ML20136F313
| ML20136F313 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/20/1985 |
| From: | Standerfer F GENERAL PUBLIC UTILITIES CORP. |
| To: | Travers W Office of Nuclear Reactor Regulation |
| References | |
| 0358A, 358A, 4410-85-L-0231, 4410-85-L-231, NUDOCS 8511220090 | |
| Download: ML20136F313 (7) | |
Text
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CPU Nuclear Corporation g
gf Post Office Box 480 Route 441 South Middletown, Pennsylvania 17057 0191 717 944 7621 TELEX 84 2386 Writer's Direct Dial Number:
(717) 948-846L 4410-85-L-0231 Document ID 0358A November 20, 1985 TMI Program Office p
- l Attn
- Dr. W. D. Travers a
G Acting Director
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US Nuclear Regulatory Commission c/o Three Mile Island Nuclear Station
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E5 Middletown, PA 17057 D
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Dear Dr. Travers:
Three Mile Island Nuclear Station, Unit 2 (TMI-2)
U Operating License No. OPR-73 Docket No. 50-320 Technical Specifications Change Request 49 and Recovery Operations Plan Change Request 31 - Response to NRC Comments Attached are responses to NRC comments on GPU Nuclear Technical Specifications Change Request (TSCR) 49 and Recovery Operations Plan Change Request (ROPCR) 31 forward via NRC letter NRC/TMI-85-060, W.D. Travers to F.R. Standerfer, dated October 2, 1985. The TSCR 49 and R0PCR 31 were submitted via GPU Nuclear letter 4410-85-L-0110 dated June 18, 1985.
Sincerely,
/Y W
. Standerfe Vice President / Director, TMI-2 FRS/RdS/eml Attachment A fd9 8511220090 851120 PDR ADOCK 05000320 8
P PDR GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation
i ATTACHMENT (4410-85-L-0231) 1 COMMENT 1 Describe your program for controlling the use of respirators and minimizing t.~i.r impact on communications. Your discussion should include equipment, training, and results achieved.
GPU NUCLEAR RESPONSE Control of the use of respirators is achieved through the Respiratory l
Protection Program, Procedure 9000-ADM-4020.01 and related support procedures. The primary goals in controlling the use of respirators are to ensure that the respirator provides adequate protection to the wearer and that respirator use does not pose a hazard to the individual. This is accomplished in the following manner:
1.
Training All individuals who utilize respiratory protection at TMI must successfully complete Respiratory Protection Training every 365 days. The training consists of a core lecture that covers a wide variety of respiratory protection topics, including physiological considerations, potential contaminants, limitations and precautions, and respirator use under unusual or emergency conditions. In addition, each user must demonstrate the proper use of each of the devices for which qualification is sougnt during a practical factors examination that follows the lecture.
2.
Fit Testing All users of facepiece respirators are required to pass a quantitative fit test every year for each type of mask for which qualification is sought. The criterion for passing the fit test for a full facepiece respirator is no peak facepiece leakage in excess of 1% during the eight standard exercises prescribed in NUREG 0041. This equates to a protection factor greater than 100, significantly higher than the credited protection factor of 50 for negative pressure full facepiece, air purifying respirators. More detailed information can be found in TMI Procedure 9000-ADM-4020.05.
3.
Medical Qualification All respirator users are examined by a physician every year to determine that the individual is physically and psychologically able to perform tasks using a respirator. Medical examination protocol is specified in the GPUN Medical Plan 1000-PLN-1100.01.
4.
Equipment Currently, there are over 200 full faceplece respirators, equipped with iodine /HEPA filter canisters, stored in emergency kits on site. At least twenty-five of these devices are maintained in the
ATTACHMENT (4410-85-L-0231)
TMI-2 Control Room in accordance with AP1057. In addition, there are 1000 extra canisters of this type stored in the warehouse.
These emergency use devices are inspected by techniques which are specified in TM1 Procedure 4213-ADM-4020.01.
5.
. Communications Although canmunications are hampered by wearing respiratory protection devices, experience in the working environment has demonstrated that workers can communicate effectively on the job and even over the telephone. Although not a daily occurrence, workers must periodically communicate with the Control Room using the plant page system. This has not caused unusual problems. The majority of the full facepiece, air purifying respirators used at TM1 are equipped with speaking diaphragms which, from our experience, permit adequate communications during respirator use.
COMMENT 2 It is not clear from your submittal wnat fraction of the iodine you are assuming in your accident scenaric is in particulate, organic, elemental, etc. form; please clarify your source term assumptions. Wnat are your plans for the use of adsorbents to protect against iodine? Do you intend to. apply for such an exemption; if so when? The information provided by iodine protections would be required.
GPU NUCLEAR HESPONSE The analysis of doses to Control Room Operators presented in Technical Specification Change Request (TSCR) #49 conservatively assumed the standard distributions provided in regulatory guidance (Regulatory Guide (Reg. Guide) 1.4, " Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Pressurized Water Reactors"). Twenty-five percent (25%) of the total core iodine inventory was assumed to be available for leakage from containment and was released. Further, it was assumed that the chemical form of the released iodine was as 91% elemental iodine, 5% particulate iodine and 4%
organic lodides.
Although Reg. Guide 1.4 specifies this chemical form for iodine release as a result of a LOCA, the form is specified for the accident consequences at the involved unit (i.e., Unit 1 in this case). Note that the distribution of chemical forms presented in the Reg. Guide is a recommendation; the Reg. Guide specifically provides that other i
ecsumptions may be utilized on an individual case basis.
Therefore, we conclude that no exemptions are required for variance from these Reg.
Guide recommendations. Source term research over the past 5 years has clearly indicated that:
(1) the releases calculated with Reg. Guide 1.4 u
m
ATTACHMENT (4410-85-L-0231) assumptions are higher than realistic estimates as a result of neglect of natural attenuation processes'in containment; and (2) the mixture of chemical forms specified in Reg. Guide 1.4 is incorrect (i.e., the ratio of 1 -fraction to particulate fraction is too high).
(Ref. NUREG-0771, 2
NUHEG-0772, NUREG-0956). It should be noted that this analysis does not attempt to utilize less conservative source terms (i.e., research results reported in NUREG-0956), but assumes the standard and demonstrably conservative estimates of iodine releases specified in Reg. Guide 1.4.
It is only the second conclusion, i.e., a chemically correct mixture of iodine forms which is used in this analysis. The use of this conclusion does not anticipate the Staff's position with respect to adoption of less conservative source terms but is consistent with the NRC staff position stated in NUREG-0772, i.e., the Cs1 is the expected dominant form of iodine in the containment atmosphere. When this research finding, in combination with the conservative release fractions of Reg. Guide 1.4, is applied to anticipate the most appropriate TMI-2 response to a Unit 1 accident, it is apparent that protection against particulate forms of iodine is a dominant concern in protecting Unit 2 workers. This protection is provided by respirators, which have been demonstrated to provide a protection factor of 50 for particulate contamination.
Justification for the use of a Protection Factor (PF) of 50 for respirators in assessing the effects of a Unit 1 LOCA on the Unit 2 Control Room is based on 10 CFR 20.103 which recognizes a PF of 50 for particulates through a HEPA filter. This allowance applies to the HEPA filter associated with charcoal canisters for respirators. In addition, as discussed in TSCR #49, sufficient evidence is available to justify the application of a PF of 50, even for elemental iodines, based on practical experience and testing performed at various laboratories.
(References 9.7 and 9.8 of TSCR #49.) Since the canisters available in the Control Room are designed to protect against both particulates and elemental iodines, application of a PF of 50 in accident analyses is acceptable and consistent with the guidance in Section A of Reg. Guide 1.4; therefore, an exemption from 10 CFR 20.103 is not deemed to be required.
In addition, to the use of realistic source term assumptions, it should also be noted that there is a low likelihood of the simultaneous occurrence of a Unit 1 LOCA and a Loss of Offsite Power (LOOP) in l
Unit 2.
As discussed in TSCR #51 via GPU Nuclear letter 4410-85-L-0135 dated July 31, 1985, the offsite power grid supplying TMI is evaluated to be very reliable (e.g., TMI has never experienced a loss of offsite power event). In the unlikely event offsite power is lost, it is expected that the duration of loss would be short (NRC currently estimates the median time to restoration is 1/2 hour with 90% of all losses restored within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />). The probability of occurrence of a LOOP event at TMI-2 of duration greater than 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is very small (i.e., 5x10-4)
In summary, this analysis is based on the conservative release assumptions of Reg. Guide 1.4, but uses the most accurate available information in the response to the Reg. Guide releases.
(Note: This
ATTACHMENT (4410-85-L-0231) appears to be in keeping with long-standing NRC practice to use the most up-to-date technical information in response to accidents, rather than information known to be technically inaccurate.)
C0t44ENT 3 Describe your plans for assuring that personnel accessing the Control Room during an emergency have respirator qualification, fit proper respirator type in stock, eyeglass inserts, etc.
GPU NUCLEAR RESPONSE All personnel assigned duty as part of the emergency response team are required to be respirator qualified per Procedure 1501-POL-4020.02.
Personnel not specified as part of the emergency response team are directed to leave the Protected Area and muster at specified locations during an emergency. The GPU Nuclear respirator qualification program, described in TMI Procedures 1501-ADM-1100.01 and 9000-ADM-4020.01, includes classroom training, qualification on each type of respirator required, and quantitative fit test on each type of respirator required.
As part of the classroom training, personnel are trained in the individual aspects of respirator use. This includes use of properly fitting respirators, availability and use of eyeglass inserts, and provisions for physiological and psychological stress relief, should it occur. GPU Nuclear assures, per Administrative Procedure 1057, that sufficient numbers of required respirator types are available in the Control Room. A central location will be provided in tne Control Room for the storage of eyeglass inserts at the discretion of the employee.
j This will help assure availability of inserts during an emergency.
COMMENT 4 j.
Describe your provisions for physiological stress associated with long term (greater than two hours) use of respirators, especially assuming the Control Room chillers are inoperable. This should include a description j
of available relief crews and your experience with use of respirators in i
adverse conditions such as those that might occur with chillers inoperable.
GPU NUCLEAR RESPONSE inree Mile Island has had extensive experience with respirator use in a wide variety of conditions. The potential for significant physiological stress has manifested itself under some of these conditions. Typically, this potential occurs when individuals perform physically demanding work
ATTACHMENT (4410-85-L-0231) in heavy protective clothing at elevated environmental temperatures.
However, the conditions projected for the Control Room, even under worst case assumptions, do not indicate a physiologically stressful situation that could not be controlled relatively easily. The reasons for this assumption are as follows:
1.
There is a relatively long period of time (14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />) without chiller operation oefore temperatures in the Control Room would rise to the point tnat physiological stress would become a significant concern.
2.
The tasks performed by Control Room personnel would not be physically demanding. As a result, the physiological stress contribution from heat strain and respirator use should be acceptable; since the cardiovascular demand from the tasks being performed would be low. Additionally, the respirator physical assesses the wearers' capabilities to accommodate the cardiovascular demands imposed by the respirator and physical laoor.
3.
Heavy protective clothing would not be necessary in the Control Room environment. As result, the body's normal avenues of radiative, convective, and evaporate heat loss would not be inhibited.
4.
Calculations indicate that even under the worst case assumption of 1040F air temperatures in the Control Room, personnel utilizing respirators could work for a minimum of 60-90 minutes before any control measure would have to be implemented.
We have, at TMI, a well developed and experience-tested heat stress control program. Should the unlikely occur and conditions in the Control Room degrade to the point that physiological stress does become a concern, we are well prepared to evaluate and control it in the following manner:
1.
Our heat stress control program uses a sophisticated computer model that allows us to evaluate the physiological stress incurred under virtually cny set of environmental, work rate, and protective clothing conditions. The model allows us to calculate maximum stay times to prevent undue physiological stress and enables us to immediately assess the potential effectiveness of various control measures, if they become necessary, 2.
As part of our heat stress control program, we have also had extensive experience with the use of personal cooling devices.
Specifically, the Frozen Water Garment or Ice Vest, used with good success in the TMI-2 Containment Recovery Program, could be used to prevent excessive physiological stress to individuals working in the Control Room.
ATTACHMENT l
(4410-85-L-0231)
Additionally, the Operations staffing is such that for relatively short periods of time, i.e., a few days, it would be possible to schedule a four (4) hour watch instead the normal eight (8) hour watch. This shortened " watch period" would only be implemented during appropriate " emergencies" when, because of environmental conditions, this type action was deemed appropriate.
In summary, we have had a significant amount of experience with using respirators under far more extreme conditions than those anticipated in the TMI-2 Control Room. The programs, procedures, and equipment are in-place to deal effectively with this concern.
COMMENT 5 Since the safety evaluation assumes an infiltration of 1350 cfm you should either retain your current method of verifying the Control Room envelope is intact or a new surveillance should be developed for this purpose. Which strategy will be employed?
GPU NUCLEAR RESPONSE The method for insuring that the Control Room envelope is within the assumed bounds will t,a by performing a surveillance similar to the current method, i.e., perform a test that provides a known inlet volume and measure the resultant positive pressure. In this manner, it can be demonstrated that infiltration would not exceed bounded conditions.
COMMENT 6 If there is a problem with the ventilation system which brings its operability into question will you have a method of checking it quickly?
(Currently flow can be ascertained via Contro'. Room room readout. Will there be a method to determine if you are meeting the A pressure requirement?)
GPU NUCLEAR RESPONSE It is planned to maintain the present indications and alarms associated with the ventilation system. These include flow and Ap indication and Ap alarms. This instrumentation should be adequate to alert the operator of a potentially deficient condition and would allow appropriate action to be taken to verify the system was meeting OPERABILITY requirements, i.e.,
at least one exhaust fan operating and it was capable of maintaining at least 1/8" H O negative pressure.
2