NSSA Response to BBC Article "The Ship That Totally Failed to Change the World"
N/S Savannah Association, Inc. 8/8/2014
For immediate release
On July 25, 2014, BBC News Magazine published a feature piece on NS SAVANNAH entitled "The Ship That Totally Failed to Change the World." The N/S SAVANNAH Association, Inc. was contacted during the production of the article, and interviews were conducted with Stan Wheatley and Will Davis. While the bulk of the article is accurate, and NSSA welcomes and appreciates the media attention, certain points contained in the article are not necessarily accurate.
The question of the primary coolant discharge overboard during the early years of the ship's operation was asked, and a detailed answer provided. None of the answer, emailed to BBC's Justin Parkinson, was included in the article, which when printed simply stated that overboard discharges (of radioactive water) were reduced when greater tank capacity on board was installed, which is not accurate. In order to ensure that the complete story as to the overboard discharges during the first few years of operation is told, the explanation as e-mailed is reproduced here:
- As first constructed, the primary plant (nuclear steam supply system) on board NS SAVANNAH (hereafter, "NSS") was found to have a leak rate which at times depending upon operations and testing could amount to up to 1200 US gallons per day, although often it was much lower. It's important to understand that this was reactor coolant - which itself is highly purified water.
From the FSAR (Final Safety Analysis Report) for the ship, STS-004-002, section 7.1.2 we obtain the following:
- "During the NSS's operational period, most of the leakage from the primary system was from the buffer seal (SL) system reciprocating charge pumps and from the diaphragm-operated relief valves. Maintenance techniques for the buffer seal charge pumps (which took suction downstream of the primary system demineralizers) were steadily improved. Improvements in the design and testing sequence of the relief valves reduced the leakage. As a result of these improvements, leakage was reduced from a maximum of 1200 gpd [gallons per day] to 50-100 gpd. Leakage from the buffer seals of the control rod drive shafts and from the valve stem packing was always well within acceptable and anticipated limits."
(The buffer seal system described above provided a positive inflow of water into the reactor through the control rod drive shaft seals, preventing leakage out of them; the diaphragm operated relief valves are overpressure protection for the reactor plant. The implication of the buffer seal pumps taking suction downstream of the demineralizers is that the water is highly purified after having passed through them; thus, any leak off is purified as well.)
The process was that accumulated leaked coolant was stored in tanks. Prior to discharging this liquid , the tanks were sampled to ensure they were within Federal (US 10 CFR 20, Table II, MPCW) limits. After this was guaranteed, the water was safely discharged at sea.
Significantly radioactive material, such as ion exchanger resin or any such, was not discharged at sea but rather at approved facilities such as that at Todd Shipyards, Galveston Texas or else onto dedicated servicing barge NSV ATOMIC SERVANT. No solid materials were dumped at sea.
At the end of the BBC article, it is stated that future acceptance of nuclear ships "might require more than a publicity trip or two," with the direct implication that this is all that NS SAVANNAH achieved during her tours around the world. In point of fact, operation of SAVANNAH led to visits to over 30 domestic and 40 foreign ports, during the demonstration period the first few years of the ship's operation, and following that during the five years of commercial operation. During this entire time period, the availability of the power plant (the amount of time it was actually available, versus the amount of time it was scheduled to be) was 99%. NS SAVANNAH had a history, and performance record, that any future nuclear merchant ship would do well to duplicate.
Communications Director, N.S. Savannah Association
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