ML19344D165
| ML19344D165 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 03/06/1980 |
| From: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0578, RTR-NUREG-578 NUDOCS 8003110455 | |
| Download: ML19344D165 (3) | |
Text
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CONNECTICUT YANKEE AT O MIC POWER COMPANY BERLIN. CONNECTICUT P O. BOX 2 70 H ARTFORD. CON N ECTICUT O t01 T E L E Pos c h 8 acrese-esu March 6, 1980 Docket No. 50-213 Director of Nuclear Reactor Regulation Attn:
Mr. D. L. Ziemann, Chief Operating Reactors Branch #2 U. S. Nuclear Regulatory Commission Washington, D. C.
20555
References:
(1)
W. G. Counsil letter to H. R. Denton dated November 21, 1979 (2) NUREG-0578
'IMI Lessons-Learned Task Force Status Report and Short-Term Reconmendations.
(3)
H. R. Denton letter to All Operating Nuclear Power Plants dated October 30, 1979 Gentleien:
Haddam Neck Plant Containment Water Level Indication In Reference (1), Connecticut Yankee Atomic Power Company (CYAPCO) provided its commitment to comply with the Staff requirement to install containment water level indication as indicated in Requirement 2.19 of References (2) and (3). Although Reference (3) cate6orizes this item e.s implementation review, CYAPCO has discussed the unique characteristics of the Haddam Neck Plant with the NRC Staff to ensure that an acceptable installation would evolve. CYAPC0 believes that an understanding which deviates from the above referenced Staff requirements has been reached with the Staff and the purpose of this letter is to formally document CYAPCO's plans, and ensure Utaff concurrence, prior to implementation presently scheduled for the upcoming refueling outage.
The deviation from Staff requirements currently planned is to not upgrade the narrow range containment water level instrument to the requirements of Regulatory Guide 1.89 as required by Clarification (3) on Page 44 of Reference (3). The initial motive for ascertaining the necessity of this upgrading require-ment was the significant man-rem expenditure which would result. During previous outages, measurements indicated that radiation levels in this sump were in the range of 25 R/hr. On the lowest level of containment in the vicinity of the sump, the levels were in the range of 0.5 R/hr. The installation of a qualified instrument in this sump is estimated to require approximately 120 man-hours, most of which would be required vithin the small sump, thereby resulting in a significant man-rem expendittu e.
S'C O 3 ll o+55
- Through discussions with the Staff, it is CYAPCO's understanding that the promulgation of this narrow-range measurement requirement by the Staff is based on the NRC's evaluation that significant quantities of liquid would be collected in these smaller sumps prior to any level indication on a wide-range device.
In the case of the Haddam Neck Plant, the sump in question is only approximately four feet deep and has a maximum capacity of only approxinately 2,000 gallons.
During any postulated loss-of-coolant accident, this sump would be filled very rapidly, thereby justifying the proposed deviation.
CYAPCO intends to install redundant qualified, wide-range water level instru-ments in accordance with Clarifications (2) and (h) of Reference (3). The range of these instruments will be approximately 600,000 gallons, which is well above the volume which could reasonably be expected to occupy the lowest elevation of the Haddam Neck Plant. The design of the containment building is such that once the capacity of smaller sump is reached, water would occupy the entire floor of the lowest elevation of the containment. The 600,000 gallon volume corresponds to a height of approximately 77 inches. There is a small lip adjacent to the 2,000 gallon sump such tha? the vide-range instruma + - will be on-scale as soon as the narrow-range inst ument indicates maximum inventory in the smaller sump. Therefore, there is no gap in the range between the narrow-and wide-range instruments.
The rationale of CYAPCO's intentions is summarized as follows:
(1) The existing narrow-range instrument cannot be qualified to conform to the requirements of Regulatory Guide 1.89 (2) Sigr.ificant man-rem expenditures would be required to install a qualified instrument.
1 (3) The capacity of the existing sump is small, only 2,000 gallons; during accident conditions, it would become full relatively early in any loss-of-coolant scenario.
(4) During power operation, the existing narrow-range instrument is normally on-scale; its reliability has been demonstrated by many years of successful operation.
(5) This existing instrument is calibrated once per refueling outage in accordancu with Technical Specifications.
(6) The existing transmitter is provided with semi-vital power, via MCC-5, and is backed up by the on-site emergency diesel generators.
(7) The redundant, qualified, vide-range instruments will be on-scale as soon as the narrow-range instrument indicates maximum level.
i H
N The above reasons su:rmarize the basis of CYAPCO's decision to not fulfill the requirements of Clarification (3) of Reference (3).
Based upon discussions with the Staff, it is CYAPCO's understanding that this approach is acceptable.
Installation of the vide-range instruments is planned for the refueling outage.
Should the above understanding be incorrect, please advise to that effect prcmptly.
Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY 49
//., l. f 0 '/?fk '
W. G. Counsil Vice President
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