0.06 of the control room volume be used as an infiltration rate in the absence of testing.
(d) 100% HEPA filter efficiency is assumed for i
particulate, non-iodine radioisotopes.
A l
charcoal adsorber efficiency of 99% is assumed i
for elemental iodine.
Charcoal adsorber efficiencies of both 90 and 95% were examined in the evaluation for methyl iodine. -
(e)
The closest
_ stance between the control room air intake and ne containment structure is 124 ft.
(f)
General relationships of the control room and the containments are shown in Figure 2.
(g)
The control room shielding consists of 18" of concrete except for doors lccated on the north and south walls at the eastern-most extent of these walls.
The extent of radiation streaming through these doors is shown in the shaded corner areas in Figure 1.
(h)
Since dual intakes are not used at PBNP, damper closing times and leakages are not required for the analysis.
(i)
Chlorine or toxic gas detectors are not required at PBNP.
(j)
There are two kits of self-contained breathing apparatus (SCBA) and two Biopak-60 units in the control room.
Elsewhere on the site, there are 18 other Biopak-60 units and 5 more SCBA units.
(k)
There are no spare bottles of air in the control rocm, but the capability exists on-site to refill 100 Biopak-60 bottles.
In addition, there are 14 extra bottles for the SCBAs available on-site.
The control rocm is also equipped with provisions for supplied air.
There are three outlets on each side of the control rocm and six full-face masks available.
Although the service air compressors are stripped on safety injection signal, they can be manually restored if loading permits.
(1)
No food is kept in the control room.
Approximately 30 to 60 T.V. dinners are maintained on hand in the cafeteria.
The potable water available in the control room is supplied from the on-site well.
(m)
Emergency equipment has been provided in the control room assuming a complement of six people, including one operation supervisor, one shift supervisor, two reactor operators, and one relief man for normal operation and all the former plus a Duty Technical
- 1 Advisor for emergency operation.
It is assumed that, during an aceluent, other plant and NRC personnel admitte.d to the control room would bring their own equipment from elsewhere on-site.
(n)
Upon implementation of the new emergency plan on April 1,1981, a bottle of potassium iodine tablets will be stored in the control rcom.
A minimum of 50 tablets will be provided.
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3.
Onsite Storage of Chlorine and Other Hazardous Chemicals See Section IV.
4.
Offsite Manufacturing, Storage,-or Transportation Facilities for HazardoE5" Chemicals There are no known manufacturing, storage, or transpor-tation facilities for hazardous chemicals within a five-mile radius of PBNP.
See Section IV.
5.
Technical Specifications (a)
Chlorine detection is not required at PBNP.
(b)
Technical Specifications for the periodic testing of control room emergency filtration are attached.
6.
Other Parameters (a)
The source term is based on operation at 1518.5 MWt for 500 days.
Radioactivity available for release includes 100% of core noble gases and 25% of core iodines of which 85% are elemental and 15% are organic (methyl).
(b)
Containment leak rate is assumed to be 0.4% per day for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and 0.2% per day thereafter.
(c)
Control room meteorology and occupancy is assumed as follows:
Wind Speed Direction Occupancy Effective 3
Time Factor Factor Factor X/Q (sec/m )
0-8 hr.
1 1
1 2.15 x 10-3 8-24 hr.
0.8 0.85 1
1.46 x 10-3 1-4 day 0.57 0.71 0.6 5.16 x 10-4 4-30 day 0.36 0.41 0.4 1.29 x 10-4 III.
RADIOLOGICAL EVALUATION
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Both Modes III and IV were analyzed.
For Mode IV, infiltration rates of both 0 and 10 cfm were analyzed.
While some infil-
)
tration may be possible due to the opening and closing of doors, we consider 10 cfm to be an overly conservative estimate of this amount..
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Charcoal filter beds of 2" depth are provided for the control room at PBNP.
Technical Specifications provide for periodic testing of the filters to assure that a removal efficiency of 99% is obtained for elemental iodine and a removal efficiency of 90% for organic (methyl) iodine.
Since testing at PBNP for the last four years has indicated consistent results for methyl iodine in excess of 99%, we have also evaluated radiological habitability using a conservative efficiency of 95% for methyl iodine.
The results of the accident dose assessment are given in Table 1.
Based on the well-known blocking effect of potassium iodide (KI), especially as described in NCRP Report No. 55, KI tablers will be provided in the control room at PBNP.
Approval for the use of this compound by our employees has been obtained from the Company Medical Department.
Protection factors afforded by KI for 100 mg administration have been noted from 20 to 1,000, with lower protection factors if administered more than two or three hours after ex7osure.
Since KI is available in the control room, administration of a single dose can reasonably be expected in substantially less than two hours after commencement of exposure.
For this evaluation, a protection factor of 10 has been conser-vatively assumed.
Recent studies of Los Alamos and Oak Ridge National Laboratories indicate that radiciodine releases in nimlear accidents are substantially less than previously assumed.
The Nuclear Safety Oversight Committee in its December 21, 1980 letter to President Carter recommended that "the Nuclear Regulatory Commission and the U. S. Department of Energy should be responding more aggressively to this important development."
In a recent paper published by the Electric Power Research Institute and entitled " Realistic Estimates of the Consequences of Nuclear Accidents", authors M. Levenson and F.
Rahn have noted iodine partition factors ranging from 6 to 105 Levenson and Rahn pointed out that in the SL-1 and Windscale Accidents, the attenuation factors were approximately 103; for TMI-2, the attenuation 5
l factor was about 6 x 10.
For purposes of the control room evaluation, a factor of 200 was conservatively assumed.
The gamma and thyroid doses shown in Table 1 meet the requirements of Appendix A to 10 CFR Part 50.
The beta dose is approximately 55 Rem, and both eye protection and protective clothing will be provided in the control room to meet the requirements.
.w-Cont:ol room shielding at PBNP was also analyzed for direct radiation originating from either containment.
The walls of the control room consist of 18" of concrete.
The 30-day dose rate in the general area of the control room was calculated to be about 0.3 mrem (0.0003 Rem).
As shown in Figure 2, small triangular areas in the northeast and south-east corners of the control room exhibit higher doses on the order of 4.8 Rem due to angular radiation streaming through the doors and small windows next to the doors.
These are not normally occupied areas of the control room except for ingress and egress.
Contribution to gamma doses from a semi-infinite gas cloud surrounding the plant were also calculated.
These calculations conservatively predict the control room 30-day gamma dose from the gas cloud to be a maximum of 96 Rem.
This dose exceeds the 10 CFR Appendix A permissible dose and is due, in large measure, to the radiation shine through the control room doorways and window.
The integrated 30-day gamma dose, if one were to assume the control room walls were all concrete, would be limited to 0.82 Rem.
Accordingly, we are designing portable radiation shielding which could be placed in front of the control room doorways and windcws which would limit the 30-day control room gamma dose from the gas cloud around the plant to 2.2 Rem.
This would restrict the total 30-day control room gamma dose to the 5 Rem limit specified in Criterion 19 of 10 CFR 50 Appendix A.
IV.
HAZARDCJS CHEMICALS A survey was conducted to identify any sources of hazardous chemicals or toxic gases on-site or within five miles.
The survey was conducted in accordance with the criteria established by Regulatory Guides 1.70 and 1.78 and by the Standard Review Plan.
There are no facilities utilizing hazardous chemicals or toxic gases within five miles of the plant site.
In fact, there are no significant industrial facilities of any type within this area which is, except for PBNP and the neighboring Kewaunee Nuclear Power Plant, devoted exclusively to agriculture.
1 In addition to the survey for industrial facilities, the local gas company was contacted to confirm that there are no gas distribution or transmission pipelines within a five-mile radius of the site.
There is one transportation corridor within five miles of l
the plant, namely State Highway 42.
This traffic route is 1.5 miles from the site at its nearest point.
Since enere l
is no identified terminus for hazardous chemicals within a five-mile radius, there is no basis for assuming frequent chipments along this route.
Furthermore, Highway 47 ls not l
a logical transportation route to any major indust:;33 area such as Green Bay, Appleton, Sheboygan, or Milwaukee.
No frequent shipments have been noted by employees who reside in the area. -
The nearest rail line and the nearest Great Lakes shipping channel are both beyond the five-mile radius of PBNP.
i Consideration was given to the residential delivery of propane and the infrequent (one or twice a year) use of liquid ammonia for fertilization of farm fields.
Analysis of a spill from a propane tank truck was presented in the PSAR Site Addendum for the Haven Nuclear Plant (application now withdrawn).
This analysis is equally applicable for the PBNP site and demonstrated that no explosion hazard extends beyond 2,100 ft.
and that a flammable cloud could not reach 2,900 ft. from the spill.
The use of liquid ammonia in quantities expected
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for local use on farm fields (500 gallon tanks) does not exceed the values permitted in Table C-2 of Regulatory Guide 1.78.
Again, the infrequent use of such materials in the vicinity of the site also precludes their consideration.
Several on-site sources of potentially hazardous chemicals or toxic gases have been identified.
The hazardous chemicals 1
sources are the sulfuric acid storage tank, located in the vicinity of the water treatment plant (maximum of 5,700 gallons), and the sodium hydroxide storage tank located in the auxiliary building (maximum 5,100 gallons).
Gaseous storage consists of nitrogen, carbon dioxide, and hydrogen.
While these gases are not of themselves toxic, oney represent potential asphyxiants and, in the case of hydrogen, constitute an explosion hazard.
Because of their low volatility and distant lccation in the plant, the sulfuric acid and sodium hydroxide storage facil-ities are not of concern for control room habitability.
The hydrogen and nitrogen tanks are located ~1tside and north of the turbine building and similarly a not represent a potential concern for control room habitan lity.
Carbon dioxide is used in the gas turbine building in the fire suppressor system and is also used to purge the main electric generators of hydrogen.
The physical locations of these storage tanks and the quantity of gas in storage preclude any effect on the control room.
i It is therefore concluded that toxic gas accident analysis for potential hazardous chemical releases on or within five miles of the plant site are not necessary for PBNP.
Similarly, no modification of the control room habi tability system or instal-lation on local or remote toxic gas detectors is necessary.
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FIGUltE 2 GENERAL ARRANGE!ENT OF CONTROL ROOM AND CONTAINMENTS AT POINT BEACH HUCLEAR PLANT l
(Shaded areas indicate corners affected by direct radiation shine from containments.)
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UNIT 1 CONTAINMENT UNIT 2 CONTAINMENT
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4 000R DOOR Scale - 1" = 50 ft.
TABLE 1 CONTROL ROOM IIABITABILITY ACCIDENT DOSES POINT BEACil NUCLEAR PLANT Case Opera tion Makeup Recirc.
Infiltration Elem. I Methyl I Dose, Rem No.
Mode cfm cfm cfm Removal Removal Gamma Beta Thyroid 1.
III O
4950 3312 99 90 2.79 55.2 5.110 2.
III O
4950 3312 99 95 2.79 55.1 4.970 3.
IV 4950 0
0 99 90 2.81 55.1 1.080 r
4.
IV 4950 0
10 99 90 2.81 55.1 1.110 l
S.
IV 4950 0
0 99 95 2.80 55.0 0.548 6.
IV 4950 0
10 99 95 2.80 55.0 0.572 i
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l 15.3.12 CONTROL ROOM EMERGCICY FILTPATION i
i Applicability Applies to the cperability of the control rocn emergency filtration.
Objective
'Ib specify functional requirements of the control room emergency 2iltration i
during power operation and refueling operation.
Specificatien 1.
Except as specified in 15.3.12.3 below, the centrol room emeroency filtration system shall be operable at all times during power operation and refueling operation of either unit.
2.
a.
The results of in-place cold DOP and halogenated hydrocarben tents, conducted in accordance with Specification 15.4.11, on HEPA filter and charcoal adsorber banks shall show a minimum of 99% DOP removal and 99% halogenated hydrocarbon rer. oval, b.
The results of laboratory charcoal adscrbent tests, conducted in accordance with Specification 15.4.11, shall show a uinimum of 90s removal cf methyl iodide.
If laboratory analysis results for in-j place charcoal indicate less than 90s methyl iodide removal, this specification may be met by replacement with charcoal adsorbent j
which has been verified to achieve 90% minimum removal and which has been stored in sealed containers, and retesting the charcoal 1
adsorber bank for halogenated hydrocarben removal.
c.
Tne results of fan testing, conducted in accordance with specifica-tion 15.4.11, shall show operation within + 10% of design flow, i
1 15.3.12-1 Unit 1/ Unit 2 May 27, 1975 1
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I 3.
Fron the date that the control room emergency filtration is made or found to be inoperable, reactor operation or refueling operation of either unit may be continued only during the succeeding seven days, unless the system is sooner made operable.
4.
If the conditions of 15.3.12.3 cannot be met, the operating reactor (s)
I shall be brought to cold shutdown conditions within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> and refueling operations shall be terminated as soon as practicable.
Basis The control room emergency filtration is designed to filter control rocm I
atmosphere and makeup air during control room isolation conditions. High 4
efficiency particulate (HEPA) filters are installed before the charcoal adsorbers to prevent clogging and to remove essentially all particulate material. Charcoal adsorbers are installed to reduce the potential intake of radioactive iodine to the control room during accident conditions.
If the system is found to be inoperable, there is no immediate threat to the control room and operation may continue for a limited period of time.
4 15.3.12-2 Unit 1/ Unit 2 May 27, 1975
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0 15.4.11 CONTROL ROOM EMERGCICY FILTFATION
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Applicability i
Applies to periodic testing requirements of the centrol room emergency filtra-tion equipment.
Obj ective To verify the operability of the control room emergency filtration and its ability to remove radioactive contaminants when required.
Specificatien 1.
At least once per year the pressure drop across the combined HEPA filters and charcoal adsorber banks shall be demonstrated to be less
. than 6 inches of water at design flow rate.
2.
The control room emergency filtration automatic initiation shall be demonstrated once per year.
3.
The control room emergency filtration shall be cperated at least 10 l
hours every month.
I 4.
Components of the control room emergency filtratien shall be tested as follows:
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a.
HEPA filters and charcoal adsorbers shall be tested and analyzed at least once per year, or after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of operation since the previous test, and following significant painting, fire or chemical release in the control roem during filtration cperation, b.
Cold CCP testing of the HEPA filter bank shall be performed after each ecmplete or partial replacement of HEPA filters, or after any structural maintenance on the filter housing.
DCP testing shall be at design velocity + 20%.
i 15.4.11-1 Unit 1/ Unit 2 May 27, 1975 1
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c.
Halogenated hydrocarbon testing of the charcoal adsorber bank shall be performnd after each complete or partial replacement of charcoal adsorbers or.after any structural maintenance of the adsorber housing.
Halogenated hydrocarbon testing shall be at design velocity + 20%.
d.
Laboratory sample analysis of in-place charcoal adsorbent shall be performed at least once per year for standby service or after every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation and, as a minimum, shall be 3 inlet conducted at velocities within 20% of design, 0.05 mg/m iodide concentration, 95% relative humidity and 125*F.
e.
Fans shall be tested at least once per year or after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of operation since the previous test, and following fan maintenance or repair.
Basis The control room emergency filtration system is designed to filter the control room atmosphere and makeup air to the control room during control room isolation conditions. The control roem emergency filtration is nor= ally isclated and not in operation and testing more frequently than that specified is not required to insure operability or performance. If the efficiencies of HEPA and charcoal adsorbers are as speci'ied, the resulting control room doses during accident conditions will be less than allowable levels in i
Criterion 19 of Appendix A to 10 CFR 50.
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15.4.11-2 Unit 1/ Unit 2 May 27, 1975 l