ML20209D245
| ML20209D245 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 04/22/1987 |
| From: | Hunsader S COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| 2960K, NUDOCS 8704290214 | |
| Download: ML20209D245 (2) | |
Text
7--
m c
Commonwealth Edison
.u : One First Nabonal Plaza, Chcago, Illinois Wodress Reply to: Post Omc2 Box 767
'. ' Chicago, Illinois 60690 0767 April 22, 1987 Mr. Thomas E. Murley U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, DC. 20555
Subject:
Braidwood Station Units 1 and 2 Removal of Control Room Chlorine Detectors Backfit Evaluation Under 10CFR 50.109 NRC Docket Nos. 50-456/50-457
Reference:
(a) June 3, 1986 A.D. Miosi letter to H.R. Denton (b) December 23, 1986 S.C. Hunsader letter to-H.R. Denton (c) March 4, 1987 S.A. Varga letter to D.L. Farrar (d) April 2, 1987 S.C. Hunsader letter to H.R. Denton
Dear Mr. Murley:
The purpose of this letter is to provide Commonwealth Edison's response to reference (c) and explain Commonwealth Edison's position with respect to a requirement presented in that document. Specifically, Commonwealth Edison takes exception to the requirement to demonstrate, on an annual basis, that the control room envelope integrity is maintained, since there is currently no regulatory requirement to do so.
Imposition of this new requirement is considered to be a generic backfit item that should be reviewed under 10 CFR 50.109.
Reference (a) provided Commonwealth Edison's initial evaluation using the guidance of Regulatory Guide 1.78, to justify the removal of the chlorine detectors from the Braidwood Control Room HVAC system. Reference (b) provided notification that emergency planning measures had been established with Will County, Illinois in the event of a chlorine accident in the vicinity of Braidwood Station. Reference (c) provided the NRC staff review and evaluation of the commonwealth Edison submittals and authorized the removal of the chlorine detectors based on (1) the small probability of a chlorine. event, (2) our commitment to maintain prompt notification communications with Will County, (3) a requirement to isolate the control room upon receipt of notice of a toxic gas incident, and (4) a requirement to demonstrate control room integrity on a routine basis. Reference (d) provided Comunonwealth Edison's commitment to provide manual isolation capability of the control room envelope and to subsequently demonstrate this isolation capability on an 18-month basis, thereafter, via a Technical Specification surveillance. Reference (d) also included a description of Commonwealth Edison's evaluation of maximum air "in leakage" into the control room as determined using Regulatory Guide 1.78.
N 8704290214 870422 S.D PDR ADOCK 05000456 V
P PDR
.\\
1
. Reference (c), in part, states the following:
"..... include a procedure to demonstrate on an annual basis, that the control room envelope integrity is maintained, i.e.,
infiltration into the control room envelope in the isolation mode does not negate the toxic-gas analysis and thus, the capability to protect its operators."
Regulatory Guide 1.78 requires that air infiltration into the control room be considered from an analytical standpoint. Regulatory Guides 1.78_and 1.95 provide no requirement to annually demonstrate that_the control room integrity is maintained during the isolation mode. Also no such requirement has been imposed at Commonwealth Edison's other nuclear stations. Similarly, to the best of our_ knowledge no other nuclear station has been required to perform such a demonstration.
Retaining the chlorine detectors in place, which would provide automatic isolation, would not provide an answer to the air "in leakage" question. Air "in leakage", subsequent to control room isolation, is a separate matter from the discussions on the capability of the control room to be isolated, whether manually or automatically.
10CFR50.109(a)(1) states in part: "Backfitting is defined as the modification of or addition to systems, structures, components or design of a facility,...or the procedures or organization required to design construct or operate a facility; any of which may result from a new or amended provision in the Comnission rules or the imposition of a regulatory staff position interpreting the Commission rules that is either new or different from a previously applicable staff position...".
10CFR50.109(a)(2) states inpart:
"The Commission shall require a systemmatic and documented analysis...for backfits it seeks to impose".
10CFR50.109(a)(3) states inpart:
"The Commission shall require the backfitting of a facility only when it determines, based on the analysis...that there is a substantial increase in the overall protection of the public...and that the direct and indirect costs of implementation for l
that facility are justified in view of this increased protection".
L The proposed control room integrity demonstration in reference (c) is considered to be a modification of or an addition to the procedures required to operate Braidwood station, and is considered to be a new staff position. Also, the proposed demonstration test does not present a_
substantial increase in the overall protection of the public. As such this matter is considered to be a backfit and should be evaluated under the rules of 10CFR50.109.
Please address any questions concerning this matter to this office.
S. C. Hunsader Nuclear Licensing Administrator cc:
J. Stevens NRC Resident Inspector-Braidwood 2960K
,, _._ _.~..,_.._- _ _ _..~ - _.- -._