Proposed pebble bed modular reactor

If the context theory is applied, tourists will clearly note the proposed structure from these roads. The awareness of regular viewers, who travel on the above roads regularly and at a speed, will become accustomed to the structure with time, until the element blends into the overall picture. The same principle would be applicable for people who work or stay in Duynefontyn, Van Riebeeckstrand, Melkbosstrand and Atlantis, where observation fades with time.

According to Bentley (1996: p. 42) users, rather than designers, form images of layout, the designer merely arranges the physical layout itself to achieve legibility. Legibility can be defined as the quality that makes a place graspable, and that enables people to form clear, accurate images of a city/ structure or new entity. Table Mountain and Robbeneiland are of natural-, historical- and cultural significance. These landmarks contribute to the legibility of Cape Town.

Researchers have explored the contents of these images, using techniques such as interviews, asking directions to places, and getting people to draw maps from memory. Certain types of physical features play a key role in the content of these shared images. Kevin Lynch, an American planner, grouped these features into five key elements, namely nodes, edges, paths, districts and landmarks. These key physical elements are illustrated below.

THE KEY PHYSICAL ELEMENTS, WHICH CONSTITUTE THE SKELETON OF THE URBAN IMAGE – BENTLEY (1996: p. 43)

The character of the respective viewing points is rated in Table 17-29.

17.8. ASSESSMENT OF VISUAL IMPACTS

17.8.1. DESCRIPTION OF METHODOLOGY FOR ASSESSMENT OF SIGNIFICANCE

The Department of Environmental Affairs and Tourism has published a guideline document on the implementation of sections 21, 22 and 26 of the Environment Conservation Act, 1989. The mentioned document states that the significance of impacts can be determined through a synthesis of the aspects produced in terms of the nature, duration, intensity, extent and probability of identified impacts.

Poltech (Pty) Ltd has developed a Significance Assessment Methodology in accordance with the above guidelines. In terms of the above methodology the significance of an impact is the product of a probability rating and a severity rating. This methodology has been adapted by ILA (Pty) Ltd for the purposes of visual impact assessments. A detailed description of the mentioned methodology is as follows.

The Probability Rating is determined from the following, namely:

Improbable - Low possibility of visual impact to occur

- Rating:2

Probable - Distinct possibility that visual impact will occur.

- Rating: 3

Highly probable - Most likely that visual impact will occur.

- Rating: 4

Definite - Visual impact will occur, in the case of adverse impacts regardless of any prevention measures.

- Rating: 5

The Extent factor is awarded to each impact according to the following method:

Low extent - visual perception not affected to a measurable extent or local impact

- Factor 1

Medium extent - regional impact

High extent - national impact

- Factor 4

The duration of the visual impact is assessed and a factor awarded in accordance with the following:

Short term - <1 to 5 years - Factor 2

Medium term - 5 to 15 years - Factor 3

Long term - visual impact will only cease after the operational life of the activity, either because of natural process or by human intervention

- Factor 4.

Permanent - mitigation, either by natural process or by human intervention, will not occur in such a way or in such a time span that the visual impact can be considered transient

- Factor 4.

The severity rating is obtained from calculating a severity factor by multiplication of the Extent and Duration Factors. The Severity factor is used to determine the Severity Rating from Table 17-31.

The Severity factor = Extent factor X Duration factor

= 2 x 3

= 6

Table 17‑30: SEVERITY RATINGS

The Severity Rating and Probability Rating determined by the methodology described above are multiplied to calculate the Significance Rating of the specific environmental impact. The Significance Rating is used to determine the level of mitigation (adverse impacts) required or enhancement (beneficial impacts), as per the following classification, namely:

Positive impact and negative impacts of low significance should have no influence on the proposed development project.

Positive impact:

Should weigh towards a decision to continue with the proposed development.

Negative impact:

Should be mitigated to a level where the impact would be of low significance before project can be approved.

High significance (calculated Significance Rating 16 and more)

Positive impact:

Should weigh towards a decision to continue, should be enhanced in final design.

Negative impact:

Should weigh towards a decision to terminate proposal, or mitigation should be performed to reduce significance to at least low significance rating.

17.8.2. ANTICIPATED VISUAL IMPACTS

Utilising the information reflected in Table 17-27 - Table 17-30, a significance assessment of each visual impact was performed according to the methodology described in section 17.8.1. The results of the significance assessment for the existing Koeberg structures, the additional visual impact of the PBMR (northern site) and the additional impact of the PBMR (southern site) are depicted in Table 17-31, Table 17-32and Table 17-33respectively.

From Table 17-32, it is clear that the most significant viewing points towards the existing Koeberg structures would be the N7, the West Coast road and the Koeberg Private Nature Reserve and the deck of the Visitors centre, due to the location there-of and the category of observers, namely tourists.

The visual impact of the northern site for the proposed PBMR, seen in relation to the existing Koeberg structures, would have a lower significance in comparison to the southern site, as indicated by Table 17-32 and Table 17-33. The visual impact of the northern site for the proposed PBMR, see as a stand-alone structure, would have a lower significance in comparison to the southern site, as indicated by   and  . From these tables it is clear that the anticipated visual impact of the proposed PBMR will be less significant than the impact of the existing Koeberg structures, due to the scale of the proposed structures (refer to Appendix H).

17.8.3.ASSESSMENT OF ALTERNATIVE SITES FOR MODULAR REACTOR IN TERMS OF ASSOCIATED ACTIVITIES

The anticipated visual impacts for the two alternatives, as described in paragraph 17.6.1.,based on a subjective visual evaluation of the study area in terms of the associated activities, are indicated in Table 17-36.

For the purposes of this assessment, the following assumptions were made:

Ü        that the existing intake water stilling basin will not be extended, and

Ü        that the existing residential facilities will not be extended with more that 20 houses for the purposes of the Proposed Pebble Bed Modular Reactor.

that the proposed structure would be viewed from the 3 viewing points with the highest significance rating according to Table 17-32, Table 17-33,   and  , namely the West Coast Road, the National N7 Road and the Koeberg Nature Reserve and deck of the Visitors Centre.

Table 17‑31: SIGNIFICANCE ASSESSMENT OF IDENTIFIED VISUAL IMPACTS OF THE EXISTING KOEBERG STRUCTURES