ML20137M109
| ML20137M109 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 01/15/1986 |
| From: | Walker R PUBLIC SERVICE CO. OF COLORADO |
| To: | Berkow H Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20137M114 | List: |
| References | |
| P-86016, TAC-59787, TAC-59789, NUDOCS 8601280193 | |
| Download: ML20137M109 (6) | |
Text
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PUBLIG SERVICE GOMPANY OF GOLORADO P.
O.
BOX 840 OENVER.
COLORADO C0208 R. F. WALKE R PPESCENT January 15, 1986 Fort St. Vrain Unit No. 1 P-86016 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Attn: Mr. H.N. Berkow, Project Director Standardization and Special Projects Directorate Docket No. 50-267
SUBJECT:
. Addihonal Information to Support 35% Power -
Building Access
REFERENCE:
- 1) PSC Letter Dated December 10, 1985, Walker to Berkow (P-85460)
Dear Mr.~ Berkow:
This letter submits additional information to support PSC's intention to use the ice vests described in reference 1 to allow personnel access with elevated building temperatures. As stated in Reference 1, PSC may rely on the ice vests to perform various desirable actions following a steam line break with the Fort St. Vrain (FSV) Plant at 3
35% power or less. However, it should be re-emphasized that use of Jg the ice vests would not be mandatory following a steam line break at 35% power because adequate time exists (29.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) prior to the time
- o n.
58 that PCRV liner cooling must be established.
o In response to recent NRC staff requests, Attachment I to this letter 96 documents the professional opinion of Dr.
Thomas Bernard who has g@
worked for two years on the development of a Heat Stress Management m<
Program for EPRI. Attachment 2 to this letter provides details of a 9!
FSV Operations Department walkdown of the manual actions which would gg be performed following a steam line break.
It is concluded that an m a.c.
adequate supply of ice vests and Scott Air-Paks exist to perform the required manual actions to establish liner cooling in elevated building temperatures.
Additional ice vests are being ordered to d
provide further m rgi
+ 4 4
Again, 'PSC w'uld like to stress that we have a proven safety program o
i and will do the utmost to protect the safety ~of all workers.
The work would be done by teams and in stages, with stay times being short (less than 30 minutes).
If you have any questions on this subject, please call
.Mr. M. H. Holmes at (303) 480-6960.
j Very truly yours, R lY. u) aLLr R.F. Walker President i
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Attachment I to P-86016
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'412 2 2 1000 January 13, 1986 Michael Niehoff Public Service Company of Colorado 2420 W. 26th Avenue - Suite 100D Denver, CO 80211 Dear Mr. Niehoff My opinion van sought concerning an emergency entry procedure at Fort St. Vrain in response to an NRC inquiry. A basic concern for entering the reactor building when the ambient air tecperature in as high as 82 C (180 F) and in saturated with water vapor is the heat stress ~ that the worker will experience.
I have prepared a rencarch report for EPRI titled " Heat Stress Managerent Program f or the Nuclear Power Industry,"
which will be available as EPRI NP4453 in March. A prepub11 cation copy in enclosed.
This letter discusses your situation in the light of the EPRI research project.
Based on the report, ice cooling garments,-which are a type of personal protection, are the only practical means of protection.
These are described in Section 8.2 (pp 8-9f f).
The principle of personal protection is to provide the user with a hospitable microenvironment when hazards exist in the ambient environment.
Under conditions of high heat stress and moderate cetabolism with a need for mobility, an ice cooling gcrmant can provide the personal protection the workers require.
The ice garment controls hcat stress by limiting the external heat load on the worker and providing a heat sink for internal heat generation.
First, the insulating jacket on the garment and the coveralls worn by the individual will entablish a barrier to external heat gain f rom convection and radiation (inf rared). This means that internal heat generation is the primary source of heat stress.
Internal heat generation in metaboltam that results f rom the work demands placed on the individual. Because the clothing innulation and environmental conditions preclude sweating an an ef fective means of cooling the l
individual. the ice acts as a heat sink for internal heat generation to keep the body temperature within saf e itmits. Thun the ice garraant sets up a micruenvironment in which the external sourecs of heat are reduced and the internal heat is balanced by a heat sink.
The ice garments have been demonstrated as effective by both laboratory and field expertence. The highest ambient temperature in a laboratory that the ice garments have been tested was reported in EPRI NP2868. At 55 C (131 F), the ice cooling garment (SFWG in the report) permitted an average time.of 103 minuten and at least 67 min for 95% of the testa.
Beceune the use of personni protection for heat acress in based on the
principle of isolating the individual f rom 'the environment, increasing the ambient temperature should have little ef f ect on the work tinc.
Most field experience is at lower ambient temperatures, but two routine uses of ice garnents were reported to me at higher temperatures. In one, work is performed at 60 C (140 F) f or one hour bef ore the exposure is terminated by the procedure.
In this case, the workers have not f elt that they were Itmited by heat stress.
In the second case, work is performed for 15 to 25 minutes at 71 C (160 F).
The work in this case requires only that arount of time, and the workers also report that they are not limited by heat stress.
Based on laboratory and field experience, the nervice tiec for ice cooling garments van conservatively estimated and reported in NP4453 (sce Table 8-2, pg 8-13). For a garment with 3.8 kg (6.4 lb) of ice, a service of 45 minutes can he expected for a moderate ectabolfsm. Most experience has shown that longer times can be expected (e.g., the 60 minuten at 60 C ncntioned above).
The following are recommendations f or the ercrgency entry work.
o Ice cooling garment with at least 3.8 kg of ice at -6 C (20 F) o SCBA (Notei the service time may be dif f erent than that f or the ice garment, and the shorter time would apply f or planning purposes) o One set of heavy cotton coveralls (an outer cover of plastics would enhance the insulating effects) o Buddy system f or entual observation o Physically fit workers o Instructions to terminate the work at the earliest signs of heat illness o Heat resistant gloves Two other considerations night include an antif ogging agent on the exterior 3 ens of the SCBA nask and a communications device between the two workers and to the outside.
The above information is an interpretation of the caterial contained in the CPRI report and is provided with the understanding that it is covered by the legal notice contained in the report.
Sincerl
]
C homas Q. Bernard Human Sciences